Fundamentals of Space Medicine (Space Technology Library (23)) [2 ed.] 1441999043, 9781441999047

Table of contents :
Fundamentals of Space Medicine
Copyright
Foreword
Preface
Table of Contents
Chapter 1: Introduction to Space Life Sciences
Chapter 2: Space Biology
Chapter 3: The Neuro-Sensory System in Space
Chapter 4: The Cardio-Vascular System in Space
Chapter 5: The Musculo-Skeletal System in Space
Chapter 6: Psychological Issues of Spaceflight
Chapter 7: Operational Space Medicine
Chapter 8: Life Support Systems
Chapter 9: An Investigator’s Guide
Index

Citation preview

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0UBLISHEDJOINTLYBY-ICROCOSM0RESSAND3PRINGER The Space Technology Library Editorial Board Managing Editor:

James R. Wertz, Microcosm, Inc., El Segundo, CA

Editorial Board:

Val A. Chobotov, Consultant on Space Hazards to the Aerospace Corporation; Michael L. DeLorenzo, Permanent Professor and Head of the Dept. of Astronautics, U.S. Air Force Academy; Roland Doré, Professor and Director International Space University, Strasbourg; Robert B. Giffen, Professor Emeritus, U.S. Air Force Academy; Gwynne Gurevich, Space Exploration Technologies; Wiley J. Larson, Professor, U.S. Air Force Academy; Tom Logsdon, Senior Member of Technical Staff, Space Division, Rockwell International; F. Landis Markley, NASA, Goddard Space Flight Center; Robert G. Melton, Associate Professor of Aerospace Engineering, Pennsylvania State University; Keiken Ninomiya, Professor, Institute of Space & Astronautical Science; Jehangir J. Pocha, Letchworth, Herts.; Frank J. Redd, Professor and Chair, Mechanical and Aerospace Engineering Dept., Utah State University; Rex W. Ridenoure, Jet Microcosm, Inc., Torrance; Malcolm D. Shuster, Professor of Aerospace Engineering, Mechanics and Engineering Science, University of Florida; Gael Squibb, Jet Propulsion Laboratory, California Institute of Technology; Martin Sweeting, Professor of Satellite Engineering, University of Surrey

For further volumes: http://www.springer.com/series/6575

&UNDAMENTALSOF 3PACE-EDICINE Second Edition by

Gilles Clément International Space University, Strasbourg, France

Gilles Clément International Space University Strasbourg France [email protected]

ISBN 978-1-4419-9904-7 e-ISBN 978-1-4419-9905-4 DOI 10.1007/978-1-4419-9905-4 Springer New York Dordrecht Heidelberg London Library of Congress Control Number: 2011929990 © Springer Science+Business Media, LLC 2005, 2011 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

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VII

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PRESSURE ASWELLASSOMENON PATHOLOGICCHANGESTHATBECOMEMALADAPTIVEONRETURN TO%ARTHEG BONELOSS 3PACEPHYSIOLOGYTRIESTOCHARACTERIZEBODILYRESPONSESTO SPACE ESPECIALLYMICROGRAVITY)TPROVIDESTHENECESSARYKNOWLEDGE HENCETHEȃFUN DAMENTALS ȄREQUIREDFORANEFʄCIENTSPACEMEDICINE 3PACEPHYSIOLOGYANDMEDICINEISASOLDASTHEʄRSTʅIGHTOFHUMANSINAHOTAIR BALLOON WHENTHESYMPTOMSOFHYPOXIAWEREʄRSTDISCOVEREDATTHEEXPENSEOFONE PILOTȀSLIFE 4HEINTERESTINTHISʄELDOFRESEARCHKEPTGROWINGALONGWITHTHESPACE PROGRAMANDTHEOPPORTUNITIESITPROVIDEDFORMOREANDMOREHUMANSTOʅYINSPACE ON BOARD CAPSULES SHUTTLES SPACE STATIONS AND SOON SUBORBITAL SPACEPLANES 4HE FUTUREOFHUMANSPACEʅIGHTWILLINEVITABLYLEADTOHUMANMISSIONSTO-ARS4HESE MISSIONSWILLBEOFLONGDURATIONMONTHS INISOLATEDANDSOMEWHATCONʄNED HABITATS WITHTHECREWEXPERIENCINGSEVERALTRANSITIONSINLEVELSOFGRAVITYǻG ǻG ǻG ANDǻG DANGEROUSRADIATION ANDTHECHALLENGESOFLANDINGAND LIVINGONTHEIROWNONANOTHERPLANET )N 4HE &UNDAMENTALS OF 3PACE -EDICINE 3ECOND %DITION SPECIAL EMPHASIS HAS BEENPLACEDONTHECHALLENGES TASKS ANDRESEARCHQUESTIONSTHATMUSTBEADDRESSED BEFORESAFELYSENDINGHUMANSTOEXPLORE-ARS4HEGREATESTTESTFORSPACEMEDICINE WILLBETHEPROJECTEDNEARLY YEARROUND TRIPTO-ARS WHEREASOURCURRENTKNOWLEDGE ONHUMANSINSPACEDOESNOWNOTEXCEEDMONTHSANDFORONLYONEINDIVIDUAL AND THECUMULATIVETIMEINSPACEBYALLASTRONAUTSANDCOSMONAUTSASOFTODAYISCOMPA RABLETOTHELIFETIMEOFONESINGLEINDIVIDUAL4HE!CHILLESȀHEELOFTHE-ARSMISSION MAYBESOMEADVERSEREACTIONSOFTHEHUMANBODY SUCHASBONELOSS DECREASEDMOTOR ANDSENSORYCAPABILITIES ORSIMPLYPSYCHOLOGICALISSUES!CHAINISASSTRONGASITS WEAKESTLINK0OSSIBLEWAYSTOPREVENTPROBLEMSANDCOUNTERMEASURESAREDISCUSSED THROUGHOUTTHEBOOK 4HISBOOKREʅECTSWHATWEDOKNOWINSPACELIFESCIENCESATTHEBEGINNINGOFTHE TWENTY ʄRSTCENTURY)TALSOPOINTSTOTHEMISSINGDATA IE WHATWEDONȀTKNOWAND WHAT WE SHOULD KNOW BEFORE COMMITTING TO INCREASED ACCESS FOR HUMANS IN SPACE INCLUDINGSPACECOMMERCIALPARTICIPANTS BYCONTRASTWITHTHEPROFESSIONALASTRONAUTS ANDFORLONGERDURATIONEXPLORATORYMISSIONS 4HEFORMATOFTHEBOOKISINTENDEDTOFACILITATEITSUSEBYPROFESSORS UNDERGRADUATE ORGRADUATESTUDENTS SPACELIFESCIENTISTS ANDSPACEENTHUSIASTS)TREVIEWSSTEPBY STEPTHECHANGESINTHEMAJORBODYFUNCTIONSDURINGSPACEʅIGHT FROMTHECELLULARLEVEL TOTHEBEHAVIORALANDCOGNITIVELEVELS4OBETTERAPPRECIATETHESECHANGES EACHCHAP TER STARTS WITH A BRIEF REVIEW OF THE BASIC PRINCIPLES OF THESE HUMAN PHYSIOLOGICAL FUNCTIONSON%ARTH s Chapter 1 begins with an introduction to the environmental challenges that spaceflight poses to the human body, and continues with a short history of space life sciences research. s Chapter 2 reviews the effects of microgravity and radiation at the cellular level on bacteria, animals, plants, and humans, including the issues of reproduction and development. s The following chapters each review the effects of spaceflight on the major human body functions: Chapter 3: Neuro-sensory function (the brain in space); Chapter 4: Cardio-vascular function (the heart in space); Chapter 5: Musculo-skeletal function

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IX

(the muscle and bone in space); Chapter 6: Psychological issues (the mind in space). s However, every system or process must ultimately be viewed in the context of the entire body. The consequences of the aforementioned changes at a function level on the health and well being of the astronauts are therefore described in the Chapter 7: Operational Space Medicine. s Chapter 8 focuses on the technical aspects related to life support systems, including radiation shielding, and the challenges for a closed, environmental system for exploration missions. s Chapter 9 concludes this review with some tips from the author on how to proceed with proposing and planning a space experiment that uses humans as test subjects, given the available resources and constraints of current space missions. %ACHCHAPTERCORRESPONDSTOONECORELECTUREOFTHE3PACE,IFE3CIENCES$EPARTMENT OF THE )NTERNATIONAL 3PACE 5NIVERSITY 3PACE 3TUDIES 0ROGRAM 4HESE LECTURES WERE DEVELOPEDWITHTHEHELPOFMANYPEOPLEFROMALLOVERTHEWORLDINACOLLEGIALANDCOL LABORATIVE ENVIRONMENT )N PARTICULAR THE SECTIONS RELATED TO THE MEDICAL EFFECTS OF SPACEʅIGHTAREACONTRIBUTIONOFMYOLDFRIENDANDȃPARTNERINCRIMEȄAT)35 $OUG ȃ(AMIȄ(AMILTON3OMEOFTHEUPDATESTHATAREINCLUDEDINTHISREVISIONHAVEBEEN TAKENNEARLYVERBATIMFROMBOOKSTHAT)HAVEPUBLISHEDSINCETHEʄRSTEDITIONOFTHIS BOOKCAMEOUT !SANEUROPHYSIOLOGISTACTIVELYPARTICIPATINGINSPACERESEARCHSINCE WITH EXPERIMENTSMANIFESTEDON3ALYUT -IR THESPACESHUTTLE ANDTHE)NTERNATIONAL3PACE 3TATION ) KNOW WHAT IT TAKES TO COLLECT DATA DURING RELATIVELY SIMPLE SPACE EXPERI MENTS ANDTHENTRYTOMAKESENSEOFTHESPARSE OFTENCONTRADICTORY RESULTSINASCIEN TIʄCPAPER4HISBOOKPROVIDESASUMMARYOFTHEMAINRESULTS OBSERVATIONS ANDTRENDS DESCRIBEDINTHELITERATURE)APOLOGIZETOTHEAUTHORSOFTHESCIENTIʄCPUBLICATIONSIFALL OFTHEIRINTERPRETATIONSARENOTINCLUDED4HEDETAILEDDESCRIPTIONSOFTHISRESEARCHAND THEʄNDINGSCANBEFOUNDINTHESTUDIESLISTEDINTHEBIBLIOGRAPHY!LISTOFOTHERBOOKS ONSPACELIFESCIENCESISALSOPROVIDED 3OMESPACE RELATEDPHYSIOLOGICALCHANGESANDTHEIRUNDERLYINGMECHANISMSAND INTERPRETATIONS ARE SOMETIMES DESCRIBED IN THE TEXT IN GREATER DETAIL THAN WHAT IS REQUIREDFORAPLENARYACADEMICLECTURE&ORTHECOURSES)TEACHAT)35)HAVEPREPARED 0OWER0OINTPRESENTATIONSCORRESPONDINGTOEACHOFTHECHAPTERSINTHISBOOK4HESE PRESENTATIONSINCLUDEKEYCONCEPTSINBULLET FORMILLUSTRATEDBYRECENTRELEVANTPHOTO GRAPHSANDVIDEOCLIPS0$&VERSIONSOFTHESEPRESENTATIONSASWELLASTHEVIDEOCLIPS AREINCLUDEDONTHEWEBSITE3PRINGER%XTRAS 4HEʄRSTEDITIONOFTHISBOOKHASBEENTRANSLATEDINTO#HINESESEEFRONTCOVERIN &IGURE   3HOULD THERE BE SUFʄCIENT DEMAND NO DOUBT THE PUBLISHER OF THIS BOOK WOULDBEINTERESTEDINPRODUCINGOTHERTRANSLATEDVERSIONS &INALLY THANKSTO!NGIE"UKLEYFOREDITINGTHISBOOKANDBEINGTHEREFORME

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Figure 1 The Front Cover of the Chinese Version of Fundamentals of Space Medicine (First Edition).

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#L¦MENT' 2ESCHKE-& .EUROSCIENCEIN3PACE.EW9ORK .93PRINGER #OLIN * ED  -¦DECINE !¦ROSPATIALE 0ARIS &RANCE %XPANSION 3CIENTIʄQUE &RAN¤AISE $E(ART2,ED  &UNDAMENTALSOF!EROSPACE-EDICINE0HILADELPHIA 0!,EA &EBIGER $E(ART 2, $AVIS *2 EDS  &UNDAMENTALS OF !EROSPACE -EDICINE 4HIRD %DITION0HILADELPHIA 0!,IPPINCOTT7ILLIAMS7ILKINS *OHNSTON23 $IETLEIN,&EDS  "IOMEDICAL2ESULTSFROM3KYLAB7ASHINGTON $# .ATIONAL !ERONAUTICS  3PACE !DMINISTRATION 3CIENTIʄC  4ECHNICAL )NFORMATION/FʄCE .!3!30  +ANAS . -ANZEY $  3PACE 0SYCHOLOGY  0SYCHIATRY .EW 9ORK .9 3PRINGER ,INK--ED  3PACE-EDICINEIN0ROJECT-ERCURY7ASHINGTON $#.ATIONAL !ERONAUTICS3PACE!DMINISTRATION 3CIENTIʄC4ECHNICAL)NFORMATION/FʄCE .!3!30  ,UJAN "& 7HITE 2*  (UMAN 0HYSIOLOGY IN 3PACE 4EACHERȀS -ANUAL ! #URRICULUM3UPPLEMENTFOR3ECONDARY3CHOOLS(OUSTON 485NIVERSITIES3PACE 2ESEARCH!SSOCIATION -OORE$ "IE0 /SER(EDS  "IOLOGICAL-EDICAL2ESEARCHIN3PACE"ERLIN 'ERMANY3PRINGER .ICOGOSSIAN !% ED  4HE !POLLO 3OYUZ 4EST 0ROJECT -EDICAL 2EPORT 7ASHINGTON $# .ATIONAL !ERONAUTICS  3PACE !DMINISTRATION 3CIENTIʄC  4ECHNICAL)NFORMATION/FʄCE .!3!30  .ICOGOSSIAN!% 0ARKER*& 3PACE0HYSIOLOGY-EDICINE7ASHINGTON $# .ATIONAL!ERONAUTICS3PACE!DMINISTRATION 3CIENTIʄC4ECHNICAL)NFORMATION "RANCH .!3!30  .ICOGOSSIAN!% (UNTOON#, 0OOL3,EDS  3PACE0HYSIOLOGY-EDICINE 4HIRD%DITION0HILADELPHIA 0!,EA&EBIGER /SER ( "ATTRICK " EDS  ,IFE 3CIENCES 2ESEARCH IN 3PACE .OORDWIJK 4HE .ETHERLANDS%UROPEAN3PACE!GENCY0UBLICATION$IVISION %3!30  0ARKER*& *ONES7,EDS  "IOMEDICAL2ESULTSFROM!POLLO7ASHINGTON $# .ATIONAL!ERONAUTICS3PACE!DMINISTRATION 3CIENTIʄC4ECHNICAL)NFORMATION /FʄCE .!3!30  0LANEL( 3PACE,IFE!N)NTRODUCTIONTO3PACE"IOLOGY-EDICINE"OCA 2ATON &,#2#0RESS 3TINE(' ,IVINGIN3PACE.EW9ORK .9-%VANS#O

4ABLEOF#ONTENTS

Foreword ..............................................................................................................

v

Preface..................................................................................................................

vii

1

2

Introduction to Space Life Sciences ..............................................................

1

1.1. Space life sciences: what is it? ............................................................. 1.1.1. Objectives ................................................................................ 1.1.2. The space environment............................................................ 1.1.3. Justification for human spaceflight.......................................... 1.1.4. Where we are........................................................................... 1.2. How we got there ................................................................................. 1.2.1. Major space life sciences events ............................................. 1.2.2. Surviving the Odyssey ............................................................ 1.2.3. Life support systems ............................................................... 1.3. Challenges facing humans in space ...................................................... 1.3.1. Astronauts’ health maintenance .............................................. 1.3.2. Environmental health during space missions .......................... 1.3.3. Human Mars mission .............................................................. 1.3.4. Countermeasures ..................................................................... 1.3.5. Artificial gravity ...................................................................... 1.3.6. A new science is born.............................................................. References ......................................................................................................

1 1 4 7 10 12 12 24 27 28 28 31 32 35 37 40 43

Space Biology ................................................................................................

45

2.1. What is life?.......................................................................................... 2.1.1. Life on Earth ........................................................................... 2.1.2. Life on Mars ............................................................................ 2.2. Gravitational biology ............................................................................ 2.2.1. Questions ................................................................................. 2.2.2. Results of space experiments .................................................. 2.2.3. Bioprocessing in space ............................................................ 2.3. Development biology ........................................................................... 2.3.1. Questions ................................................................................. 2.3.2. Results of space experiments ..................................................

45 45 50 51 51 55 61 63 63 66

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XIV

3

2.4.

Plant biology ........................................................................................ 2.4.1. Questions ................................................................................. 2.4.2. Results of space experiments .................................................. 2.5. Radiation biology ................................................................................. 2.5.1. Ionized radiation in space........................................................ 2.5.2. Biological effects of radiation ................................................. 2.6. Facilities for space biology................................................................... 2.6.1. Laboratories on board the ISS ................................................. 2.6.2. Bioprocessing .......................................................................... 2.6.3. Storage and operations ............................................................ References ......................................................................................................

75 75 76 82 82 84 86 86 88 88 90

The Neuro-Sensory System in Space .............................................................

95

3.1. 3.2.

The problem: space motion sickness .................................................... Vestibular function ............................................................................... 3.2.1. The vestibular system .............................................................. 3.2.2. The other senses ...................................................................... 3.3. Posture and movement ......................................................................... 3.3.1. Rest posture ............................................................................. 3.3.2. Vestibulo-spinal reflexes.......................................................... 3.3.3. Locomotion ............................................................................. 3.3.4. Body movement ...................................................................... 3.3.5. Eye movement ......................................................................... 3.4. Spatial orientation ................................................................................ 3.4.1. Visual orientation .................................................................... 3.4.2. Cognition ................................................................................. 3.5. What do we know? ............................................................................... 3.5.1. Space motion sickness experience .......................................... 3.5.2. Theories for space motion sickness......................................... 3.5.3. Countermeasures ..................................................................... References ...................................................................................................... 4

95 99 99 104 113 113 114 115 118 119 124 124 126 132 132 133 135 139

The Cardio-Vascular System in Space ........................................................... 143 4.1. 4.2. 4.3.

4.4.

The problem: postflight orthostatic intolerance.................................... Cardio-vascular system physiology...................................................... 4.2.1. Basics ...................................................................................... 4.2.2. Control mechanisms ................................................................ Effects of spaceflight ............................................................................ 4.3.1. Launch position ....................................................................... 4.3.2. Early on-orbit .......................................................................... 4.3.3. Later on-orbit .......................................................................... 4.3.4. Postflight ................................................................................. What do we know? ............................................................................... 4.4.1. Orthostatic intolerance ............................................................ 4.4.2. Pulmonary function ................................................................. 4.4.3. Bed rest....................................................................................

143 147 147 149 153 153 155 158 164 166 166 168 169

4ABLEOF#ONTENTS

5

6

XV

4.5.

Countermeasures .................................................................................. 4.5.1. In-flight.................................................................................... 4.5.2. End of mission......................................................................... References ......................................................................................................

171 171 175 178

The Musculo-Skeletal System in Space .........................................................

181

5.1.

The problem: muscle atrophy and bone loss ........................................ 5.1.1. Muscle atrophy ........................................................................ 5.1.2. Bone loss ................................................................................. 5.2. Muscle and bone physiology ................................................................ 5.2.1. Muscle physiology .................................................................. 5.2.2. Bone physiology...................................................................... 5.3. Effects of spaceflight on muscle ........................................................... 5.3.1. Decrease in body mass ............................................................ 5.3.2. Decrease in muscle volume and strength ................................ 5.3.3. Changes in muscle structure.................................................... 5.4. Effects of spaceflight on bone .............................................................. 5.4.1. Human studies ......................................................................... 5.4.2. Animal studies......................................................................... 5.5. What do we know? ............................................................................... 5.5.1. Muscle atrophy ........................................................................ 5.5.2. Bone demineralization ............................................................ 5.6. Countermeasures .................................................................................. 5.6.1. Muscle ..................................................................................... 5.6.2. Bone ........................................................................................ 5.6.3. Aging and Space ..................................................................... References ......................................................................................................

181 181 182 184 184 188 191 191 191 193 195 196 198 200 200 201 203 204 208 212 213

Psychological Issues of Spaceflight ...............................................................

217

6.1.

217 221 224 226 227 228 228 229 231 234 234 240 244 246 246 247 253

The problem: reaction to stress ............................................................ 6.1.1. Analogs ................................................................................... 6.1.2. Space simulators...................................................................... 6.1.3. Space missions ........................................................................ 6.1.4. Rules........................................................................................ 6.2. Individual selection .............................................................................. 6.2.1. Select-out criteria .................................................................... 6.2.2. Select-in criteria ...................................................................... 6.2.3. Psychological profiles of astronauts and cosmonauts ............. 6.3. Crew selection ...................................................................................... 6.3.1. Sociological issues .................................................................. 6.3.2. Selection issues ....................................................................... 6.4. Crew behavior and performance .......................................................... 6.5. Psychological training and support ...................................................... 6.5.1. Training ................................................................................... 6.5.2. Support .................................................................................... References ......................................................................................................

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XVI 7

8

Operational Space Medicine ..........................................................................

257

7.1.

Space medicine: what is it? .................................................................. 7.1.1. Objectives ................................................................................ 7.1.2. Risk assessment....................................................................... 7.2. Astronaut selection and training ........................................................... 7.2.1. Crew position .......................................................................... 7.2.2. Physical requirements for astronaut selection ......................... 7.2.3. Selection process ..................................................................... 7.2.4. Astronaut training.................................................................... 7.3. Prevention: health hazards in space ...................................................... 7.3.1. Medical events during spaceflight ........................................... 7.3.2. Sleep ........................................................................................ 7.3.3. Immune system ....................................................................... 7.3.4. Medical aspects of extra-vehicular activity ............................. 7.3.5. Conclusion on space health hazards........................................ 7.4. Treatment: space medical facilities ...................................................... 7.4.1. Crew health care system.......................................................... 7.4.2. Telemedicine ........................................................................... 7.4.3. Emergency and rescue ............................................................. 7.5. Challenges for exploration missions .................................................... References ......................................................................................................

257 259 259 261 261 263 266 268 273 274 277 279 281 285 285 287 294 295 301 302

Life Support Systems .....................................................................................

305

8.1.

305 305 306 307 308 311 311 312 313 318 318 330 330 331 333 333 335 338

Human needs for space missions.......................................................... 8.1.1. Environment ............................................................................ 8.1.2. So, how long will we live? ...................................................... 8.1.3. Human needs ........................................................................... 8.2. Contamination ...................................................................................... 8.3. Major life support system functions ..................................................... 8.3.1. Atmosphere management ........................................................ 8.3.2. Water management .................................................................. 8.3.3. Food management ................................................................... 8.3.4. Hygiene ................................................................................... 8.3.5. Radiation shielding.................................................................. 8.4. Methods for life support systems ......................................................... 8.4.1. Open loop and closed loop ...................................................... 8.4.2. Physical-chemical or biological (bioregenerative) .................. 8.5. Closed ecological life support system .................................................. 8.5.1. CELSS for exploratory missions ............................................. 8.5.2. Terraforming ........................................................................... References ......................................................................................................

4ABLEOF#ONTENTS

XVII

9

An Investigator’s Guide .................................................................................

341

9.1.

341 341 347 353 353 355 356 357 359 360 362 367 368 369

Resources and constraints .................................................................... 9.1.1. Opportunities for space life sciences experiments .................. 9.1.2. Constraints............................................................................... 9.2. How to “fly” an experiment .................................................................. 9.2.1. Flight experiment selection ..................................................... 9.2.2. Experiment design................................................................... 9.2.3. Hardware selection .................................................................. 9.2.4. Feasibility ................................................................................ 9.2.5. Experiment integration ............................................................ 9.2.6. Crew science training .............................................................. 9.2.7. In-flight science operations ..................................................... 9.2.8. Data analysis ........................................................................... 9.3. Benefits to life on Earth ........................................................................ References ......................................................................................................

Index .................................................................................................................... 371

#HAPTER )NTRODUCTIONTO3PACE,IFE3CIENCES

4HISʄRSTCHAPTERDESCRIBESTHEHAZARDSTHATTHESPACEENVIRONMENTPOSESTOHUMANS ANDHOWSPACEʅIGHTAFFECTSTHEHUMANBODYWHEREWEARE 7EWILLTHENREVIEWTHE HISTORICALCONTEXTOFHUMANSPACEʅIGHTHOWWEGOTTHERE ANDENDWITHTHECHAL LENGESFACINGHUMANSINSPACEWHEREDOWEGOFROMHERE &IGURE 

 3PACELIFESCIENCESWHATISIT  /BJECTIVES ,IFESCIENCESARESPECIʄCALLYDEVOTEDTOTHEWORKINGSOFTHELIVINGWORLD FROMBACTE RIAANDPLANTSTOHUMANS INCLUDINGTHEIRORIGINS HISTORY CHARACTERISTICS HABITS YOU NAMEIT 4HESTUDYOFLIFEON%ARTHRANGESFROMELUCIDATINGTHEEVOLUTIONOFTHEEARLIESTSELF REPLICATING NUCLEIC ACIDS TO DESCRIBING A GLOBAL ECOLOGY COMPRISING OVER  MILLION SPECIES INCLUDING HUMANS (OWEVER THROUGHOUT ITS EVOLUTION ORGANISMS ON %ARTH HAVEEXPERIENCEDONLYA GENVIRONMENT4HEINʅUENCEOFTHISOMNIPRESENTFORCEIS NOTWELLUNDERSTOOD EXCEPTTHATTHEREISCLEARLYABIOLOGICALRESPONSETOGRAVITYINTHE STRUCTUREANDFUNCTIONINGOFLIVINGTHINGS4HEPLANTWORLDHASEVOLVEDGRAVITYSEN SORSROOTSGROWȃDOWNȄANDSHOOTSGROWȃUPȄ!NIMALSHAVEGRAVITYSENSORSINTHE INNEREAR-ANYFERTILIZEDEGGSANDDEVELOPINGEMBRYOSAMPHIBIANS ʄSH BIRDS AND MAMMALS ALSOHAVECLEARRESPONSESTOGRAVITY&OREXAMPLE THEAMPHIBIANEGGORI ENTSITSELFWITHRESPECTTOGRAVITYWITHINAFEWMINUTESAFTERFERTILIZATION$URINGTHAT SHORTTIMETHEDORSO VENTRALANDANTERIOR POSTERIORAXESOFTHEFUTUREEMBRYOAREESTAB LISHED$OWECONCLUDETHEREFORETHATTHEGRAVITATIONALINPUTISAREQUIREDSTIMULUSFOR THEESTABLISHMENTOFTHESEAXES 4OBETTERUNDERSTANDASYSTEM THESCIENTIʄCMETHODCONSISTSOFSTUDYINGTHECON SEQUENCES OF ITS EXCLUSION 4HIS APPROACH HAS LED TO CONSIDERABLE ADVANCES IN THE KNOWLEDGEOFHUMANPHYSIOLOGY THANKSTOTHENINETEENTHCENTURYPHYSIOLOGIST#LAUDE "ERNARD WHOSETOUTTHEPRINCIPLESOFEXPERIMENTALMEDICINE#LEARLY THEREMOVALOF GRAVITY IS A DESIRABLE EVEN NECESSARY STEP TOWARD UNDERSTANDING ITS ROLE IN LIVING ORGANISMS )N A SENSE REMOVAL OF GRAVITY FOR STUDYING THE GRAVITY SENSING MECHA NISMS IS LIKE SWITCHING OFF THE LIGHT FOR STUDYING ITS ROLE IN VISION 4RANSITION INTO WEIGHTLESSNESS ABOLISHES THE STIMULUS OF GRAVITY BY A PROCEDURE PHYSIOLOGICALLY EQUIVALENT TO SHUTTING OFF THE LIGHT 7HAT CAN BE ACCOMPLISHED IN SUCH AN ELEGANT FASHIONALOFTCANNEVERBEDONEIN%ARTH BASEDLABORATORIES

G. Clément, Fundamentals of Space Medicine, Space Technology Library 23, DOI 10.1007/978-1-4419-9905-4_1, © Springer Science+Business Media, LLC 2011





&UNDAMENTALSOF3PACE-EDICINE

Figure 1.1. The Goal of Space Medicine Is to Develop Methods to Keep Humans Healthy in Space for Extended Periods of Time, as Well as Improve Overall Health of People of All Ages on Earth. (Credit Philippe Tauzin).

3PACE PHYSIOLOGY IS OF BASIC SCIENTIʄC INTEREST AND DEALS WITH FUNDAMENTAL Q UESTIONSCONCERNINGTHEROLEOFGRAVITYINLIFEPROCESSES3PACEMEDICINEISANOTHER ALBEITMOREAPPLIED RESEARCHCOMPONENTCONCERNEDWITHTHEHEALTHANDWELFAREOFTHE ASTRONAUTS AND SPACE TRAVELERS 4HESE TWO OBJECTIVES COMPLEMENT ONE ANOTHER AND CONSTITUTETHEʄELDOFSPACELIFESCIENCES)NSHORT SPACELIFESCIENCESOPENADOORTO UNDERSTANDINGOURSELVES OUREVOLUTION ANDTHEWORKINGSOFOURWORLDWITHOUTTHE CONSTRAININGBARRIEROFGRAVITY 3PACELIFESCIENCESAREDEDICATEDTOTHEFOLLOWINGTHREEOBJECTIVES %NHANCEFUNDAMENTALKNOWLEDGEINCELLBIOLOGYANDHUMANPHYSIOLOGYǻ!CCESS TOASPACELABORATORYWHEREGRAVITYISNOTSENSEDFACILITATESRESEARCHONTHECELLULARAND MOLECULARMECHANISMSINVOLVEDINSENSINGFORCESASLOWASȪGANDSUBSEQUENTLY TRANSDUCINGTHISSIGNALTOANEURALORHORMONALSIGNAL!MAJORCHALLENGETOOURUNDER STANDINGANDMASTERYOFTHESEBIOLOGICALRESPONSESISTOSTUDYSELECTEDSPECIESOFHIGHER PLANTSANDANIMALSTHROUGHSEVERALGENERATIONSINABSENCEOFGRAVITY(OWDOINDI VIDUALCELLSPERCEIVEGRAVITY7HATISTHETHRESHOLDOFPERCEPTION(OWISTHERESPONSE TOGRAVITYMEDIATED$OESGRAVITYPLAYADETERMINANTROLEINTHEEARLYDEVELOPMENTAND LONG TERMEVOLUTIONOFTHELIVINGORGANISM4HESESTUDIESOFTHEEARLYDEVELOPMENT AND SUBSEQUENT LIFE CYCLES OF REPRESENTATIVE SAMPLES OF PLANTS AND ANIMALS IN THE ABSENCEOFGRAVITYAREOFBASICIMPORTANCETOTHEʄELDOFDEVELOPMENTALBIOLOGY 0ROTECTTHEHEALTHOFASTRONAUTSǻ!SWASAMPLYDEMONSTRATEDBY0ASTEUR ASWELLAS COUNTLESS SUCCESSORS INVESTIGATIONS IN MEDICINE AND AGRICULTURE CONTRIBUTE TO AND BENEʄTFROMBASICRESEARCH5NDERSTANDINGTHEEFFECTOFGRAVITYONHUMANSANDPLANTS HASENORMOUSPRACTICALSIGNIʄCANCEFORHUMANSPACEʅIGHT&OREXAMPLE THEPROCESS OFBONEDEMINERALIZATIONSEENINHUMANSANDANIMALSASAPROGRESSIVEPHENOMENON

)NTRODUCTIONTO3PACE,IFE3CIENCES



OCCURRINGDURINGSPACEʅIGHTISNOTONLYASERIOUSMEDICALPROBLEM)TALSORAISESTHE QUESTIONOFABNORMALITIESINTHEDEVELOPMENTOFBONES SHELLS ANDTHEOTOLITHSOFTHE INNEREARINSPECIESDEVELOPINGINTHEABSENCEOFGRAVITY4HESTUDYOFSUCHABNORMALI TIESSHOULDPROVIDEINSIGHTINTOTHEPROCESSOFBIOMINERALIZATIONANDTHECONTROLOF GENETRANSCRIPTION $EVELOP ADVANCED TECHNOLOGY AND APPLICATIONS FOR SPACE AND GROUND BASED RESEARCHǻ)NADDITIONTOTHESCIENTIʄCNEEDTOSTUDYBASICPLANTANDANIMALINTERAC TIONSWITHGRAVITY THEREISAPRACTICALNEEDTOSTUDYTHEIRRESPONSES4HESEAREESSENTIAL TOOURULTIMATEABILITYTOSUSTAINHUMANSFORAYEARORMOREONTHESURFACEOFEXTRATER RESTRIALBODIESORINSPACEʅIGHTMISSIONSOFLONGDURATIONWHERERE SUPPLYISNOTPOS SIBLE AND FOOD MUST BE PRODUCED IN SITU %XPERIMENTS DURING LONG DURATION SPACE MISSIONSWILLDETERMINEWHICHPLANTSANDANIMALSAREMOSTEFʄCIENTANDBESTSUITED FOROURNEEDS&ORINSTANCE CANSOYBEANSGERMINATE GROWNORMALLY PRODUCEOPTI MUMCROPSOFNEWSOYBEANSFORFOODANDNEWSEEDFORENSURINGFUTURECROPS!LLOF THISBIOLOGICALCYCLING PLUSTHEDEVELOPMENTOFEQUIPMENTFORWATERANDATMOSPHERIC RECYCLING PLUSMANAGEMENTOFWASTE WILLALSOBRINGIMPORTANTBENEʄTSFORTERRESTRIAL APPLICATIONS !LSO THE ABSENCE OF GRAVITY IS USED TO ELIMINATE MICRO CONVECTION IN CRYSTALGROWTH INELECTROPHORESIS ANDINBIOCHEMICALREACTIONS4HERESULTINGPROD UCTSCANBEUSEDFORBOTHRESEARCHANDCOMMERCIALAPPLICATION 3PACELIFESCIENCESINCLUDETHESCIENCESOFPHYSIOLOGY MEDICINE ANDBIOLOGY AND ARELINKEDWITHTHESCIENCESOFPHYSICS CHEMISTRY GEOLOGY ENGINEERING ANDASTRON OMY3PACELIFESCIENCESRESEARCHNOTONLYHELPUSTOGAINNEWKNOWLEDGEOFOUROWN HUMANFUNCTIONANDOURCAPACITYTOLIVEANDWORKINSPACEBUTALSOTOEXPLOREFUNDA MENTALQUESTIONSABOUTGRAVITYȀSROLEINTHEFORMATION EVOLUTION MAINTENANCE AND AGINGPROCESSESOFLIFEON%ARTH4ABLE  Table 1.1.

Major Applications of Space Life Sciences Research.

Biology s !DVANCEUNDERSTANDINGOFCELLBEHAVIOR s )MPROVECROPYIELDSUSINGLESSNUTRIENTSANDSMALLERSURFACEANDVOLUME Biotechnology s 0ROVIDEINFORMATIONTODESIGNANEWCLASSOFDRUGSTOTARGETSPECIlCPROTEINSANDCURE SPECIlCDISEASES s #ULTURETISSUEFORUSEINCANCERRESEARCH SURGERY BONECARTILAGE ANDNERVEINJURIES Medicine s %NHANCEMEDICALUNDERSTANDINGOFDISEASEPROCESSESSUCHASOSTEOPOROSIS s !DVANCEFUNDAMENTALUNDERSTANDINGOFTHENERVOUSSYSTEMANDDEVELOPNEWMETHODS TOPREVENTANDTREATVARIOUSNEUROLOGICALDISORDERS s $EVELOPMETHODSTOKEEPHUMANSHEALTHYINLOW GRAVITYENVIRONMENTSFOREXTENDEDTIME PERIODS Education s 5SESCIENCEONORBITTOENCOURAGEANDSTRENGTHENSCIENCEEDUCATIONON%ARTH

&UNDAMENTALSOF3PACE-EDICINE

 

4HESPACEENVIRONMENT

4HESPACEENVIRONMENTRADIATION MICROGRAVITY VACUUM MAGNETICʄELDS ASWELLAS THE LOCAL PLANETARY ENVIRONMENTS -OON -ARS HAVE BEEN EXTENSIVELY REVIEWED IN 0ETER%CKARTȀSBOOK3PACEʅIGHT,IFE3UPPORTAND"IOSPHERICS )NTHISSECTION WEWILLMAINLYFOCUSONMICROGRAVITY4HEMEDICALISSUESRELATEDTOSPACERADIATION WILLBEDEVELOPEDIN#HAPTER  -ICROGRAVITY 4HEPRESENCEOF%ARTHCREATESAGRAVITATIONALʄELDTHATACTSTOATTRACTOBJECTSWITHA FORCEINVERSELYPROPORTIONALTOTHESQUAREOFTHEDISTANCEBETWEENTHECENTEROFTHE OBJECTANDTHECENTEROF%ARTH7HENWEMEASURETHEACCELERATIONOFANOBJECTACTED UPONONLYBY%ARTHȀSGRAVITYAT%ARTHȀSSURFACE WECOMMONLYREFERTOITASGORONE %ARTHȀSGRAVITY4HISACCELERATIONISAPPROXIMATELYMS 7ECANINTERPRETTHETERMMICROGRAVITYINANUMBEROFWAYS DEPENDINGUPONTHE CONTEXT;2OGERSETAL=4HEPREʄXMICRO DERIVESFROMTHEORIGINAL'REEKMIKROS MEANINGȃSMALLȄ"YTHISDEʄNITION AMICROGRAVITYENVIRONMENTISONETHATIMPARTSTO ANOBJECTANETACCELERATIONTHATISSMALLCOMPAREDWITHTHATPRODUCEDBY%ARTHATITS SURFACE7ECANACHIEVESUCHANENVIRONMENTBYUSINGVARIOUSMETHODS INCLUDING %ARTH BASEDDROPTOWERS PARABOLICAIRCRAFTʅIGHTS AND%ARTH ORBITINGLABORATORIES)N PRACTICE SUCHACCELERATIONSWILLRANGEFROMABOUTOF%ARTHȀSGRAVITATIONALACCEL ERATIONONBOARDANAIRCRAFTINPARABOLICʅIGHT TOBETTERTHANONEPARTINAMILLIONON BOARD A SPACE STATION  %ARTH BASED DROP TOWERS CREATE MICROGRAVITY ENVIRONMENTS WITHINTERMEDIATEVALUESOFRESIDUALACCELERATION 1UANTITATIVESYSTEMSOFMEASUREMENT SUCHASTHEMETRICSYSTEM COMMONLYUSE MICRO TO MEAN ONE PART IN A MILLION "Y THIS SECOND DEʄNITION THE ACCELERATION IMPARTED TO AN OBJECT IN MICROGRAVITY WILL BE Ȫ OF THAT MEASURED AT %ARTHȀS SURFACE 4HEUSEOFTHETERMMICROGRAVITYINTHISBOOKCORRESPONDSTOTHEʄRSTDEʄNITION SMALLGRAVITYLEVELSORLOWGRAVITY -ICROGRAVITYCANBECREATEDINTWOWAYS"ECAUSEGRAVITATIONALPULLDIMINISHES WITHDISTANCE ONEWAYTOCREATEAMICROGRAVITYENVIRONMENTISTOTRAVELAWAYFROM %ARTH4OREACHAPOINTWHERE%ARTHȀSGRAVITATIONALPULLISREDUCEDTOONE MILLIONTHOF THATATTHESURFACE WEWOULDHAVETOTRAVELINTOSPACEADISTANCEOFMILLIONKILO METERSFROM%ARTHALMOSTTIMESFARTHERAWAYTHANTHE-OON 4HISAPPROACHIS IMPRACTICAL EXCEPTFORAUTOMATEDSPACECRAFT (OWEVER THEACTOFFREEFALLCANCREATEAMOREPRACTICALMICROGRAVITYENVIRONMENT !LTHOUGHAIRCRAFT DROPTOWERFACILITIES ANDSMALLROCKETSCANESTABLISHAMICROGRAVITY ENVIRONMENT ALLOFTHESELABORATORIESSHAREACOMMONPROBLEM!FTERAFEWSECONDS ORMINUTESOFLOW G %ARTHGETSINTHEWAYANDTHEFREE FALLSTOPS4OESTABLISHMICRO GRAVITYCONDITIONSFORLONGPERIODSOFTIME ONEMUSTUSESPACECRAFTINORBIT4HEYARE LAUNCHEDINTOATRAJECTORYTHATARCSABOVE%ARTHATTHERIGHTSPEEDTOKEEPTHEMFALLING WHILEMAINTAININGACONSTANTALTITUDEABOVETHESURFACE .EWTON;=ENVISIONEDACANNONATTHETOPOFAVERYTALLMOUNTAINEXTENDING ABOVE%ARTHȀSATMOSPHERESOTHATFRICTIONWITHTHEAIRWOULDNOTBEAFACTOR ʄRINGCAN NONBALLS PARALLEL TO THE GROUND .EWTON DEMONSTRATED HOW ADDITIONAL CANNONBALLS WOULDTRAVELFARTHERFROMTHEMOUNTAINEACHTIMEIFTHECANNONʄREDUSINGMOREBLACK

)NTRODUCTIONTO3PACE,IFE3CIENCES



Figure 1.2. Artificial Satellites Are Made to Orbit Earth When Their Velocity Is Equal or Higher Than 7.8 km/s. 7HENIN/RBIT THE3PACECRAFTAND)TS)NHABITANTS!REINA 3TATEOF#ONTINUOUS&REE &ALLWITH.O!PPARENT0ERCEPTIONOF'RAVITY#REDIT0HILIPPE Tauzin).

POWDER7ITHEACHSHOT THEPATHWOULDLENGTHEN ANDSOONTHECANNONBALLSWOULD DISAPPEAROVERTHEHORIZON%VENTUALLY IFONEʄREDACANNONWITHENOUGHENERGY THE CANNONBALL WOULD FALL ENTIRELY AROUND %ARTH AND COME BACK TO ITS STARTING POINT 4HECANNONBALLWOULDBEGINTOORBIT%ARTH0ROVIDEDNOFORCEOTHERTHANGRAVITYINTER FERED WITH THE CANNONBALL MOTION IT WOULD CONTINUE CIRCLING %ARTH IN THAT ORBIT &IGURE  4HISISHOWTHESPACESHUTTLESTAYSINORBIT)TLAUNCHESINTOATRAJECTORYTHATARCS ABOVE%ARTHSOTHATTHEORBITERTRAVELSATTHERIGHTSPEEDTOKEEPITFALLINGWHILEMAIN TAININGACONSTANTALTITUDEABOVETHESURFACE&OREXAMPLE IFTHESPACESHUTTLECLIMBS TOA KMHIGHORBIT ITMUSTTRAVELATASPEEDOFABOUT KMHTOACHIEVEA STABLEORBIT!TTHATSPEEDANDALTITUDE DUETOTHEEXTREMELYLOWFRICTIONOFTHEUPPER ATMOSPHERE THESPACESHUTTLEEXECUTESAFALLINGPATHPARALLELTOTHECURVATUREOF%ARTH )N OTHER WORDS THE SPACECRAFT GENERATES A CENTRIFUGAL ACCELERATION THAT COUNTERBAL ANCES%ARTHȀSGRAVITATIONALACCELERATIONATTHATVEHICLEȀSCENTEROFMASS4HESPACE CRAFT IS THEREFORE IN A STATE OF FREE FALL AROUND %ARTH AND ITS OCCUPANTS ARE IN A MICROGRAVITYENVIRONMENT'RAVITYPERSEISONLYREDUCEDBYABOUTATTHEALTITUDE OFLOW%ARTHORBIT,%/ BUTTHEMORERELEVANTFACTISTHATGRAVITATIONALACCELERATION ISESSENTIALLYCANCELEDOUTBYTHECENTRIFUGALACCELERATIONOFTHESPACECRAFT  /THERFACTORSOFTHESPACEENVIRONMENT "ESIDEMICROGRAVITY DURINGSPACEʅIGHTLIVINGORGANISMSAREALSOAFFECTEDBYIONIZING RADIATION ISOLATION CONʄNEMENT AND CHANGES IN CIRCADIAN RHYTHMS THE  H DAY NIGHT CYCLE  )N PLANTS FOR EXAMPLE SPACEʅIGHT OFFERS THE UNIQUE OPPORTUNITY TO SEPARATETHEGRAVITATIONALINPUTFROMOTHERENVIRONMENTALSTIMULIKNOWNTOINʅUENCE



&UNDAMENTALSOF3PACE-EDICINE

Figure 1.3. Gravitropism Is the Way Plants Grow in Response to the Pull of Gravity. When 0LACED .EAR A 7INDOW 0LANTS %XHIBIT 0HOTOTROPISM "ENDING 4OWARD THE ,IGHT 3OURCE  4HIS "EHAVIOR #AN "E %ASILY /BSERVED BY 0LACING A 0LANT ON )TS 3IDE 7ITHIN-INUTESTHE2OOTSAND3TEM"EGINTO2EORIENT4HEMSELVESIN2ESPONSETO "OTH'RAVITYAND,IGHT#REDIT.!3! 

PLANTGROWTH FOREXAMPLE PHOTOTROPISM&IGURE WATERTROPISM ANDTHECIRCADIAN INʅUENCESOFTHETERRESTRIALENVIRONMENT3PACEʅIGHTTHUSPROVIDESTHEOPPORTUNITYTO DISTINGUISHBETWEENTHEVARIOUSTROPICRESPONSESANDTOINVESTIGATETHEMECHANISMSOF STIMULUSDETECTIONANDRESPONSE 4HEABSENCEOFNATURALLIGHTINSPACECRAFTMAYHAVESIGNIʄCANTEFFECTSONHUMANS TOO!TYPICALPERSONSPENDSHISDAYSOUTDOORS EXPOSEDTOLIGHTPROVIDEDBYTHE3UNȀS RAYSʄLTEREDTHROUGHTHEOZONELAYER INCLUDINGASMALLBUTIMPORTANTAMOUNTOFMID ANDNEAR ULTRAVIOLETLIGHT ANDAPPROXIMATELYEQUALPORTIONSOFTHEVARIOUSCOLORSOF VISIBLELIGHT)NDOORLIGHTINGINMOSTOFʄCESANDINSPACECRAFTISOFAMUCHLOWERINTEN SITY AND IF EMITTED BY ʅUORESCENT ȃDAYLIGHTȄ OR ȃCOOL WHITEȄ BULBS IS DEʄCIENT IN ULTRAVIOLET LIGHT AND THE BLUES AND REDS AND EXCESSIVE IN THE LIGHT COLORS YELLOW GREEN THATAREBESTPERCEIVEDASBRIGHTNESSBYTHERETINA )FTHEONLYEFFECTOFLIGHTONHUMANSWASTOGENERATESUBJECTIVEBRIGHTNESS THENTHIS ARTIʄCIALLIGHTSPECTRUMMIGHTBEADEQUATE)THASBECOMECLEAR HOWEVER THATLIGHT HAS NUMEROUS ADDITIONAL PHYSIOLOGICAL AND BEHAVIORAL EFFECTS &OR EXAMPLE LIGHT EXERTSDIRECTEFFECTSONCHEMICALSNEARTHESURFACEOFTHEBODY PHOTOACTIVATINGVITA MIN$PRECURSORSANDDESTROYINGCIRCULATINGPHOTO ABSORBENTCOMPOUNDSMELANIN  )TALSOEXERTSINDIRECTEFFECTSVIATHEEYEANDBRAINONNEUROENDOCRINEFUNCTIONS CIRCA DIAN RHYTHMS SECRETIONS FROM THE PINEAL ORGAN AND MOST CLEARLY ON MOOD -ANY PEOPLEEXHIBITMAJORSWINGSINMOODSEASONALLY INPARTICULARTOWARDDEPRESSIONIN THEFALLANDWINTER WHENTHEHOURSOFDAYLIGHTARETHESHORTEST7HENPATHOLOGICAL THE SEASONALAFFECTIVEDISORDERSYNDROMEISADISEASERELATEDTOEXCESSIVESECRETIONOFTHE PINEALHORMONE MELATONIN WHICHALSOMAYBETREATABLEWITHSEVERALHOURSPERDAYOF SUPPLEMENTALLIGHT7HILENOTYETPROVED ITSEEMSHIGHLYLIKELYTHATPROLONGEDEXPO SURETOINADEQUATELIGHTINGTHATIS THEWRONGSPECTRUM ORTOOLOWANINTENSITY ORTOO FEWHOURSPERDAYOFLIGHT MAYADVERSELYAFFECTMOODANDPERFORMANCE ,OW POWERLIGHTEMITTINGDIODES,%$ AREFASTBECOMINGAȃGREENȄLIGHTINGALTER NATIVEFORCONVENTIONALLIGHTING,%$AREKNOWNTOUSELESSELECTRICITY TOBEQUIETER LASTLONGER ANDPRODUCEALOWAMOUNTOFHEATCOMPAREDTOCONVENTIONALLIGHTSOURCES 2ECENT STUDIES DEMONSTRATED THAT ,%$ WITH A SPECTRUM OF BLUE ORANGE AND RED

)NTRODUCTIONTO3PACE,IFE3CIENCES



P ROVIDEDTHEEXACTBANDWIDTHFORPLANTSTOGROWANDPRODUCEFOODONTHE)33!SIN OURHOME THECOMPACTʅORESCENTANDOTHERLEGACYLIGHTINGSOURCESWILLBEPROGRES SIVELYREPLACEDWITH,%$ONBOARDTHE)33 4HEEFFECTSOFSPACEʅIGHTONBIOLOGICALSPECIMENSMIGHTALSOBERELATEDTOOTHER FACTORS%VENTHEGENTLESTOFLAUNCHVEHICLESPRODUCESENORMOUSAMOUNTSOFNOISEAND VIBRATION PLUSELEVATEDGFORCES UNTILORBITALVELOCITYISACHIEVED ORDURINGTHERE ENTRY INTO %ARTHȀS ATMOSPHERE /NCE IN ORBIT MACHINES AND ASTRONAUTS CONTINUE TO PRODUCEVIBRATIONSTHATAREDIFʄCULTTOCONTROL4HESPACEENVIRONMENTALSOEXPOSES ANIMALSANDINDIVIDUALSTOHIGH ENERGYRADIATIONUNLIKEANYTHINGTHEYEXPERIENCEON %ARTH4OCONTROLTHESEANDOTHEREXTERNALFACTORSFOREXAMPLE ʅUCTUATIONSINATMO SPHERICPRESSUREASASTRONAUTSENTERANDEXITASPACECRAFT THEBIOLOGISTSSTUDYINGTHE EFFECTSOFMICROGRAVITYPERSEIDEALLYNEEDONBOARDCENTRIFUGESTHATCANEXPOSECON TROLSPECIMENSTOTHELEVELOFGRAVITYFOUNDON%ARTHȀSSURFACE;7ASSERSUG = 

*USTIʄCATIONFORHUMANSPACEʅIGHT

 (UMANSVERSUSROBOTS 4HE DEBATE OVER SPACE EXPLORATION IS OFTEN FRAMED AS HUMANS VERSUS ROBOTS 3OME SCIENTISTSFEARTHATSENDINGHUMANSTOTHE-OONAND-ARSMIGHTPRECLUDETHEPURSUIT OFHIGHQUALITYSCIENCE/NTHEOTHERHAND SOMEPROPONENTSOFHUMANEXPLORATIONARE CONCERNEDTHATDOINGASMUCHSCIENCEASPOSSIBLEUSINGROBOTSWOULDDIMINISHINTEREST INSENDINGHUMANS.EVERTHELESS HUMANSWILLALWAYSBEINCOMMAND4HEQUESTION ISWHEREWOULDTHEYMOSTEFFECTIVELYSTAND 3PACEEXPLORATIONSHOULDBETHOUGHTOFASAPARTNERSHIPTOWHICHROBOTSANDHUMANS EACHCONTRIBUTEIMPORTANTCAPABILITIES/PPOSINGROBOTICSVERSUSHUMANCREWSISLIKE COMPARING APPLES AND ORANGES 4HE DISCUSSION MUST BE FRAMED IN TERMS OF RELATIVE STRENGTHSOFHUMANSANDROBOTSINEXPLORINGTHE-OONAND-ARS&OREXAMPLE ROBOTS ARE PARTICULARLY GOOD AT REPETITIVE TASKS )N GENERAL ROBOTS EXCEL IN GATHERING LARGE AMOUNTSOFDATAANDDOINGSIMPLEANALYSES(ENCE THEYCANBEDESIGNEDFORRECONNAIS SANCE WHICHINVOLVESHIGHLYREPETITIVEACTIONSANDSIMPLEANALYSIS!LTHOUGHTHEYARE DIFʄCULT TO RECONʄGURE FOR NEW TASKS ROBOTS ARE ALSO HIGHLY PREDICTABLE AND CAN BE DIRECTEDTOTESTHYPOTHESESSUGGESTEDBYTHEDATATHEYGATHER(OWEVER ROBOTSARESUB JECTTOMECHANICALFAILURE DESIGNANDMANUFACTURINGERRORS ANDERRORSBYHUMANOPER ATORS!LSO BEFOREROBOTSCANEXPLOREANDʄNDEVIDENCEOFLIFEON-ARS FORINSTANCE THEIRFUNCTIONALCAPABILITIES PARTICULARLYTHEIRMOBILITY NEEDTOBERADICALLYIMPROVED ANDENHANCED)NADDITION THEDELAYINCOMMUNICATIONBETWEEN-ARSAND%ARTHINTHE ORDEROFMINROUNDTRIP POSESASERIOUSPROBLEMFORTELEOPERATIONMANEUVERS 0EOPLE ONTHEOTHERHAND ARECAPABLEOFINTEGRATINGANDANALYZINGDIVERSESENSORY INPUTSANDOFSEEINGCONNECTIONSGENERALLYBEYONDTHEABILITYOFROBOTS(UMANSCAN RESPONDTONEWSITUATIONSANDADAPTTHEIRSTRATEGIESACCORDINGLY)NADDITION THEYARE INTELLIGENTOPERATORSANDEFʄCIENTEND EFFECTORS4HEYMAYEASILYDOBETTERTHANAUTO MATEDSYSTEMSINANYNUMBEROFSITUATIONS EITHERBYDERIVINGACREATIVESOLUTIONFROM AGOODʄRSTHANDLOOKATAPROBLEMORBYDELIVERINGAMOREBRAINLESSKICKINTHERIGHT PLACETOFREEASTUCKANTENNA%ITHERMAYBEMISSIONSAVING&INALLY ONLYHUMANSARE ADEPTATʄELDSCIENCE WHICHDEMANDSALLOFTHESEPROPERTIES/BVIOUSLY HUMANSWOULD HAVEACLEARROLEINDOINGGEOLOGICALʄELDWORKANDINSEARCHINGFORLIFEON-ARS



&UNDAMENTALSOF3PACE-EDICINE

Figure 1.4. Robonaut 2 Is a Dexterous Humanoid Robot Developed Jointly by NASA and General Motors.4HESE 3OCIAL 2OBOTS !RE $ESIGNED TO 5SE THE 3AME4OOLS AS (UMANS !LLOWING 4HEM TO 7ORK 3AFELY 3IDE BY 3IDE (UMANS ON %ARTH AND IN 3PACE#REDIT.!3! 

(UMANSAREALSOLESSPREDICTABLETHANROBOTSANDSUBJECTTOILLNESS HOMESICKNESS STRESSRESULTINGFROMCONʄNEMENT HUNGER THIRST ANDOTHERHUMANCHARACTERISTICS4HEY NEEDPROTECTIVESPACESUITSANDPRESSURIZEDHABITATS(ENCE THEYREQUIREFARGREATERAND MORECOMPLICATEDANDEXPENSIVESUPPORTTHANROBOTS4HECOMBINEDPOTENTIALOFHUMANS ANDROBOTSISAPERFECTEXAMPLEOFTHESUMEQUALINGMORETHANTHEPARTS)TWILLALLOWUS TOGOFARTHERANDACHIEVEMORETHANWECANPROBABLYEVENIMAGINETODAY!FUTUREGEN ERATIONOFROBOTS THESO CALLEDSOCIALROBOTS HASPROMISEBOTHINSPACEANDON%ARTH NOT ASREPLACEMENTSFORHUMANSBUTASCOMPANIONSTHATCANCARRYOUTKEYSUPPORTINGROLES $EXTEROUSROBOTSWITHHUMAN LIKEHANDSANDARMS ABLETOUSETHESAMETOOLSASASTRO NAUTS ARECURRENTLYUNDERGOINGEXTENSIVETESTINGONBOARDTHE)33&IGURE )NTHE FUTURETHESESOCIALROBOTSMAYASSISTORSTANDINFORASTRONAUTSDURINGSPACEWALKSAND PLANETARYEXPLORATIONORFORTASKSTOODIFʄCULTORDANGEROUSFORHUMANS  3PACESCIENCE 4HERE IS OFTEN CRITICISM THAT HUMAN MISSIONS ARE DISPROPORTIONATELY COSTLY TO THEIR SCIENTIʄCYIELDASCOMPAREDTOAUTOMATICUNMANNED PLATFORMSSUCHASTHOSEDESIGNED FOR3OLAR3YSTEMEXPLORATIONOR%ARTHȀSOBSERVATION!DIRECTCOMPARISONISNOTJUSTI ʄED HOWEVER !UTOMATIC PROBES HAVE INDEED RETURNED SPECTACULAR RESULTS BUT IT IS WRONGTOCOMPARETHESEDIRECTLYWITHHUMANʅIGHTS(ISTORICALLY SPACELIFESCIENCES AREARATHERRECENTDISCIPLINE)NMOSTSPACEAGENCIES ATLEASTUNTILRECENTLY THETERM ȃSPACESCIENCEȄREFERSTOSPACEPHYSICALSCIENCES SUCHASASTROPHYSICSORSEARCHFOR LIFEONOTHERPLANETS0ERHAPSREMINISCENTOFTHISPAST HUMANSPACEʅIGHTCRITICSOFTEN DISCOUNT THE VALUE OF SPACE LIFE SCIENCES ON THE ȃ$ISCOVERY ,EDGER "IG "OOK Ȅ

 )NA&EBRUARYINTERVIEWTOTHE#HICAGO4RIBUNE APHYSICSPROFESSORATTHE5NIVERSITYOF-ARYLAND AND A DIRECTOR AT THE !MERICAN 0HYSICAL 3OCIETY A PROFESSIONAL ORGANIZATION OF PHYSICISTS SAID ȃ4HE )NTERNATIONAL3PACE3TATIONISNOTEXPLORATIONITȀSGOINGINCIRCLESCLOSERTOTHE%ARTHTHAN"ALTIMOREISTO .EW9ORKȄ(EADDEDȃ)TISTHESINGLEGREATESTOBSTACLEOFCONTINUEDEXPLORATIONOFTHE3OLAR3YSTEMǼITȀS BLOCKINGJUSTABOUTEVERYTHINGȄ

)NTRODUCTIONTO3PACE,IFE3CIENCES



4HIS POINT OF VIEW IS OFTEN DUE TO THE FOLLOWING FUNDAMENTAL DIFFERENCES PHYSICAL SCIENCESLEADSTOMORECONCRETEDISCOVERIESINARELATIVELYUNEXPLOREDSPHEREONCEA NEWSTARISDISCOVERED ITISEASYTOCONʄRMITSPRESENCE WHEREASSPACELIFESCIENCES ISANINHERENTLYINEXACTSCIENCE WHICHMUSTTAKEINTOACCOUNTBACKGROUNDPHYSIOLOGI CALVARIABILITYANDREQUIRESREPEATEDMEASUREMENTS&ORINSTANCE LARGECLINICALTRIALS ARENEEDEDTODETERMINETHEEFʄCACYOFANEWDRUG)TMAYBEOBVIOUSTHATSPACELIFE SCIENCESSUFFERFROMTHESMALLNUMBEROFSUBJECTSSTUDIEDANDTHEMANYCONFOUNDING FACTORSTHATAREDIFʄCULTTOCONTROL"UTWITHALLOFTHIS ITISLIKELYTHATTHELIFESCIENCES DATAOBTAINEDIN,%/STUDIESWILLBEPRACTICALLYUSEDFORGOINGFURTHERSUCHASESTAB LISHINGA-ARSBASE ORFORIMPROVINGOURKNOWLEDGEOFCLINICALANDAGINGDISORDERS ON%ARTH LONGBEFOREWECANMAKEUSEOFTHEINFORMATIONONTHEMAGNETICʄELDOF .EPTUNE;"ARRATT = )T IS TRUE THAT THE COST OF HUMAN BASED SPACE INFRASTRUCTURES SUCH AS THE )33 IS MUCHHIGHERTHANUNMANNEDMISSIONS(OWEVER THEPRIMARYPURPOSEFORTHE)33WAS APOLITICALONE4HE)33ISAMAJORACCOMPLISHMENTFORALLCOUNTRIESINVOLVEDEVENIN ITSCURRENTINCOMPLETESTATE)TISTHELARGESTON ORBITSTRUCTUREEVERBUILTANDTHELARGEST MULTI NATIONALCOOPERATIVEPROJECTINHISTORY)NBUILDINGTHE)33INFRASTRUCTUREAND RESEARCHEQUIPMENT AEROSPACECOMPANIESAREACQUIRINGUNIQUECAPABILITIESTHATMAKE THEMRECOGNIZEDWORLDPLAYERSINAREASSUCHASSPACESTRUCTURES AUTOMATION ROBOTICS AVIONICS ʅUIDHANDLING ADVANCEDLIFESUPPORTSYSTEMSANDMEDICALEQUIPMENT"OTH INVIEWOFTHENEEDTODEVELOPADVANCEDTECHNOLOGIESANDBYVIRTUEOFTHERESEARCH CARRIEDOUTONBOARD THE)33CANHAVEASIGNIʄCANTIMPACTONTHECOMPETITIVENESSOF AEROSPACEINDUSTRY)NTHESAMEWAYTHATONEWOULDNOTCHARGETHECOSTOFAROAD SYSTEM TO A SINGLE CAR OR EVEN THE ʄRST DOZEN CARS THE COST OF THE )33 CANNOT BE ENDORSEDBYTHESCIENTIʄCRETURNOFITSʄRSTEXPERIMENTS 4HE OPPORTUNITIES FOR IN DEPTH STUDIES IN SPACE LIFE SCIENCES HAVE INDEED BEEN SPARSE4HISISSIMPLYTHENATUREOFTHECURRENTSPACEPROGRAM WITHMUCHTODOANDA FEWʅIGHTOPPORTUNITIESTHATMUSTBESHARED%XPERIMENTSTHATMIGHTTAKEWEEKSON %ARTHTAKEYEARSTOPLANANDEXECUTEINSPACE,IMITATIONSOFTHESPACEʅIGHTENVIRON MENTHAVEALSOLIMITEDTHENUMBEROFCONTROLEXPERIMENTSANDHAVEOFTENKEPTTHE NUMBEROFSPECIMENSSTUDIEDFARFROMSTATISTICALIDEAL/FTENSPACESTUDIESAREPARAL LELEDBY%ARTH BASEDSIMULATIONSTUDIESUSINGCENTRIFUGESORCLINOSTATS BUTRESULTSIN ACTUALMICROGRAVITYARESOMEWHATDIFFERENT !NOTHERARGUMENTOFTENPOSEDAGAINSTSPACELIFESCIENCESISTHATNO.OBELPRIZES HAVEBEENGIVENINTHISʄELDOFRESEARCH!LTHOUGHATRUESTATEMENT THEREARESEVERAL INSTANCES HOWEVER OF.OBEL0RIZESFORMERLYDELIVEREDINLIFESCIENCESRELATEDʄELDS THATWOULDPRESUMABLYNOTHAVEBEENPRESENTEDBASEDONTHERECENTRESULTSOBTAINEDIN SPACE&OREXAMPLE 2OBERT"RNY A6IENNESEOTOLARYNGOLOGIST RECEIVEDTHE.OBEL 0RIZEOF-EDICINEINFORHISDISCOVERYOFACLINICALTESTAIMEDATEVALUATINGTHE FUNCTIONALITY OF THE BALANCE ORGANS IN THE INNER EAR SEE #HAPTER  3ECTION   $URINGTHISTEST IRRIGATIONOFTHEEXTERNALAUDITORYEARWITHWATERORAIRABOVEORBELOW BODY TEMPERATURE GENERATES RHYTHMIC EYE MOVEMENTS NYSTAGMUS AND THE SUBJECT EXPERIENCESSLIGHTVERTIGO"RNYȀSTHEORYWASTHATTHECALORICIRRIGATIONOFTHEEAR CANALGENERATEDEYEMOVEMENTSTHESO CALLEDCALORICNYSTAGMUS BECAUSEOFTHEHEAT GRAVITY DRIVENCONVECTIONWITHINTHECANALʅUID;"ARANY =!SPACEEXPERIMENT CARRIEDOUTONBOARD3PACELABINPROVEDTHISTHEORYTOBEWRONGSINCECALORIC NYSTAGMUS WAS ALSO OBSERVED IN MICROGRAVITY WHERE NO HEAT CURRENT CONVECTION IS



&UNDAMENTALSOF3PACE-EDICINE

GENERATED,ATERSTUDIESREVEALEDTHATITISMORELIKELYTHECHANGESINPRESSUREOR TEMPERATURETHATAREATTHEORIGINOFTHEEYEMOVEMENTRESPONSE;3CHERERETAL =  7HEREWEARE (UMANSPACEʅIGHTBEGANIN!PRILWITH9URI'AGARINȀSSINGLEORBITOFTHE%ARTHON BOARD6OSTOK %XACTLYYEARSLATER IN!PRIL ATOTALOFASTRONAUTS COSMO NAUTS ANDTA«KONAUTSTHENAMEGIVENTO#HINESEASTRONAUTS WILLHAVEʅOWNINSPACE  ANAVERAGEOFABOUTPERYEAR4HETOTALNUMBEROFDAYSSPENTINSPACEWILLBEABOUT  CREWDAYS ORYEARS)TISINTERESTING ORRATHERSAD TONOTETHATFEMALEASTRO NAUTS AND COSMONAUTS COMPRISE ONLY  OF THESE  ʅOWN INDIVIDUALS  TO BE EXACT &EMALESALSOCONTRIBUTEDTOABOUTOFALLHUMANʅIGHTS ANDTHETOTAL DURATIONOFALLʅIGHTSFORFEMALEASTRONAUTSANDCOSMONAUTSISLESSTHANYEARS !LLTOGETHER THESEHUMANSWILLHAVESPENTABOUT DAYSINSPACE3O THE AVERAGE AMOUNT OF TIME SPENT IN SPACE BY ASTRONAUTS AND COSMONAUTS IS  DAYSDAYS ORALITTLEMORETHANMONTHS)FWEINCLUDETHERE ʅIGHTS THENUMBEROFʅOWNHUMANSGOESUPTO FORTHESHUTTLEONLY NEARLY
 (OWEVER MOSTOFTHEMHAVESPENTLESSTHANDAYSINSPACE EVENBYCUMULATING THREE OR FOUR ʅIGHTS 4HE MEAN DURATION OF ALL HUMAN SPACEʅIGHTS TO DATE IS ABOUT DAYS BUTTHEMEDIANTIMESPENTINORBITISCLOSETODAYS&IGURE &LIGHT DURATIONLONGERTHANMONTHSISLIMITEDTOABOUTINDIVIDUALS ANDONLYFOURINDI VIDUALSHAVEEXPERIENCEDCONTINUOUSSPACEʅIGHTLONGERTHANYEAR&IGURE "Y COUNTING THE RE ʅIGHTS  INDIVIDUALS INCLUDING ONE FEMALE HAVE CUMULATED THE EQUIVALENTOFYEARORMOREINORBIT

Figure 1.5. Number of Human Spaceflights as a Function of Flight Duration from 1961 to 2010..OTETHE,OGARITHMIC3CALEFOR&LIGHT$URATION-OST(UMAN&LIGHTS7EREOF 3HORT$URATIONnDAYS ON"OARD3OYUZORTHE3PACE3HUTTLE

 0ROVIDEDTHAT343  3OYUZ4-!  AND343 LAUNCHONTIMETHESECALCULATIONSWEREMADEON /CTOBER 

)NTRODUCTIONTO3PACE,IFE3CIENCES



Figure 1.6. Cumulative Histogram Showing the Astronaut and Cosmonaut Count as a Function of (Single) Flight Duration.

(AD ALL THE ASTRONAUTS AND COSMONAUTS BEEN THE SUBJECTS OF SPACE LIFE SCIENCES INVESTIGATIONS DURING THEIR SPACEʅIGHT THE TOTAL AMOUNT OF COLLECTED DATA WOULD BE LIMITEDTOABOUTONEHUMANLIFETIME4HETOTALAMOUNTOFCOLLECTEDDATAONFEMALE SUBJECTSWOULDBELIMITEDTOYEARSǻTHECONCEPTOFWOMENʅYINGINSPACEISSTILLAT ITSINFANCY9ET SINCELIFESCIENCESINVESTIGATIONSWERENOTCONDUCTEDONALLASTRONAUTS ANDCOSMONAUTS ANDSINCEMOSTOFTHEMHAVEʅOWNMORETHANONCE THELIMITEDNUM BEROFINDIVIDUALSANDOBSERVATIONSMAKESTHESIGNIʄCANCEOFTHISDATAEVENLOWER 4HISSIMPLEARITHMETICISTOILLUSTRATEHOWLITTLERESEARCHTIMEǻONHOWFEWSPACE ʅYERS ǻ IS CURRENTLY AVAILABLE TO DETERMINE THE EFFECTS OF SPACEʅIGHT ON THE HUMAN BODY!COMPARISONBETWEENSPACERESEARCHANDEXTREMEENVIRONMENTRESEARCHWOULD UNDOUBTEDLYSHOWTHATMUCHMOREHASBEENACCOMPLISHEDON-OUNT%VERESTORDUR INGPOLAREXPEDITIONSDURINGTHESAMEPERIOD 4HE RECORD OF SPACEʅIGHT DURATION IS CURRENTLY HELD BY $R 6ALERY 0OLYAKOV A 2USSIANPHYSICIAN WHOSPENTDAYSDURINGASINGLEMISSIONONBOARDTHESPACE STATION-IRINǻ4HISWASHISSECONDSPACEʅIGHT THOUGH)N HEHAD ALREADY SPENT  DAYS ON BOARD -IR SO HIS TOTAL TIME SPENT IN SPACE ACTUALLY IS DAYS ORABOUTMONTHS "UTTHISISNOTTHELONGESTDURATIONINSPACEFORASINGLEINDIVIDUAL3ERGEY+RIKALYOV HASLOGGEDDAYSDURINGSIXSTAYSONBOARD-IR THESPACESHUTTLE ANDTHE)33 AND HECURRENTLYHOLDSTHEALL TIMECUMULATIVETOTALFORDAYSINSPACE"ESIDE0OLYAKOV AND +RIKALYOV EIGHT OTHER COSMONAUTS HAVE SPENT MORE THAN  DAYS IN SPACE !BOUT INDIVIDUALSHAVESUCCESSFULLYCLIMBEDTOTHETOPOF-OUNT%VERESTSINCE-AY!SOF ABOUT ASCENTSHAVEBEENMADE/VERPEOPLEHAVEDIEDTRYING!BOUTINDIVIDUALSHAVE COMPLETED EXPEDITIONS TO THE .ORTH 0OLE OR THE 3OUTH 0OLE SINCE  AND  RESPECTIVELY ;3OURCE WWWADVENTURESTATSCOM=





&UNDAMENTALSOF3PACE-EDICINE

A CCUMULATEDOVERTWOTOʄVESPACEʅIGHTS4HISCUMULATIVETIMEINMICROGRAVITYIS ABOUTEQUALTOTHETOTALEXPOSURETOMICROGRAVITYTOBEEXPERIENCEDDURINGAMISSION TO-ARS4HE)33ALLOWSEXTENSIVEINVESTIGATIONSONHUMANSINSPACE(OWEVER THE NOMINAL DURATION OF A STAY IN ORBIT FOR %XPEDITION CREWS ON )33 DOES NOT EXCEED  MONTHS 4HEREFORE NO DATA IS GAINED ANYMORE DURING VERY LONG SPACEʅIGHTS !LTHOUGHWEKNOWTHATHUMANSCANSURVIVETOLONGDURATIONINSPACEREPEATEDLY THE DATACOLLECTEDSOFARISEXTREMELYLIMITED 4HERE IS A GENERAL PERCEPTION THAT BECAUSE A SMALL NUMBER OF COSMONAUTS HAVE SURVIVEDIN,%/FORASLONGASYEARORSO THEREARENOMAJORPHYSIOLOGICALPROBLEMS LIKELYTOPRECLUDELONGER DURATIONHUMANPLANETARYEXPLORATIONMISSIONS/NEMUST ADMIT THAT OVER THE YEARS THERE HAS BEEN ACCESS ONLY TO ANECDOTAL DATA FROM THE 2USSIAN SPACE PROGRAM 4HIS ANECDOTAL INFORMATION IS WHILE INTERESTING NOT SUFʄ CIENTLYRELIABLEFORDRAWINGCONCLUSIONSFORANUMBEROFREASONS4HEREAREDIFFERENCES INTHESCIENTIʄCMETHOD THEEXPERIMENTALPROTOCOLS ANDTHEEQUIPMENT4HERESULTS AREALSONOTPUBLISHEDINPEER REVIEWEDINTERNATIONALSCIENTIʄCJOURNALS&ORTUNATELY THEINCREASEDRECENTCOOPERATIVEACTIVITIESBETWEEN2USSIAANDITSPARTNERSOFTHE)33 NOWALLOWASTANDARDIZATIONOFEXPERIMENTALPROCEDURESANDBETTERDATAEXCHANGE

 (OWWEGOTTHERE  -AJORSPACELIFESCIENCESEVENTS  4HEPIONEERS 4HEʄRSTPOWEREDʅIGHTINBYTHE7RIGHT"ROTHERSAT+ITTY(AWKBEACHIN.ORTH #AROLINAISTRADITIONALLYCONSIDEREDASTHEMILESTONEINMANNEDʅIGHTANDAEROSPACE MEDICINE)NMYTHOLOGY )CARUSWASTHEʄRSTVICTIMOFAʅYINGADVENTURE WHENHEAND HISFATHER$AEDALUSTRIEDTOESCAPETHEIRPRISONONTHEISLANDOF#RETEBYʅYINGUSING WAXEDFEATHERS4HELEGENDSAYSTHAT)CARUS IGNORINGBOTHADVICEANDWARNING ʅEW TOOCLOSETOTHE3UN4HEHEATSOFTENEDTHEWAXANDTHEFEATHERSDETACHED PRECIPITAT INGADREADFULFALLFOR)CARUS (OWEVER THEREWERENOWITNESSESTOTHE)CARUSAND$AEDALUSʅIGHT4HISWASNOT THECASEFORTHESECONDHUMANʅIGHTINHISTORY THOUGH)N*UNE TWOBROTHERS *ACQUES%TIENNEAND*OSEPH-ICHEL-ONTGOLʄER SENTALARGE SMOKED ʄLLEDBAGFT INTOTHEAIR4HISʄRSTBALLOONʅIGHTWASRECORDEDBYTHE&RENCH!CADEMYOF3CIENCES 4HREEMONTHSLATER ADUCK AROOSTER ANDASHEEPBECAMETHEʄRSTPASSENGERSINABAL LOON SINCENOONEKNEWWHETHERAHUMANCOULDSURVIVETHEʅIGHT!LLTHREEANIMALS SURVIVEDTHEʅIGHT ALTHOUGHTHEDUCKWASFOUNDWITHABROKENLEG PRESUMABLYDUETO AKICKFROMTHESHEEPAFTERLANDING&INALLY ON.OVEMBER  HUMANʅIGHTWAS ATTEMPTEDBEFOREAVASTCROWDTHATINCLUDEDTHEKINGANDQUEENOF&RANCEANDRECOG NIZEDSCIENTISTS;4ILLETETAL =0ILATREDE2OZIERSANDTHE-ARQUISDȀ!RLANDES PILOTEDWHATBECAMETHEʄRSTKNOWNAERIALVOYAGEOFHUMANKIND&IGURE 

4HEWORDȃPILOTȄISDERIVEDFROMHISNAME 4HE-ARQUISDȀ!RLANDESWASBORNINMYHOMETOWN !NNEYRON ASMALLVILLAGEINTHESOUTHOF&RANCE

 

)NTRODUCTIONTO3PACE,IFE3CIENCES



Figure 1.7. Drawing of the First Manned Balloon Flight Taking Off in Front of the Château de la Muette with passengers Pilatre de Roziers and the Marquis d’Arlandes. 3OURCE5NKNOWN 

!FTERTHISEVENT BALLOONINGBECAMEQUITEPOPULARFOROVERHALFACENTURYIN%UROPE 4ENDAYSAFTERTHEʄRSTMANNEDHOTAIRʅIGHT A&RENCHPHYSICISTNAMED*!##HARLES MADETHEʄRSTHUMANʅIGHTINAHYDROGEN ʄLLEDBALLOON7HENHEREACHEDANALTITUDE OF M HEBEGANTOEXPERIENCEPHYSIOLOGICALLYSOMEOFTHEREALITIESOFTHISNEW ENVIRONMENT(ECOMPLAINEDOFTHEPENETRATINGCOLDATTHISALTITUDEANDASHARPPRES SUREPAININONEEARASHEDESCENDED4HISISTHEʄRSTDESCRIPTIONOFSYMPTOMSEXPERI ENCEDINAEROSPACEMEDICINE)NIN%NGLAND AFTERSEVERALANIMALSWEREUSEDIN FREE ʅIGHT TESTS -RS %LISABETH 4IBLE BECAME THE ʄRST WOMAN TO ʅY A BALLOON AND *EAN 0IERRE"LANCHARDBECAMETHEʄRSTTOCROSSTHE#HANNELFROM%NGLANDTO&RANCE &EELINGOUTDONE 0ILATREDE2OZIERSBUILTANEWBALLOON USINGACOMBINATIONOFHOTAIR ENVELOPEANDASMALLHYDROGENBALLOON TOʅYFROM&RANCETO%NGLAND)N*ANUARY  HELEFT&RANCE ANDAFTERAFEWMINUTESIN ʅIGHTTHEBURNERȀSʅAMEIGNITEDTHE SMALL HYDROGEN BALLOON CREATING AN INFERNO )RONICALLY THE ʄRST TO ʅY IN A BALLOON BECAME THE ʄRST BALLOON CASUALTY 4HE HAZARDS OF HIGH ALTITUDE ʅIGHT WERE DEMON STRATEDINFOLLOWINGʅIGHTS WHEREBALLOONISTSEXPERIENCEDANDDESCRIBEDFORTHEʄRST TIME THE SYMPTOMS OF HYPOXIA ALTITUDE SICKNESS INCREASE IN HEART RATE FATIGUE ;$E(ART =



&UNDAMENTALSOF3PACE-EDICINE

 !NIMALSPACEʅIGHT )NTHES ASHUMANSPACEʅIGHTBEGANTOBESERIOUSLYCONSIDERED MOSTSCIENTISTS ANDENGINEERSPROJECTEDTHATIFSPACEʅIGHTBECAMEAREALITYITWOULDBUILDUPONLOGICAL BUILDINGBLOCKS&IRST AHUMANWOULDBESENTINTOSPACEASAPASSENGERINACAPSULE 0ROJECTS6OSTOKAND-ERCURY 3ECOND THEPASSENGERSWOULDACQUIRESOMECONTROL OVERTHESPACEVEHICLE0ROJECTS3OYUZAND'EMINI 4HIRD AREUSABLESPACEVEHICLE WOULD BE DEVELOPED THAT WOULD TAKE HUMANS INTO ,%/ AND RETURN THEM .EXT A PERMANENTSPACESTATIONWOULDBECONSTRUCTEDIN,%/THROUGHTHEUTILIZATIONOFTHE REUSABLE SPACE VEHICLE &INALLY LUNAR AND INTERPLANETARY ʅIGHTS WOULD BE LAUNCHED FROMTHESPACESTATIONUSINGRELATIVELYLOW THRUSTANDREUSABLEANDTHUSLOWERCOST SPACEVEHICLES *USTLIKEFORBALLOONʅIGHTS ANIMALSWERESENTUPINROCKETSBEFOREHUMANSTOTEST IFALIVINGBEINGCOULDWITHSTANDANDSURVIVEAJOURNEYINTOSPACE&IGURE 4HE ʄRSTSUCCESSFULSPACEʅIGHTINVOLVINGLIVINGCREATURESCAMEON3EPTEMBER  WHENTHEFORMER3OVIET5NIONLAUNCHEDASOUNDINGROCKETWITHACAPSULEINCLUDINGA MONKEYANDMICE!FEWATTEMPTSTOʅYANIMALSHADBEENMADEBEFOREINFACT SINCE  IN THE NOSE CONES OF CAPTURED 'ERMAN 6  ROCKETS DURING 53 LAUNCH TESTS BUTSOMETHINGALWAYSWENTWRONG4HESEATTEMPTSWEREMADEWITHONEMAIN PURPOSE TO STUDY THE EFFECTS OF EXPOSURE TO SOLAR RADIATION AT HIGH ALTITUDE AND TO DETERMINETHEEFFECTS IFANY OFWEIGHTLESSNESS;,UJANAND7HITE = /RBITALʅIGHTTHENBEGANON/CTOBER  WHENTHEFORMER3OVIET5NIONSENTTHE 3PUTNIK SATELLITEINTOSPACE4HISWASANUNMANNEDSATELLITE BUTBEFORETHEENDOFTHE YEARASECONDSATELLITE 3PUTNIK  WASLAUNCHEDCARRYINGTHEʄRSTLIVINGCREATUREINTO ORBIT A DOG NAMED ,AIKA ,AIKA HAD BEEN EQUIPPED WITH A COMPREHENSIVE ARRAY OF TELEMETRYSENSORS WHICHGAVECONTINUOUSPHYSIOLOGICALINFORMATIONTOTRACKINGSTA TIONS4HECABINCONDITIONINGSYSTEMMAINTAINEDSEA LEVELATMOSPHERICPRESSUREWITHIN

Figure 1.8. Rats and Cats Were the First Living Passengers on a Suborbital Flight in a French Rocket in the 60s.#REDIT#.%3 

)NTRODUCTIONTO3PACE,IFE3CIENCES



THE CABIN AND ,AIKA SURVIVED  DAYS BEFORE DEPLETION OF THE OXYGEN STORES CAUSED ASPHYXIATION ,AIKAȀS ʅIGHT DEMONSTRATED THAT SPACEʅIGHT WAS TOLERABLE TO ANIMALS 4WELVEOTHERDOGS ASWELLASMICE RATS ANDAVARIETYOFPLANTSWERETHENSENTINTO SPACEFORLONGERANDLONGERDURATIONBETWEENAND)N A3OVIETBIOSAT ELLITE#OSMOSMISSIONCARRIEDTWODOGSINORBITFORDAYS4HEDOGSWEREOBSERVED VIAVIDEOTRANSMISSIONANDBIOMEDICALTELEMETRY4HEIRSPACECRAFTLANDEDSAFELY )N ONERHESUSANDONESQUIRRELMONKEYRODEINTHENOSECONEOFA53MIS SILEDURINGANON ORBITALʅIGHT SUCCESSFULLYWITHSTANDINGTIMESTHENORMALPULLOF GRAVITY AND A WEIGHTLESS PERIOD OF ABOUT  MIN 4HEIR SURVIVAL OF SPEEDS OVER  KMHWASTHEʄRSTSTEPTOWARDPUTTINGAHUMANINTOSPACE!LTHOUGHONEOFTHE MONKEYSDIEDFROMTHEEFFECTSOFANESTHESIAGIVENTOALLOWTHEREMOVALOFELECTRODES IMPLANTEDFORTHESPACEʅIGHT ASUBSEQUENTAUTOPSYREVEALEDTHATTHEMONKEYHADSUF FEREDNOADVERSEEFFECTSFROMTHEʅIGHT"ETWEENAND THREEOTHERMONKEYS MADESUBORBITALʅIGHTSIN-ERCURYCAPSULES ANDONEMONKEYʅEWTWOORBITSAROUND %ARTH IN A -ERCURY CAPSULE IN PREPARATION FOR THE NEXT HUMAN ʅIGHT &IGURE   4HESEEXPERIMENTSPAVEDTHEWAYFORHUMANEXPEDITIONS !COMPREHENSIVELISTOFALLTHEANIMALSPECIESTHATHAVEʅOWNINSPACEISPUBLISHED INTHEBOOK&UNDAMENTALSOF3PACE"IOLOGYBY#L¦MENTAND3LENZKA; 3PRINGER= 7HILE THESE ANIMALS WERE IN SPACE INSTRUMENTS MONITORED VARIOUS PHYSIOLOGICAL RESPONSESASTHEANIMALSEXPERIENCEDTHESTRESSESOFLAUNCH RE ENTRY ANDTHEWEIGHT LESSENVIRONMENT4HERESULTSOFTHESEANIMALʅIGHTSSHOWEDTHAT A 0ULSE AND RESPIRATION RATES DURING BOTH THE BALLISTIC AND THE ORBITAL ʅIGHTS REMAINEDWITHINNORMALLIMITSTHROUGHOUTTHEWEIGHTLESSSTATE#ARDIACFUNCTION ASEVALUATEDFROMTHEELECTROCARDIOGRAMSANDPRESSURERECORDS WASALSOUNAF FECTEDBYTHEʅIGHTS

Figure 1.9. Chimpanzee Ham with Biosensors Attached Is Being Prepared for His Trip in the Mercury-Redstone 2 on January 31, 1961.#REDIT.!3! 



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B "LOODPRESSURES INBOTHTHESYSTEMICARTERIALTREEANDTHELOW PRESSURESYSTEM WERENOTSIGNIʄCANTLYCHANGEDFROMPREʅIGHTVALUESDURINGHOFTHEWEIGHTLESS STATE C 0ERFORMANCEOFASERIESOFTASKSOFGRADEDMOTIVATIONANDDIFʄCULTYWASUNAF FECTEDBYTHEWEIGHTLESSSTATE D !NIMALSTRAINEDINTHELABORATORYTOPERFORMDURINGTHESIMULATEDACCELERATION NOISE ANDVIBRATIONOFLAUNCHANDRE ENTRYWEREABLETOMAINTAINPERFORMANCE THROUGHOUTANACTUALʅIGHT /NTHEBASISOFTHESERESULTS ITWASCONCLUDEDTHATTHEPHYSICALANDMENTALDEMANDS THATTHEASTRONAUTSWOULDENCOUNTERDURINGSPACEʅIGHTȃWOULDNOTBEEXCESSIVE ȄAND THEADEQUACYOFTHELIFESUPPORTSYSTEMWASDEMONSTRATED;(ENRY =  (UMANSINSPACE %ARLIER INLATE THENEW.ATIONAL!ERONAUTICS3PACE!DMINISTRATION.!3! HAD ANNOUNCED 0ROJECT -ERCURY ITS ʄRST MAJOR UNDERTAKING 4HE OBJECTIVES WERE THREEFOLDTOPLACEAHUMANSPACECRAFTINTOORBITALʅIGHTAROUND%ARTH OBSERVEHUMAN PERFORMANCEINSUCHCONDITIONS ANDRECOVERTHEHUMANANDTHESPACECRAFTSAFELY!T THISEARLYPOINTINTHE53SPACEPROGRAM MANYQUESTIONSREMAINED#OULDAHUMAN PERFORMNORMALLYASAPILOT ENGINEER EXPERIMENTERINTHEHARSHCONDITIONSOFWEIGHT LESSʅIGHT)FYES WHOWERETHERIGHTPEOPLEWITHTHERIGHTSTUFF FORTHISCHALLENGE )N .!3!RECEIVEDANDSCREENEDSERVICERECORDSOFAGROUPOFTALENTED TESTPILOTS FROMWHICHCANDIDATESWEREASSEMBLED/NEMONTHLATER THROUGHA VARIETYOFINTERVIEWSANDABATTERYOFWRITTENTESTS THE.!3!SELECTIONCOMMITTEE BROUGHTDOWNTHISGROUPTOCANDIDATES%ACHCANDIDATEENDUREDEVENMORESTRIN GENTPHYSICAL PSYCHOLOGICAL ANDMENTALEXAMINATIONS INCLUDINGTOTALBODY8 RAYS PRESSURESUITTESTS COGNITIVEEXERCISES ANDASERIESOFUNNERVINGINTERVIEWS/FTHE CANDIDATES WERERECOMMENDEDFOR0ROJECT-ERCURYWITHOUTMEDICALRESERVATIONS !TAPRESSCONFERENCE .!3!INTRODUCEDTHESEVEN-ERCURYASTRONAUTSTOTHEPUBLIC 4HEFOLLOWINGYEAR THE3OVIET5NIONANNOUNCEDTHATʄGHTERPILOTSHADBEEN SELECTEDFORITSSPACEPROGRAM0HYSIOLOGICALSTUDIESANDSPECIALPSYCHOPHYSIOLOGICAL METHODSȃPERMITTEDTHESELECTIONOFPEOPLEBESTʄTTEDTODISCHARGETHEMISSIONSACCU RATELYANDWHOHADTHEMOSTSTABLENERVESANDEMOTIONALHEALTH ȄACCORDINGTOTHE 3OVIET REPORT )N   FEMALE PARACHUTISTS JOINED THIS ʄRST GROUP OF  MALE COSMONAUTS /N!PRIL  9URI'AGARINBECAMETHEʄRSTHUMANTOORBIT%ARTH!CCORDING TOTHEPRESSRELEASE 'AGARINFELTȃPERFECTLYWELLȄTHROUGHOUTTHEORBITINGPHASEAND ALSODURINGTHEPERIODOFWEIGHTLESSNESS)TWASNOTED HOWEVER THATȃMEASURESȄHAD BEENTAKENTOPROTECTTHESPACECRAFTFROMTHEHAZARDSOFSPACERADIATION 3IXWEEKSLATER 530RESIDENT+ENNEDYWOULDANNOUNCEASANATIONALOBJECTIVEAN ACCELERATEDSPACEPROGRAMTOACCOMPLISHALANDINGONTHE-OONBEFORETHEENDOFTHE DECADE(OWEVER AFTERTHESUBORBITALʅIGHTSOF!LAN3HEPARDAND'US'RISSOMIN-AY AND*ULY RESPECTIVELY OBSERVATIONSMADEDURING53ORBITALSPACEʅIGHTSWITH MONKEYSRAISEDSOMECONCERNS6ARIATIONSINCARDIACRHYTHMHADBEENRECORDEDINONE CHIMPANZEEDURINGATHREE ORBITMISSION;3TRINGLY =)TWASFOUNDTHATTHEPROBLEM CAMEFROMFAULTYINSTRUMENTATION ANDTHATTHEDATAWERETHEREFOREINVALID!CCORDINGLY ITWASRECOMMENDEDTHAT*OHN'LENNȀSORBITALʅIGHTPROCEEDASSCHEDULED

)NTRODUCTIONTO3PACE,IFE3CIENCES



Figure 1.10. Russian Cosmonauts Yuri Gagarin and Valentina Tereshkova Were the First Male and Female Humans into Space.3OURCE5NKNOWN 

)N !UGUST OF THE SAME YEAR AFTER 'RISSOMȀS SUBORBITAL ʅIGHT IN *ULY THE 5332 LAUNCHED#OSMONAUT'HERMAN34ITOVINTOORBIT4HEFOLLOWINGDAY 4ITOVSUCCESS FULLYLANDEDAFTERORBITSINHANDMIN4HISWASTHEʄRSTHUMANʅIGHTOFMORE THANONEORBIT ANDTHEʄRSTTESTOFHUMANRESPONSESTOPROLONGEDWEIGHTLESSNESS4WO YEARS LATER IN  6ALENTINA 4ERESHKOVA BECAME THE ʄRST WOMAN IN SPACE &IGURE 3HEREMAINEDINSPACEFORNEARLYDAYSANDORBITEDTHE%ARTHTIMES 5NLIKEEARLIER3OVIETSPACEʅIGHTS 4ERESHKOVAWASPERMITTEDTOOPERATETHECONTROLS MANUALLY!FTERHERSPACECRAFTREENTERED%ARTHȀSATMOSPHERE 4ERESHKOVAPARACHUTED TOTHEGROUND ASWASTYPICALOFCOSMONAUTSATTHATTIME!LTHOUGHHERSPACEʅIGHTWAS ANNOUNCEDASSUCCESSFUL ITWASYEARSUNTILANOTHERWOMANʅEWINSPACE 3VETLANA 3AVITSKAYA ABOARD3OYUZ4 AND3ALYUT IN!PPARENTLY SOMETHINGWENTSO WRONGDURING4ERESHKOVAȀSʅIGHTTHATNOFURTHERʅIGHTSINCLUDEDWOMEN3AVITSKAYA MUSTHAVETURNEDOUTALLRIGHT SINCESHEʅEWTWICE ANDDURINGHERSECONDMISSIONON BOARD3OYUZ4 AND3ALYUT IN*ULY WASTHEʄRSTWOMANTOEVERPERFORMA SPACEWALK4HETHIRDANDLASTFEMALE2USSIANCOSMONAUTʅEWINONBOARDTHE SPACESHUTTLEAND-IR 3OVIET#OSMONAUT!LEKSEI,EONOVMADETHEʄRSTSPACEWALKDURINGTHE6OSKHOD  MISSIONON-ARCH (EWASFOLLOWEDBY53!STRONAUT%DWARD7HITE WHO STEPPEDOUTOF'EMINI FORMIN7HITEPROPELLEDHIMSELFAWAYFROMTHESPACE CRAFTWITHASPECIALGUNTHATGUSHEDOUTCOMPRESSEDOXYGENTOMOVEHIMINANYDIREC TION(OWEVER BECAUSEHISPROPULSIONGUNRANOUTOFFUEL HEHADTOPULLONHISLIFE SUPPORTSYSTEMUMBILICALLINETOMANEUVERAROUNDANDREENTERTHESPACECRAFT  3PACELIFESCIENCESINVESTIGATIONS 4HE -ERCURY ʅIGHTS HAD MADE IT CLEAR THAT THE BODY UNDERGOES SOME REAL CHANGES DURINGANDAFTERSPACEʅIGHT SUCHASMEASURABLEWEIGHTLOSS!MORECOMPLEXSETOF IN ʅIGHTMEDICALSTUDIESWASCARRIEDOUTDURINGTHE'EMINIMISSIONS WHICHSERVEDAS PRECURSORSTOTHELUNARMISSIONS!MONGTHOSEMISSIONS 'EMINI ȀS$ECEMBER PRIMARY OBJECTIVE WAS TO CONDUCT A  WEEK MISSION AND EVALUATE THE EFFECTS OF



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LONG DURATION EXPOSURE TO WEIGHTLESSNESS ON ITS CREW -ANY MEDICAL EXPERIMENTS WERECONDUCTEDIN ʅIGHT INCLUDINGONVISIONANDSLEEP%XTENSIVETESTING FOREXAM PLEONBALANCE WASALSOPERFORMEDJUSTAFTERLANDING"LOODANDURINESAMPLESWERE COLLECTED THROUGHOUT THE MISSION FOR ANALYSIS AND ASTRONAUTS EXERCISED TWICE DAILY USINGRUBBERBUNGEECORDS /FPARTICULARINTERESTWASTHEVISUALACUITYEXPERIMENT WHICHWASDRIVENBYEARLIER OBSERVATIONSOF-ERCURYASTRONAUTSWHOTHOUGHTTHEIRABILITYTOIDENTIFYSMALLOBJECTS ON %ARTHȀS SURFACE WAS ENHANCED IN WEIGHTLESSNESS 4HIS EXPERIMENT USED A VISUAL ACUITYGOGGLECOMBINEDWITHMEASUREDOPTICALPROPERTIESOFGROUNDOBJECTSANDTHEIR NATURALLIGHTING ASWELLASTHEATMOSPHEREANDSPACECRAFTWINDOW4HERESULTSFAILED TOSHOWTHATVISUALACUITYWASIMPROVEDWHILEINSPACE !LSOINTERESTINGISTHE'EMINI ʅIGHT3EPTEMBER WHEREARTIʄCIALGRAVITY WAS ACCIDENTALLY ʄRST TESTED IN SPACE 4HE 'EMINI SPACECRAFT WAS TETHERED TO AN !GENATARGETVEHICLEBYALONG$ACRONLINE CAUSINGTHETWOVEHICLESTOSPINSLOWLY AROUNDEACHOTHER!CCORDINGTOTHE'EMINICOMMANDER A46CAMERAFELLȃDOWNȄIN THE DIRECTION OF THE CENTRIFUGAL FORCE BUT THE CREW DID NOT PERCEIVE ANY CHANGES ;#L¦MENTAND"UKLEY = 3IGNIʄCANT ORTHOSTATIC HYPOTENSION AND WEIGHT LOSS WERE OBSERVED IN THE CREW MEMBERS OF 'EMINI    AND Ȫ IMMEDIATELY AFTER ʅIGHT SEE #HAPTER  3ECTION !LSO REDBLOODCELLMASSLOSSESINTHEORDEROFWERENOTEDAFTER THE DAY'EMINIʅIGHT3CIENTISTSWERECONCERNEDTHATSPACEʅIGHTMIGHTAFFECTTHE BALANCEOFBODYʅUIDSANDELECTROLYTESBECAUSEʅUIDLOSSESCANCONTRIBUTETOBOTHOF THESESYMPTOMS4HISLEDTOASERIESOFGROUND BASEDSTUDIESTOSIMULATESOMEOFTHE CONDITIONSOFSPACEʅIGHT4HESESTUDIESUTILIZEDBEDRESTANDWATERIMMERSIONASA MEANSOFSIMULATINGMICROGRAVITY)NADDITION "IOSATELLITE WASLAUNCHEDIN  WEEKSBEFORETHEʄRSTMENWERETOLANDONTHE-OON WITHAMONKEYPASSENGER4HE ʅIGHTWASPLANNEDFORAFULLMONTH BUTTHEMONKEYWASBROUGHTDOWN ILLFROMLOSS OFBODYʅUIDS AFTERONLYDAYS)TDIEDSHORTLYAFTERLANDING$ESPITETHECONCERNTHAT THESAMEPROBLEMCOULDOCCURTOHUMANS THE!POLLOMISSIONSTOTHE-OONPROCEEDED ASPLANNED $URINGTHE!POLLOMISSIONS AMEDICALPROGRAMWASDEVELOPEDTHATWOULDMAKE PROVISIONFOREMERGENCYTREATMENTDURINGTHECOURSEOFTHEMISSIONINCASEASERIOUS ILLNESS OCCURRED )NDEED DURING THE ORBITAL ʅIGHTS OF -ERCURY AND 'EMINI IT WAS ALWAYSPOSSIBLETOABORTTHEMISSIONANDRECOVERTHEASTRONAUTWITHINAREASONABLE TIMESHOULDANIN ʅIGHTMEDICALEMERGENCYOCCUR4HISALTERNATIVEWASGREATLYREDUCED DURING !POLLO 4HE EVENTS OF !POLLO  SHOWED THAT THIS MEDICAL PROGRAM PROVED EFFECTIVE"IOMEDICALʄNDINGSOFTHE!POLLOPROGRAMREVEALEDADECREASEINPOSTʅIGHT EXERCISECAPACITYANDREDBLOODCELLNUMBER ALOSSOFBONEMINERAL ANDTHERELATIVELY HIGHMETABOLICCOSTOFEXTRA VEHICULARACTIVITY)NADDITION SYMPTOMSOFSPACEMOTION SICKNESSSUCHASNAUSEAANDVOMITING EARLIERDESCRIBEDBY3OVIETCOSMONAUTS WERE EXPERIENCED4HESEOBSERVATIONSRAISEDANOTHERCONCERNFORFUTUREHUMANSPACEʅIGHTS ANDTHEREFORECONSTITUTEDTHESTARTINGPOINTOFDETAILEDLIFESCIENCESINVESTIGATIONSIN THE3KYLABPROGRAMINTHEȀS 4HE533KYLAB&IGURE ANDTHE3OVIET3ALYUTSPACESTATIONSALLOWEDSCIEN TISTSTOCONDUCTINVESTIGATIONSONBOARDLARGEORBITINGFACILITIESDURINGMISSIONSLASTING UPTOMONTHS4HEYGAVEABASICPICTUREOFHOWTHEBODYREACTSANDADAPTSTOTHE SPACEENVIRONMENT4HENUMBEROFSUBJECTSWAS HOWEVER STILLLIMITED

)NTRODUCTIONTO3PACE,IFE3CIENCES



Figure 1.11. Actual Photograph (Left) and Drawing (Right) of the U.S. Skylab Space Station Showing the Orbital Module Laboratory with “Transparent” Walls and the Apollo Crew Return Vehicle. 4HE6OLUMEOFTHE,ABORATORY7AS!BOUTM. 4HE.INE!STRONAUTS6ISITING3KYLABINAND,OGGED!BOUT HOF 3CIENTIlC AND -EDICAL %XPERIMENTS $URING 4HREE -ISSIONS ,ASTING   AND DAYS 2ESPECTIVELY#REDIT.!3! 

Figure 1.12. Landing of the Space Shuttle at the Kennedy Space Center.#REDIT.!3! 

4HESPACESHUTTLEOR3PACE4RANSPORTATION3YSTEM 343 WHICHBEGANʅYINGIN  PROVIDEDTHEOPPORTUNITYTOTESTMORECREWMEMBERS!LSO ASTHEʄRSTSPACECRAFT THATCOULDBEUSEDAGAINANDAGAIN THESPACESHUTTLEHASPROVIDEDSPACELIFESCIENTISTS WITHAMOREREGULAROPPORTUNITYTOCONDUCTEXPERIMENTS ANDTOREPEATANDREʄNETHOSE EXPERIMENTS(OWEVER WITHTHESPACESHUTTLE OTHERCONCERNSAPPEARED)TWASREMARK ABLYDIFFERENTFROMTHEPREVIOUSSPACECRAFTBECAUSEITRETURNEDTO%ARTHBYLANDINGON ARUNWAY&IGURE  #RITICALISSUESEXISTEDCONCERNINGTHEABILITYOFCREWSTOPERFORMTHEVISUALAND MANUALTASKSINVOLVEDINPILOTINGANDLANDINGTHESHUTTLE ANDTHEIRCAPACITYTOACHIEVE UNAIDEDEGRESSAFTERLONGEXPOSURETOWEIGHTLESSNESS)TWASLATERFOUNDTHATTHEASTRO NAUT PILOTSWEREABLETOPILOTANDMANUALLYLANDTHESPACESHUTTLE ASLONGASTHEʅIGHT DURATION DID NOT EXCEED  WEEKS 3UCH CRITICAL ACHIEVEMENT WAS IN PART DUE TO THE



&UNDAMENTALSOF3PACE-EDICINE

DEVELOPMENTOFSPECIALSIMULATORSBUILTTOTRAINCREWSTOʅYANDLANDTHESPACESHUTTLE INWHATISNOWPOPULARLYTERMEDAȃVIRTUALREALITYȄSETTING)NFACT ASTRONAUTSRETURN INGFROMSHUTTLEMISSIONSREPORTEDTHATTHESIMULATIONSWERESOACCURATETHEYFELTTHEY HADʅOWNTHEMISSIONMANYTIMES  4ODAYȀSACCESSTOSPACE )NʅIGHTSBETWEENAND THESPACESHUTTLEHASREPEATEDLYDEMONSTRATED UNIQUECAPABILITIESASSPACETRANSPORTER REPAIRSHIP SCIENTIʄCPLATFORM ANDRESEARCH CENTER)TʄRSTACCOMPLISHEDITSROLEOFȃSHUTTLEȄBYRENDEZVOUSANDDOCKINGWITH-IR IN AFEWMONTHSAFTERTHEENDOF6ALERY0OLYAKOVȀS MONTHMISSION&ROM &EBRUARY  TO *UNE  .!3! SPACE SHUTTLES MADE  ʅIGHTS TO THE 2USSIAN SPACESTATION-IR AND53ASTRONAUTSSPENTSEVENRESIDENCIES ORȃINCREMENTS ȄON BOARD-IRSPACESHUTTLESALSOCONDUCTEDCREWEXCHANGESANDDELIVEREDSUPPLIESAND EQUIPMENT4HESPACESHUTTLEWASTHENTHEʄRSTSPACECRAFTTODOCKWITHTHE)33 IN -AY3INCETHEPERMANENTCREWOCCUPATIONOFTHE)33IN.OVEMBER THE SPACESHUTTLEHASENSUREDMOSTOFTHECREWTRANSPORT TOGETHERWITHTHE3OYUZ BETWEEN %ARTHANDTHE)33 -ORETHANFOURTIMESASLARGEAS-IR THE)33CONSISTSOFPRESSURIZEDMODULES WITHACOMBINEDVOLUMEOFAROUND M&IGURE 4HESEMODULESINCLUDE LABORATORIES DOCKINGCOMPARTMENTS AIRLOCKS NODES ANDLIVINGQUARTERS!SOF*ULY  OFTHESECOMPONENTSWEREALREADYINORBIT4HERESEARCHLABORATORIESINCLUDE THE2USSIAN:VEZDAAND2ASSVETMODULES THE53$ESTINYMODULE THE*APANESE+IBO MODULE ANDTHE%UROPEAN#OLUMBUSMODULE4HEREMAININGTWOLABORATORIESWAITING TOBELAUNCHEDARETHE2USSIAN.AUKAMODULEANDTHE%UROPEAN,EONARDOMODULE

Figure 1.13. The International Space Station.#REDIT.!3! 

)NTRODUCTIONTO3PACE,IFE3CIENCES



%ACH MODULE WAS OR WILL BE LAUNCHED EITHER BY THE SPACE SHUTTLE OR BY 0ROTON OR 3OYUZROCKETS)33ASSEMBLYWILLBECOMPLETEDBY BYWHICHPOINTTHE)33WILL HAVEAMASSINEXCESSOFMETRICTONS 4HE GRAVITY ENVIRONMENT ON THE STATION IS DESCRIBED AS ȃMICRO GRAVITY Ȅ AS THE WEIGHTLESSNESSISIMPERFECT4HISISCAUSEDBYFOURSEPARATEEFFECTSA THEDRAGRESULT ING FROM THE RESIDUAL ATMOSPHERE B VIBRATORY ACCELERATION CAUSED BY MECHANICAL SYSTEMSANDTHECREWC ORBITALCORRECTIONSBYTHEON BOARDGYROSCOPESORTHRUSTERS ANDD THEDISTANCEFROMTHEREALCENTEROFMASSOFTHE)33 .ORMALAIRPRESSUREONTHE)33ISK0APSI THESAMEASATSEALEVELON %ARTH4HETIMEZONEUSEDONBOARDTHE)33IS#OORDINATED5NIVERSAL4IME54# ALSO CALLED'-4 )NGENERAL THECREWWORKSHDAYONAWEEKDAY ANDHON3ATURDAYS WITHTHERESTOFTHETIMETHEIROWNFORRELAXATION GAMES ORWORKCATCH UP4HE)33 DOES NOT FEATURE A SHOWER )NSTEAD CREWMEMBERS WASH USING A WATER JET AND WET WIPES WITHSOAPDISPENSEDFROMATOOTHPASTETUBE LIKECONTAINER#REWSAREALSOPRO VIDEDWITHRINSELESSSHAMPOOANDEDIBLETOOTHPASTETOSAVEWATER4HEREARETWOSPACE TOILETSONTHE)33 LOCATEDIN:VEZDAAND$ESTINY -OSTOFTHESPACEFOODEATENBYSTATIONCREWSISFROZEN REFRIGERATED ORCANNED -ENUSAREPREPAREDBYTHEASTRONAUTS WITHTHEHELPOFADIETITIAN BEFORETHEIRʅIGHTTO THE)33%ACHCREWMEMBERHASINDIVIDUALFOODPACKAGESANDCOOKSTHEMUSINGTHE ONBOARD GALLEY WHICH FEATURES TWO FOOD WARMERS A REFRIGERATOR AND A WATER DIS PENSERTHATPROVIDESBOTHHEATEDANDUNHEATEDWATER$RINKSAREPROVIDEDINDEHY DRATEDPOWDERFORM ANDAREMIXEDWITHWATERBEFORECONSUMPTION$RINKSANDSOUPS ARESIPPEDFROMPLASTICBAGSWITHSTRAWS WHILESOLIDFOODISEATENWITHAKNIFEAND FORK WHICHAREATTACHEDTOATRAYWITHMAGNETSTOPREVENTTHEMFROMʅOATINGAWAY %ACHPERMANENTSTATIONCREWISGIVENASEQUENTIAL%XPEDITIONNUMBER%XPEDITIONS HAVEANAVERAGEDURATIONOFMONTHS%XPEDITIONS THROUGHȪCONSISTEDOFTHREE PERSONCREWSEXCEPTFOR%XPEDITIONS TOȪ WHICHLEDTOAREDUCTIONTOTWOCREW MEMBERSFOLLOWINGTHESPACESHUTTLE#OLUMBIADISASTER )N-AY %XPEDITION  WASTHEʄRST)33CREWOFSIX4HE)33ISTHEMOSTVISITEDSPACECRAFTINTHEHISTORYOF SPACEʅIGHT!SOF3EPTEMBER ITHADVISITORSINDIVIDUALS FROMDIF FERENTNATIONALITIES4ABLE -IRHADVISITORSINDIVIDUALS  %MERGENCY CREW RETURN VEHICLES WILL ALWAYS BE DOCKED WITH THE )33 WHILE IT IS INHABITED TOASSURETHERETURNOFALLCREWMEMBERS4HE3OYUZSPACECRAFT WHICHHASA CREWCAPACITYOFTHREE ISPRESENTLYUSED&OLLOWINGTHERETIREMENTOFTHESPACESHUTTLE ANUMBEROFOTHERSPACECRAFTAREEXPECTEDTOʅYTOTHESTATION4WO THE/RBITAL3CIENCES #YGNUSAND3PACE8$RAGONWILLʅYUNDERCONTRACTSWITH.!3! DELIVERINGCARGOTO THE )33 UNTIL AT LEAST  )N ADDITION THE /RION SPACECRAFT DEVELOPED AS A SPACE SHUTTLEREPLACEMENTASPARTOF.!3!ȀS#ONSTELLATIONPROGRAM WASRE TASKEDBY53 0RESIDENT"ARACK/BAMAON!PRIL  TOPROVIDELIFEBOATSERVICESTOTHE)33 )TISIMPORTANTTOREALIZETHATTHE)33ISFARMORETHANASCIENCEPLATFORMALONE4HE )33 CONSTITUTES A HIGHLY VISIBLE SIGNATURE IN THE SKY FOR HUMAN ENDEAVOR COURAGE SPIRIT AND INTERNATIONAL PEACEFUL COLLABORATION AND IT IS THE GREATEST TECHNOLOGICAL CHALLENGETHEHUMANRACEHASTACKLEDSOFAR4OALARGEPARTTHISWASTHEEARLYPOLITICAL MOTIVATIONTHATLEDTOITSCONCEPTION)NADDITION ANDLOOKINGMORETOWARDSTHEFUTURE THE)33PROVIDESTHEGATEWAYFORHUMANEXPLORATIONOFTHE3OLAR3YSTEM4HE)33 HAS ALSO THE POTENTIAL FOR BECOMING AN IDEAL TOOL TO SUPPORT EDUCATIONAL ACTIVITIES

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 Table 1.2.

International Space Station Statistics as of September 2010. 3OURCES HTTPSPACEKURSKNETRUCOSMOSENGLISHOTHERSISSSHT HTTPENWIKIPEDIAORGWIKI ,IST?OF?)NTERNATIONAL?3PACE?3TATION?VISITORS. Total Residents and Visitors Since Start of Assembly 4RIPS  &LYERS  7OMEN  )33CREWMEMBERS  4OURISTS  Flights Since Start of Assembly (1999) !MERICAN 2USSIAN

%UROPEAN *APANESE

3HUTTLE 0ROTON 3OYUZ 0ROGRESS !46 ( ))46

Space Walks (1999–2010) .UMBEROFASTRONAUTS .UMBEROF%6! 4OTALDURATIONMAN %6!HOURS

   

)NPARTICULAR EDUCATIONALPROGRAMSENCOURAGINGANDSUPPORTINGTHESTUDYOFSCIENCE MATHEMATICS TECHNOLOGY AND ENGINEERING CAN BE IMPLEMENTED ON BOARD THE )33 MAKING USE OF ITS FACILITIES AND RESOURCES /THER EDUCATION PROJECTS CAN BE IMPLE MENTEDTHATFOCUSNOTONLYONSCIENCEANDTECHNOLOGYBUTALSOONALARGERVARIETYOF SUBJECTS SUCHASLANGUAGES COMPOSITION ANDART )N!PRIL AN!MERICANENGINEERANDMILLIONAIREʅEWONA3OYUZANDSPENT DAYSONBOARDTHE)33(ISTRIPERUPTEDINACONTROVERSYWHEN.!3!ANDTHEOTHER)33 PARTNERSOBJECTEDTOATOURISTVISITINTHEMIDDLEOFACRITICALSERIESOFASSEMBLYOPERA TIONSATTHE)334HE)33PARTNERSRELUCTANTLYGAVETHEIRAPPROVALFORAVISITTHATWAS GOINGTOHAPPENWITHORWITHOUTTHEIRAPPROVAL INRETURNFORAPROMISEBYTHE2USSIAN 3PACE!GENCYTOMEETNEWSTANDARDSFORPAYINGVISITORSINTHEFUTURE"ETWEEN!PRIL AND/CTOBERSIXOTHERORBITALSPACETOURISTSʅEWTOANDFROMTHE)33ON 3OYUZSPACECRAFTTHROUGHTHESPACETOURISMCOMPANY 3PACE!DVENTURES FORACOST RANGINGFROMTOMILLION !SAMATTEROFFACT ORBITALȃSPACETOURISTSȄȃSPACEPARTICIPANTS ȄORȃCOMMERCIAL ASTRONAUTS Ȅ ACCORDING TO THE NEW TITLE AWARDED BY THE 53 &EDERAL !VIATION !DMINISTRATION HADALREADYʅOWNONSEVERALOCCASIONS!SENATOR ACONGRESSMAN A TEACHER ANDAPRINCEFROM3AUDI!RABIAHAVEʅOWNON53MISSIONS!REPORTER AN ENGINEERFROMACHOCOLATECOMPANY ANDGUESTSFROMALLIEDCOUNTRIESHAVEʅOWNON 3OVIET NOW2USSIAN SPACEMISSIONS"EFOREBEINGAFULL)33PARTNER %UROPETOOKTHE OPPORTUNITYOFAPAYINGVISITORONTHE3OYUZTOALLOWITSASTRONAUTSTOHAVEAREGULAR ACCESSTO-IRANDTHE)33FORWEEKATATIME THESO CALLEDȃ4AXIȄMISSIONS -ORE AFFORDABLE SPACE TOURISM WILL BE THE RESULT OF NEW VEHICLES THAT MAKE SUBORBITALʅIGHTSPEAKINGATANALTITUDEOFǻKM&IGURE 0ASSENGERSWILL EXPERIENCEǻMINOFWEIGHTLESSNESS AVIEWOFATWINKLE FREESTARʄELD ANDAVISTAOF

)NTRODUCTIONTO3PACE,IFE3CIENCES



Figure 1.14. Suborbital Spaceflight Will Typically Go Above 100 km, Which Is Considered the Beginning of Space and Thus Entitles the Passengers of These Flights To Be Called “Astronauts.v !LTHOUGH AT A -UCH ,OWER !LTITUDE4HAN THE )33 THE 3PACE 0ARTICIPANTS 7ILL "E!BLE TO %NJOY A 3PECTACULAR 6IEW OF %ARTH AND -ICROGRAVITY FOR A &EW -INUTES 4HEY 7ILL !LSO %XPERIENCE #ONSIDERABLE !CCELERATIONS $URING ,AUNCH AND 2E ENTRY 0RESUMABLY -ORE 3O 4HAN IN THE 3PACE3HUTTLE#REDIT!NSARI 80RIZE 

THECURVED%ARTHBELOW/N/CTOBER  3PACE3HIP/NE DESIGNEDBY"URT2UTAN OF3CALED#OMPOSITES WONTHE  !NSARI 80RIZE WHICHWASAWARDEDTO THEʄRSTPRIVATECOMPANYTHATCOULDʅYAVEHICLEATANALTITUDEOFKMTWICEWITHIN  WEEKS 4HE  KM ALTITUDE IS BEYOND THE +žRMžN ,INE THE ARBITRARILY DEʄNED BOUNDARYOFSPACE6IRGIN'ALACTIC ONEOFTHELEADINGSPACETOURISMGROUPS ISPLAN NING TO BEGIN PASSENGER SERVICE ABOARD THE 633 %NTERPRISE A 3CALED #OMPOSITES 3PACE3HIP4WO SPACECRAFT 4HE INITIAL SEAT PRICE WILL BE   BUT THAT PRICE IS EXPECTEDTOEVENTUALLYFALLTO 4ODATE OVER PEOPLEHAVEMADEDOWN PAYMENTSONBOOKINGS.ODOUBTABOUTIT SPACETOURISMISAREALITY ANDITȀSAGOOD ANDNECESSARYDEVELOPMENTFORTHEFUTUREOFHUMANSPACEEXPLORATION

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3URVIVINGTHE/DYSSEY

%ARLYPREDICTIONSOFTHERESPONSEOFHUMANSTOSPACEʅIGHTASSUMEDTHATSPACEADAPTA TIONWOULDBEANALOGOUSTOHUMANDISEASEPROCESSESRATHERTHANTONORMALPHYSIOLOGY 4HEPREDICTIONSMADEBYSCIENTISTSABOUTTHEABILITYOFHUMANSTOENDURESPACEʅIGHT WEREINDEEDDIRE$ESPITEGROUND BASEDSTUDIESPROVINGTHECONTRARY THEREWASTRUE CONCERN THAT THE G FORCES OF LAUNCH AND RE ENTRY ǻ G FOR THE EARLIEST SPACECRAFT WOULDRENDERHUMANPASSENGERSUNCONSCIOUS SEVERELYIMPAIRED OREVENDEAD4HE MYSTIQUEOFTHISALIENENVIRONMENTWASSOGREATTHATMANYFEAREDAPSYCHOTICBREAK DOWNWHENHUMANSWOULDʄNDTHEMSELVESDISCONNECTEDFROMANDLOOKINGDOWNON MOTHER%ARTH3OMEPHYSICIANSVOICEDCONCERNSTHATBODILYFUNCTIONSINWEIGHTLESS NESSMIGHTSUFFERFROMALONGLISTOFCALAMITIESSWALLOWING URINATION ANDDEFECATION WOULDBEIMPAIREDORIMPOSSIBLEINTHEABSENCEOFGRAVITYALTHOUGHANYONEWHOHAS EVERSWALLOWEDWHILESTANDINGONTHEIRHEADHANGINGUPSIDEDOWNCOULDHAVEPROVEN OTHERWISE THEBOWELSWOULDNOTWORKWITHOUTGRAVITYTHEHEARTMIGHTCAVITATELIKE A PUMP OR BEAT SO IRREGULARLY AS TO CAUSE PROBLEMS SLEEP WOULD BE IMPAIRED AND MUSCLES INCLUDINGTHEHEART WOULDBECOMESOWEAKENEDASTOPROHIBITRETURNTO%ARTH ;#HURCHILL = 4HEʄRSTSPACEMISSIONSSHOWED HOWEVER THATWITHTHEPROPERPROTECTION HUMANS COULDSURVIVEAJOURNEYINTOSPACE"IOMEDICALCHANGESHAVEBEENOBSERVEDDURING SPACEʅIGHT DUETOTHEEFFECTSOFMICROGRAVITY BUTALSOTOOTHERPHENOMENON SUCHAS HIGHLAUNCHANDRE ENTRYGRAVITATIONALFORCES RADIATIONEXPOSURE ANDPSYCHOLOGICAL STRESS 4O ILLUSTRATE OF WHAT WE DO KNOW AT THIS POINT COLLEAGUE AND FRIEND 3USANNE #HURCHILL INONEOFHERLECTURESATTHE)NTERNATIONAL3PACE5NIVERSITY USEDTODESCRIBE THESPACEJOURNEYOFANHYPOTHETICALSPACETRAVELERWHOEXPERIENCESALLOFTHEKNOWN PROBLEMS7EWILLUSETHESAMEAPPROACHBELOW 3O LETUSTAKEAJOURNEYWITHOURHYPOTHETICALASTRONAUT3HEISINEXCELLENTHEALTH ANDFULLYTRAINEDFORTHERIGORSOFHER MONTHINCREMENTONBOARDTHE)33,AUNCH OCCURSASANTICIPATEDACOUPLEOFHOURSBEFORELAUNCHSHEHADJOINEDTHEOTHERSLYING DOWNINTHESEATSOFTHESPACESHUTTLE STRAPPEDIN FEETABOVEHEAD ASINTHEEARLY -ERCURY 'EMINI OR!POLLOLAUNCHES"UTTHERE THESIMILARITYENDS&ORDURINGSHUT TLELIFT OFFSHEDOESNOTUNDERGOTHEUNPLEASANTGRAVITYLOAD WHICHWENTASHIGHASG ONEARLIERʅIGHTS)NSTEAD SHEEXPERIENCESGONLYTWICE4HEʄRSTTIMECOMESAND GOESQUICKLYNEARTHE MINMARK JUSTBEFORETHETWOSOLIDROCKETBOOSTERSBURNOUT ANDDROPBYPARACHUTEINTOTHE!TLANTIC/CEAN4HEʄNAL GLOADCOMESMINLATER ANDLASTSFORAMINUTE,ESSTHANMINFROMLIFT OFF SHEʄNDSHERSELFʅOATINGINTHE WEIGHTLESSNESSOFSPACE 7ITHOUTWARNING HOWEVER SHESUDDENLYVOMITSANDISOVERWHELMEDWITHINTENSE SYMPTOMSOFMOTIONSICKNESSNAUSEA ASENSEOFDIZZINESS ANDDISORIENTATION(ER SYMPTOMSBECOMEWORSTWHENSHEMOVESABOUTINTHECABINORSEESONEOFHERFELLOW CREWMEMBERSʅOATINGUPSIDE DOWN3HEISUNABLETOKEEPFOODDOWNANDREJECTSEVEN

 4HISWASONEREASONWHYTHEEARLIESTSPACECRAFTWERETOTALLYAUTOMATIC WITHNOCONTROLSFORADISORIENTED ORȃCRAZEDȄPILOTTOUSEINDEPENDENTLY

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WATERTODRINK SOSHEQUICKLYDEHYDRATES3HEISCONCERNEDTHATSHECOULDNOTHELPTHE RESTOFHERCREWWITHTHERENDEZVOUSPROCEDURESOFTHESHUTTLEWITHTHE)33 BECAUSE LOOKINGOUTOFTHEWINDOWSTRIGGERSMORESYMPTOMS3HETAKESSOMEPILLSANDISGET TINGREADYFORSLEEP(OWEVER WHENLOOKINGINTHEMIRRORABOVETHEWASHBASIN SHE REALIZESTHATHEREYESSEEMSMALLER HERFACEISROUNDANDPUFFY&IGURE ANDHER NECKVEINSAREBULGING4HEGOODNEWSISTHATHERWRINKLESHAVEDISAPPEAREDANDSHE LOOKSYOUNGER7HENUNDRESSING SHENOTICESTHATHERLEGSLOOKLIKESTICKS3HETRIESTO SLEEPBUTHASAPERSISTENTBACKACHE ADEʄNITEFEELINGOFSINUSCONGESTION ANDKEEPS WAKINGTODISCOVERTHATHERARMSAREʅOATINGABOVEHERHEAD3ODISCONCERTING
7HENSHEWAKESUPANDDRESSES SHEʄNDSHERCLOTHESTOOSHORT"ECAUSEOFTHE ABSENCEOFPERCEIVEDGRAVITY HERVERTEBRATEDISKSARELESSCOMPRESSED MAKINGHER HEIGHTINCREASEBYǻCM&IGURE ANDCAUSINGCONTINUINGBACKPAIN!LSO ASA RESULTOFTHEʅUIDSHIFTWHICHISALSORESPONSIBLEFORHERPUFFYFACEANDȃCHICKENȄ LEGS HERWAISTLINEHASSHRUNKABOUTCM ANDSHEMUSTTIGHTENTHEBANDSOFHERPANTS (ERSHOESHAVEALSOBECOMETOOLOOSE 7ITHINACOUPLEOFDAYS THEMOTIONSICKNESSSYMPTOMSBEGINTOSUBSIDE THOUGH HERFACEANDLEGSREMAINCHANGED(ERPOSTURE TOO ISDIFFERENT BUTNOTFORTHEBETTER *OINTSGOTOTHEIRMIDPOINTINZEROGRAVITY SOTHATTHEHIPSANDKNEESAREBENTINTOA SLIGHTCROUCH(ERARMSTENDTOʅOATINFRONTOFHERUNLESSSHECONSCIOUSLYHOLDSTHEM DOWN7HENSHESITSATAWORKBENCH SHEHASTOSTRAPHERSELFINPLACE%VENSO HER SEATEDPOSTUREISTOLEANBACK.EVERTHELESS SHELEARNSTOMOVEAROUNDINWEIGHTLESS NESSBYGENTLYPUSHINGANDPULLINGHERBODYWITHHERʄNGERTIPS 2ENDEZVOUSANDTRANSFERTOTHE)33OCCURWITHOUTINCIDENT ANDSHESTARTSTOSETTLE FORA MONTHSTAYONBOARDWITHHERTWOFELLOWCREWMATES0ERSONALHYGIENEISLIMITED TOȃSPONGEȄBATHINGFOODBECOMESBLANDTASTING ANDSHEMUSTADDSPICESFORINTEREST

Figure 1.15. An Example of “Puffy Face.v4HE.ORMAL&ACEOFAN!STRONAUTON%ARTHLeft )S #ONTRASTEDWITH(IS3WOLLEN ,OOKING&ACEIN3PACERight #REDIT.!3! 



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Figure 1.16. Diagram Showing the Increase in the Height of an Astronaut During the First Hours of a Space-Flight.!DAPTEDFROM4HORNTONAND-OORE;]).

4HEREAREEXPERIMENTSTOMONITORANDSEVERALHOURSOFEXERCISEDAILYONTHETREADMILL ORCYCLEERGOMETER!FTERAFEWWEEKS HOWEVER THEROUTINEBECOMESBORINGANDITGETS HARDERANDHARDERTOKEEPUPWITHTHEEXERCISE4HEMORESHELOOKSOUTOFTHEWINDOW THE MORE SHE LONGS FOR THE SOUNDS OF RAIN AND WIND AND THE SMELL OF ʅOWERS 4HE OBJECTSOUTSIDETHESTATIONLOOKȃUNREALINCLARITYȄ(OWEVER WHENSHECLOSESHEREYES SHE EXPERIENCES LIGHT ʅASHES ESPECIALLY WHEN THE )33 ʅIES OVER THE 3OUTH !TLANTIC !NOMALY4HECREWSTARTSTOARGUEABOUTTHESMALLESTTHINGS/NEPLANNEDSPACEWALK HAS TO BE CANCELED BECAUSE OF A PERSISTENT IRREGULAR HEARTBEAT IN ONE CREWMEMBER 3INCETHATINCIDENT THISCREWMEMBERSEEMSTOBEWITHDRAWINGFROMTHEOTHERS4HE WEEKLYVIDEOCONFERENCESWITHFAMILYANDFRIENDSAREEAGERLYANTICIPATED BUTSHEWON DERSWHYTHEREHASBEENNOCOMMUNICATIONFROMHERYOUNGESTCHILDFORSEVERALWEEKS (ASSOMETHINGHAPPENED!NXIETYARISES ANDSHEHASAPERSISTENTPAININHERLOWER ABDOMEN WHICH IFITCONTINUES MIGHTPROMPTANEMERGENCYEVACUATIONTO%ARTH "UTATLASTTHETIMETORETURNAPPROACHES!NINTERESTINGMIXTUREOFEXCITEMENTAND ANXIETYPERVADESTHECREW6ISIONSOFFAVORITEFOODSANDWHATTODOʄRSTARETHEMAIN TOPICSOFCONVERSATION9ET THEGROUPHASBECOMESOʄRMLYAPARTOFEACHOTHERTHAT THETHOUGHTSOFREINTEGRATINGINTO%ARTHȀSSOCIETYAREINTIMIDATING"UTATLASTTHECREW ISONITSWAYHOME7HENDONNINGHERRE ENTRYSPACESUIT SHEREALIZESITISTOOTIGHT BECAUSESHEHASGROWNAFEWCENTIMETERS$URINGTHERE ENTRYINTO%ARTHȀSATMOSPHERE OURTRAVELEREXPERIENCESDISORIENTATIONAGAINWHENSHETILTSORROLLSHERHEAD!FTER LANDING SHEREPORTSANUNBELIEVABLESENSEOFȃHEAVINESSȄANDʄNDSHERSELFUNABLETO STANDUPUNASSISTEDFROMHERSEAT MUCHLESSWALKINGDOWNTHESTAIRS(ERHEARTIS BEATINGFASTSHESWEATSANDALMOSTFAINTS %VENAFTERSEVERALDAYSOFREHABILITATION BALANCEISPOORANDWALKINGUNCOORDI NATED-USCLEWEAKNESSISVERYEVIDENTSHEQUICKLYFEELSSHORTOFBREATHANDISCON STANTLY THIRSTY 7EIGHT LOSS THAT OCCURRED IN SPACE IS RAPIDLY DISAPPEARING BUT HER PHYSICIAN TELLS HER THAT SHE HAD LOST MUCH OF BONE DENSITY IN HER HIPS AND THAT HER IMMUNESYSTEMSEEMSTOBEIMPAIRED.OWSHEISCONCERNEDBECAUSESHEREMEMBERS THATTHEVARIOUSBACTERIALCOLONIESTHEYWERESTUDYINGONBOARDTHE)33LABORATORIES SHOWEDEXPLOSIVEGROWTHRATES
3EVERALMONTHSLATER THOUGH ALLHERBODYFUNCTIONS SEEMTOHAVERE ADAPTEDTO%ARTHȀSGRAVITY

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4HISSTORYISNOTMEANTTODISCOURAGEANYONEFROMWANTINGTOBEANASTRONAUT)N REALITY NOTALLPEOPLEEXPERIENCEALLOFTHEADVERSEEFFECTSOFSPACEʅIGHT)TISRATHER MEANTTOSHOWHOWLITTLEWEREALLYKNOWABOUTTHEHUMANBODYȀSRESPONSETOSPACE ʅIGHTANDHOWVERYDANGEROUSTHISNEWENVIRONMENTCANBE4HEINTERPRETATIONSFOR THE OBSERVED PHYSIOLOGICAL AND PSYCHOLOGICAL CHANGES DURING SPACEʅIGHT WILL BE DETAILEDIN#HAPTERSǻOFTHISBOOK 

,IFESUPPORTSYSTEMS

3PACEʅIGHTINCLUDESCONDITIONSSUCHASVACUUM EXTREMETEMPERATURES NOISEMOSTLY DUETOTHELIFESUPPORTSYSTEMS ANDRADIATION0ROTECTINGHUMANSFROMTHESEHARMFUL CONDITIONSREQUIRESTHEUSEOFLIFESUPPORTEQUIPMENTANDTECHNOLOGIESSUCHASSPACE SUITS PRESSURIZEDANDISOLATEDLIVINGQUARTERS ANDRADIATIONSHIELDING )NADDITION CERTAINBASICPHYSIOLOGICALNEEDSMUSTBEMETFORHUMANBEINGSTOSTAY ALIVE/N%ARTH THESENEEDSAREMETBYOTHERLIFEFORMSINCONJUNCTIONWITHCHEMICAL PROCESSESTHATEFFECTIVELYUSEHUMANWASTEPRODUCTSINCONJUNCTIONWITHENERGYFROM THE3UNTOPRODUCEFRESHSUPPLIESOFFOOD OXYGEN ANDCLEANWATER)NTHEARTIʄCIAL ENVIRONMENT OF A SPACECRAFT THESE MATERIALS MUST BE PROVIDED AND HUMAN WASTES REMOVED WITHOUTRELYINGONTHENATURALRESOURCESOF%ARTHȀSBIOSPHERE 4ODATE SPACEMISSIONSHAVEUSEDASIMPLEȃOPENȄSYSTEM BRINGINGALONGALLNEC ESSARYFOOD WATER ANDAIRFORTHECREWANDVENTINGWASTEPRODUCTSINTOSPACEORCOL LECTINGANDSTORINGTHEMFORRETURNTO%ARTH7HENTHEPOINTISREACHEDWHEREITISNO LONGERCOSTEFFECTIVEORLOGISTICALLYPOSSIBLETORE SUPPLYTHESPACECRAFTORHABITATWITH WATER ATMOSPHERE ANDFOOD WAYSMUSTBEFOUNDTORECYCLEALLTHESECOMPONENTS 4HIS RECYCLING OF MATERIAL IS REFERRED TO AS A ȃCLOSEDȄ SYSTEM AND CAN BE ACHIEVED USINGPHYSICAL CHEMICALSYSTEMS ORBETTER USINGBIOLOGICALSYSTEMS&IGURE 

Figure 1.17. A Closed Ecological Life Support System Employs Biological Components and Uses Higher Plants.(IGHER0LANTS!RE%ASILY$IGESTIBLEAND!RE#USTOMARY 3OURCES OF (UMAN &OOD "ESIDES 0RODUCING &OOD 4HEY !LSO 2EMOVE #ARBON $IOXIDE FROM THE !TMOSPHERE 0RODUCE /XYGEN AND 0URIFY 7ATER 4HROUGH THE 0ROCESSOF2ESPIRATION#REDIT0HILIPPE4AUZIN 



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4HINKOFTHEHUMANBODYASASEALEDBOXWITHONEPIPEINANDONEPIPEOUT)NGO OXYGEN/ WATER ANDFOODOUTCOMESOLIDANDLIQUIDWASTES BACTERIA ANDCARBON DIOXIDE#/ 4HEOUTLETPIPEISFEDINTOASECONDSEALEDBOX THECLOSEDORCON TROLLED ECOLOGICALLIFESUPPORTSYSTEM#%,33 4HE#%,33MUSTBEASȃMAGICALȄAS THEʄRST FORITMUSTTRANSFORMTHESEBY PRODUCTSOFTHEBODYINTOFRESHSUPPLIESAND PIPETHEMBACK;#OLLINS = 4RYINGTORECREATETHECYCLESOFNATUREINARELATIVELYSMALLVOLUMEISAGREATTECHNI CALCHALLENGE0LANTSȃBREATHEȄ#/ANDȃEXHALEȄ/ SOINABROADSENSEHUMANWASTES AREUSEDBYPLANTSANDVICEVERSA"UTINNATURETHENUTRIENTS AIR WATER ANDENERGYARE FREELYAVAILABLE)NA#%,33SYSTEMALLOFTHESEELEMENTSMUSTBEIMPORTEDANDCARE FULLY MANAGED IN A CLOSED CYCLE 4HERE ARE CRITICAL QUESTIONS BEING ADDRESSED FOR #%,33 DURING HUMAN MISSIONS &OR EXAMPLE (OW FAR CAN WE REDUCE RELIANCE ON EXPENDABLES(OWWELLDOBIOLOGICALANDPHYSICAL CHEMICALLIFESUPPORTTECHNOLOGIES WORKTOGETHEROVERLONGPERIODSOFTIME)SAȃSTEADYSTATEȄCONDITIONEVERACHIEVED WITHBIOLOGICALSYSTEMS(OWDOVARIOUSCONTAMINANTSACCUMULATE ANDWHATARETHE LONG TERMCLEANLINESSISSUES%VENTUALLY INTHECASEOFINTERPLANETARYMISSIONS ISIT POSSIBLETODUPLICATETHEFUNCTIONSOF%ARTHINTERMSOFHUMANLIFESUPPORT WITHOUTTHE BENEʄTOF%ARTHȀSLARGEBUFFERSǻOCEANS ATMOSPHERE LANDMASS(OWSMALLCANTHE REQUISITEBUFFERSBEANDYETMAINTAINEXTREMELYHIGHRELIABILITYOVERLONGPERIODSOF TIMEINAHOSTILEENVIRONMENT%CKART;=HASADDRESSEDMOSTOFTHESEQUESTIONS 7EWILLSUMMARIZETHEMIN#HAPTER

 #HALLENGESFACINGHUMANSINSPACE  !STRONAUTSȀHEALTHMAINTENANCE !S IT WILL BE DETAILED IN THE FOLLOWING CHAPTERS EXPOSURE TO MICROGRAVITY AND THE SPACE ENVIRONMENT HAS IMPORTANT MEDICAL AND HEALTH IMPLICATIONS INCLUDING BONE LOSSMATRIXANDMINERALS INCREASEDCANCERRISKFROMSPACERADIATION SPATIALDISORI ENTATION ORTHOSTATICHYPOTENSION ANDMANYOTHERS/NEOFTHEPRIMARYOBJECTIVESOF SPACE LIFE SCIENCES IS TO ENSURE THE HEALTH OF CREWMEMBERS WORKING ON BOARD THE SPACECRAFTANDINTHEHOSTILEENVIRONMENTOUTSIDETHEIRVEHICLES2ESPONSIBILITIESOF THE OPERATIONAL MEDICAL PROGRAM INCLUDE PREʅIGHT ACTIVITIES SUCH AS SCREENING AND SELECTINGNEWASTRONAUTCANDIDATES HEALTHSTABILIZATION IN ʅIGHTACTIVITIESSUCHASTHE ADMINISTRATIONOFCOUNTERMEASURESANDMEDICALCARE ANDPOSTʅIGHTPROCEDURESSUCH ASRESCUEAFTERANEMERGENCYLANDINGORREHABILITATIONFORAPROMPTRETURNOFCREW MEMBERSTOʅIGHTSTATUS;.ICOGOSSIANAND0ARKER "ARRATTAND0OOL =  0REʅIGHT 4HE MINIMAL MEDICAL CRITERIA FOR THE SELECTION OF ASTRONAUTS ARE DIFFERENT FOR THOSE ASTRONAUTSWHOACTUALLYPILOTTHEVEHICLEPILOTS THOSEWHOSUPPORTONBOARDOPERA TIONSANDPERFORMEXTRA VEHICULARACTIVITIESMISSIONSPECIALISTS ANDTHOSEPASSEN GERSWHOJUSTȃPARTICIPATEȄEITHERASPOLITICIANS JOURNALISTS ORTOURISTSSEE#HAPTER 3ECTION  "ASEDONTHEKNOWLEDGEOFSPECIʄCHEALTHRISKFACTORSASSOCIATEDWITHSPACEʅIGHT APPROPRIATEANDPROVENTESTSAREUTILIZEDINSELECTINGTHEASTRONAUTS!NNUALMEDICAL

)NTRODUCTIONTO3PACE,IFE3CIENCES



EVALUATIONSARETHENPERFORMEDTOIDENTIFYANDCORRECTMEDICALRISKSTOMAINTAINHEALTH PROVIDE CERTIʄCATION FOR ʅIGHT DUTIES AND ENSURE CAREER LONGEVITY 4HESE TESTS MAY INCLUDEFURTHERCLINICALEVALUATION EG USINGSTATE OF THE ARTIMAGERYTECHNIQUES OR ʄTNESSASSESSMENTSINORDERTOPRESCRIBEINDIVIDUALIZEDEXERCISEPROGRAMSANDPROVIDE ONE ON ONEPREʅIGHTANDPOSTʅIGHTCONDITIONINGACTIVITIES"OTHSELECTIONANDPERI ODICMEDICALEVALUATIONSRELYONTHEACCEPTEDGROUND BASEDSTANDARDSOFPREVENTIVE MEDICINE HEALTHMAINTENANCE ANDMEDICALPRACTICE4HESESTANDARDSAREREVISEDONA PERIODICBASISTOENSURETHATTHEYAREFAIRANDAPPROPRIATETOMEETTHENEEDSOFHUMAN SPACEʅIGHT $URINGPREʅIGHTTRAINING THEPRIMARYEMPHASISOFMEDICALSUPPORTISONPREVEN TION&OREXAMPLE THEPURPOSEOFTHE#REW(EALTH3TABILIZATIONPROGRAMISTOPREVENT ʅIGHTCREWSFROMEXPOSURETOCONTAGIOUSILLNESSJUSTBEFORELAUNCH!PREʅIGHTQUAR ANTINELIMITSACCESSTOʅIGHTCREWDURINGDAYSJUSTPRIORTOLAUNCH%VENBEFORETHIS PERIOD THEHEALTHOFANACTIVEDUTYCREWMEMBERFAMILYISOFCRITICALIMPORTANCE AND FACTORSSUCHASINFECTIOUSDISEASEANDSTRESSAFFECTINGACREWMEMBERFAMILYMAYHAVE SERIOUS ADVERSE EFFECTS ON THE CREWMEMBER HEALTH AND PERFORMANCE AS WELL AS THE HEALTHANDPERFORMANCEOFOTHERCREWMEMBERS-EDICALANDDENTALCAREISPROVIDEDTO THECREWMEMBERȀSIMMEDIATEFAMILYBYANONSITEʅIGHTMEDICALCLINIC ASLONGASTHE CREWMEMBERISELIGIBLEFORASSIGNMENTTOASPACEʅIGHTMISSION #REWMEMBERS ARE ALSO TRAINED IN THE USE OF SPECIAL COUNTERMEASURES TO OFFSET SPACEʅIGHTPHYSICALDECONDITIONINGANDINMEDICALMONITORINGANDCLINICALPRACTICE PROCEDURES-EDICALTRAININGFORTHECREW MEDICALSUPERVISIONOFMISSIONPLANNING SCHEDULES PAYLOADS EXERCISE TRAINING CONDITIONING AND OTHER HEALTH MAINTENANCE ACTIVITIESAREALLPARTOFTHEPREʅIGHTPERIOD  )N ʅIGHT 4HEPRIMARYEMPHASISOFIN ʅIGHTMEDICALSUPPORTISONHEALTHMAINTENANCE(EALTH MONITORING AND MEDICAL INTERVENTION COUNTERMEASURES TO BODILY FUNCTION DECONDI TIONING ANDENVIRONMENTALMONITORINGINSUREACOMPREHENSIVEPROGRAMTAILOREDTO CREW AND MISSION NEEDS AND FOR THE PERIODIC ASSESSMENT OF CREW MEDICAL STATUS INCLUDINGTHEIDENTIʄCATIONOFPOTENTIALANDUNEXPECTEDHEALTHRISKS !MONG THESE POTENTIAL HEALTH RISKS ARE THE LEVELS OF ACCELERATION VIBRATION AND NOISEDURINGLAUNCH THEEXPOSURETOTOXICSUBSTANCESANDPRESSURECHANGES ANDTHE RISK DUE TO RADIATION 7ITH THE POSSIBLE EXCEPTION OF THE IMMUNE SYSTEM BODILY CHANGESTHATOCCURAFTERENTERINGMICROGRAVITYREPRESENTNORMALHOMEOSTATICRESPONSES TOANEWENVIRONMENT4HEBODYȀSCONTROLSYSTEMSRECOGNIZETHELACKOFGRAVITYAND BEGINTOADAPTTOTHISUNIQUESITUATION NOTREALIZINGTHATTHEULTIMATEPLANISTORETURN TO  G AFTER A TRANSIENT VISIT TO MICROGRAVITY )N ʅIGHT TYPICAL ADAPTIVE AND PATHO PHYSIOLOGICALCHANGESOCCURINTHEHEARTANDBLOODVESSELSDYSRHYTHMIAS MUSCLES ATROPHY BONESDENSITYLOSS FRACTURES RENALSTONES NERVOUSSYSTEMDISORIENTATION ANDNAUSEA ANDINTHEIMMUNESYSTEMINFECTION %XTRA VEHICULARACTIVITIES%6! ALSOCALLEDSPACEWALKS MAYALSOBERESPONSIBLEFORSTRAINONMUSCLESANDBONESAND DECOMPRESSION RELATEDDISORDERS 0SYCHO SOCIOLOGICALISSUESBECOMEINCREASINGLYMOREIMPORTANTASSPACEMISSIONS BECOME LONGER AND SPACEʅIGHT TEAMS BECOME LARGER AND MORE HETEROGENEOUS 4HE ISOLATED CONʄNED AND HAZARDOUS ENVIRONMENT OF SPACE CREATE STRESS BEYOND THAT



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N ORMALLY ENCOUNTERED ON %ARTH EVEN WHEN TRAINING FOR A SPACE MISSION %XTENDED DURATIONMISSIONSPLACEANEVENGREATERSTRESSONINDIVIDUAL INTERPERSONAL ANDGROUP RELATIONS FOR ASTRONAUT CREWS BETWEEN ASTRONAUT CREWS AND GROUND CONTROL AND ON ASTRONAUTFAMILIES#URRENTCOUNTERMEASURESFOCUSPRIMARILYONTHEINDIVIDUAL MIS SIONCREW ANDTOSOMEEXTENTTHEFAMILIESOFMISSIONCREWS BYPROVIDINGPSYCHOLOGI CAL TRAINING AND SUPPORT THROUGH IN ʅIGHT COMMUNICATIONS &INALLY FOR SPACEʅIGHT MISSIONS EMPHASIS IS NOT ONLY ON HEALTH MAINTENANCE DISEASE PREVENTION AND ENVIRONMENTALISSUES BUTALSOONTHEPROVISIONOFMEDICALCARETOMANAGEPOSSIBLE ILLNESSESANDINJURIES  0OSTʅIGHT 4HEPRIMARYEMPHASISOFPOSTʅIGHTMEDICALSUPPORTISMEDICALCARE$URINGRETURNTO %ARTH PILOTINGTASKSARECHALLENGEDBYTHEPRESENCEOFGFORCESINDECONDITIONEDINDI VIDUALS&IGURE !FTERNOMINALLANDING ASTRONAUTSOFTENEXHIBITDIFʄCULTIESIN STANDING APHENOMENONKNOWNASPOSTʅIGHTORTHOSTATICINTOLERANCESEE#HAPTER 3ECTION ANDWALKING4HESEDIFʄCULTIESCOULDPROVEDRAMATICINTHECASEOFANON NOMINALLANDINGWHERETHECREWMAYBEREQUIREDTOSUDDENLYEGRESSTHEVEHICLEWITH NOHELPFROMGROUNDSUPPORT !STRONAUTSMUSTHAVECAREERLONGEVITY NORMALLIFEEXPECTANCY WITHREHABILITATION ANDRECOVERYCAPABILITIESAVAILABLEUPONTHEIRRETURNFROMSPACEʅIGHT!FTERLANDING HEALTHMONITORINGANDPHYSICALREHABILITATIONAREPERFORMEDTOACCELERATETHERETURNOF CREWMEMBERSTONORMAL%ARTH BASEDDUTIES!NIMPORTANTFACTORTOTAKEINTOACCOUNT ISTHERETURNTOʅIGHTSTATUSFORPILOTASTRONAUTS 4HEREISALARGECATALOGOFREPORTEDPOSTʅIGHTSYMPTOMSCAPTUREDINTHEMISSION MEDICALDEBRIEFSTHATARECOLLECTEDAFTERASPACEMISSIONTHROUGHINTERVIEWSBETWEEN THEASTRONAUTSANDCREWʅIGHTSURGEON!FTEREVERYSPACESHUTTLEMISSION A.!3!

Figure 1.18. Direction of g Forces Experienced During Landing in a Soyuz Capsule (Left) and the Space Shuttle (Right). ,OWER G &ORCES !RE 4OLERATED 7HEN $IRECTED !LONG THE "ODY ,ONGITUDINAL !XIS 'Z IN A $IRECTION 0ARALLEL TO THE "IG "LOOD 6ESSELS#REDIT0HILIPPE4AUZIN 

)NTRODUCTIONTO3PACE,IFE3CIENCES



ʅIGHTSURGEONHOLDSAMEDICALDEBRIEFWITHEACHCREWMEMBERONTHEDAYOFLANDING ANDTHENDAYSLATER3TANDARDIZEDDEBRIEFFORMSAREUSEDDURINGTHESEMEETINGS AT WHICHTIMETHEPHYSICIANANDCREWMEMBERDISCUSSPRE IN ANDPOSTʅIGHTMEDICAL ISSUES4HECREWMEMBERSAREINTERVIEWEDABOUTTHEIREXPERIENCES USINGBOTHOPEN ENDEDANDSPECIʄCQUESTIONS)NFORMATIONFROMTHESEDEBRIEFSISAVAILABLEINADATA BASE KNOWN AS THE ,ONGITUDINAL 3TUDY OF !STRONAUT (EALTH ,3!(  .!3! ʅIGHT SURGEONSOFTHE&LIGHT-EDICINE#LINICAT.!3!*OHNSON3PACE#ENTERPROVIDETHE INTERFACE WITH THE ,3!( WHICH IS A LONG TERM PROGRAM INVESTIGATING WHETHER THE UNIQUE OCCUPATIONAL EXPOSURES OF ASTRONAUTS ARE ASSOCIATED WITH INCREASED HEALTH RISKS 3UCH STUDIES ARE PARTICULARLY RELEVANT REGARDING THE ISSUE OF RADIATION EXPOSURE 

%NVIRONMENTALHEALTHDURINGSPACEMISSIONS

$URINGSPACEMISSIONS MEDICALCAREDOESNOTONLYFOCUSONHEALTHMAINTENANCEAND DISEASEPREVENTION BUTALSOONENVIRONMENTALISSUES3PACECRAFTARECLOSEDCOMPART MENTS AND THEREFORE STANDARDS FOR AIR WATER MICROBIOLOGY TOXICOLOGY RADIATION NOISE ANDHABITABILITYMUSTBEESTABLISHED)N ʅIGHTENVIRONMENTALMONITORINGSYS TEMSAREAVAILABLETOPREVENTCREWEXPOSURETOTOXICOLOGICALANDMICROBIALCONTAMI NATIONOFINTERNALAIR WATER ANDSURFACESTORADIATIONSOURCESFROMWITHINANDEXTERNAL TOTHESPACECRAFTANDTOVIBRATIONANDNOISE4HESESYSTEMSMUSTHAVENEARREAL TIME AND ARCHIVAL SAMPLING AND PROVIDE A MECHANISMTO ALERT CREWMEMBERS WHEN MEA SUREDVALUESAREOUTSIDEACCEPTABLELIMITS (ABITABILITYOFASPACECRAFTISVITALLYIMPORTANTTOTHECREWȀSHEALTH WELLBEING ANDPRODUCTIVITY ESPECIALLYASMISSIONDURATIONINCREASES(ABITABILITYISSUESREGARD INGTHEHUMANPRESENCEINSPACEINCLUDESHUMANFACTORDESIGNCONSIDERATIONSCOL ORS EQUIPMENT LAYOUT AND HARDWARE DESIGN ADEQUATE AND ERGONOMICALLY CORRECT WORK AND LIVING VOLUME WITH SIMILARLY ADEQUATE STOWAGE VOLUME !REAS MUST BE DESIGNEDTHATALLOWFORRESTFULSLEEPANDPERSONALSPACE WITHADEQUATELIGHTINGAND EXTERIOR VIEWS 3CHEDULES MUST PRODUCE INTERESTING WORK WITH SUFʄCIENT REST AND RECREATIONPERIODSTOAVOIDCHRONICFATIGUE)DEALLY EACHCREWMEMBERSHOULDHAVE PRIVATETIMEANDPHYSICALSPACEFORʄTNESSANDRECREATION INORDERTOKEEPHISHER MOTIVATION 4IMEANDRESOURCESARESETASIDEFORPERSONALHYGIENEANDSANITATIONSEE#HAPTER 3ECTION )NADDITION AHEALTHY PALATABLEVARIETYOFFOODANDBEVERAGEMUSTBE PROVIDED4ABLE 4HEDAILYFOODSUPPLYTOTALSAHIGH CAL PLUSSNACKS4HE MEALSALSOATTEMPTTOCOMPENSATEFORTHEBODYȀSTENDENCYTOLOSEESSENTIALMINERALSIN MICROGRAVITY SUCHASPOTASSIUM CALCIUM ANDNITROGEN !TTHESAMETIME THEMEALSMUSTBEATTRACTIVE NOTLIKETHEEARLYMISSIONSWHEN ASTRONAUTSHADTOSUCKTHEIRMEALSOUTOFȃTOOTH PASTEȄTUBESORPLASTICBAGSWITHOUT BEINGABLETOSEEORSMELLTHEFOOD.OWADAYS ATTENTIONISGIVENTOINDIVIDUALCREW MEMBERPREFERENCEWITHREGARDTOPALATABILITYANDNUTRITIONALADEQUACYOFFOODITEMS DURINGMISSIONS -EDICALANDPSYCHOLOGICALPERSONNELHAVEALSOANOPPORTUNITYTOREVIEWALLDESIGN CONSIDERATIONSEARLYINTHEDESIGNPROCESSTOENSURETHATSPACECRAFTDESIGNANDSUPPORT SYSTEMSMEETMEDICALANDPSYCHOLOGICALREQUIREMENTS

&UNDAMENTALSOF3PACE-EDICINE



Table 1.3. The Space Shuttle Menu Currently Features More Than 70 Food Items and 20 Beverages. Shuttle Crewmembers Have a Varied Menu Every Day for 6 Days. Each Day, Three Meals Are Allowed, with a Repeat of Menus After 6 Days. The Pantry Also Provides Plenty of Foods for Snacks and in Between Meal Beverages and for Individual Menu Change. Thermostabilized s (EATPROCESSEDFOODShOFF THE SHELFvITEMS INALUMINUMORBIMETALLICTINSANDRETORT POUCHES Irradiated s &OODSPRESERVEDBYEXPOSURETOIONIZINGRADIATION s 0ACKEDINmEXIBLEFOILLAMINATEDPOUCHES Intermediate Moisture s $RIEDFOODSWITHLOWMOISTURECONTENTSUCHASDRIEDAPRICOTS s 0ACKEDINmEXIBLEPOUCHES Freeze Dried s &OODSPREPAREDTOTHEREADY TO EATSTAGE FROZENANDTHENDRIEDINAFREEZEDRYERTHAT REMOVESTHEWATERBYSUBLIMATION s &REEZE DRIEDFOODSSUCHASFRUITSMAYBEEATENASISWHILEOTHERSREQUIRETHEADDITIONOF HOTORCOLDWATERBEFORECONSUMPTION Re-hydratable s $RIEDFOODSANDCEREALSRE HYDRATEDWITHWATERPRODUCEDBYTHESHUTTLEORBITERSFUELCELL SYSTEM s 0ACKEDINSEMI RIGIDPLASTICCONTAINERWITHSEPTUMFORWATERINJECTION Natural Form s &OODSSUCHASNUTS CRUNCHBARS ANDCOOKIES s 0ACKEDINmEXIBLEPLASTICPOUCHES Beverages s $RYBEVERAGEPOWDERMIXES s 0ACKEDINRE HYDRATABLECONTAINERS



(UMAN-ARSMISSION

4HEEVENTUALDECISIONTOGOTO-ARSWILLBESTRONGLYINʅUENCEDBYNON SCIENTIʄCREA SONS3CIENCE THOUGHAFACTOR WILLNOTBETHEDRIVER4HUS THEREALISSUEHEREIS IF HUMANS ARE TO GO TO ANY PLANETARY BODY WHAT SCIENCE AND RELATED ACTIVITIES CAN BE PERFORMEDTOTAKEMAXIMUMADVANTAGEOFTHEPRESENCEOFHUMANSONTHESEMISSIONS &ORMANY THEMAJORSCIENCEOBJECTIVEOFSENDINGHUMANSTO-ARSISTOSEARCHFOR EVIDENCE OF PAST OR CURRENT LIFE ON ANOTHER PLANET INVESTIGATE THE -ARTIAN CLIMATE STUDY-ARTIANGEOLOGYANDGEOPHYSICS ANDPREPAREFORFUTUREMISSIONSANDSUSTAINED HABITATION!HUMAN-ARSMISSIONCANALSOBEREGARDEDASANIMPORTANTCULTURALTASK FOR HUMANKIND WITH THE OBJECTIVE TO GLOBALIZE THE VIEW OF OUR HOME PLANET %ARTH THEREBYCONTRIBUTINGTOTHESOLUTIONOFLOCALCONʅICTS)NANYCASE AHUMAN-ARSMIS SIONWOULDMEETTHENATURALHUMANNEEDTOEXPLOREANDEXPANDTONEWREGIONS

)NTRODUCTIONTO3PACE,IFE3CIENCES



5SINGTHECURRENTROCKETTECHNOLOGY TRAVELINGBETWEEN%ARTHAND-ARSWILLREQUIRE LOTSOFFUELANDGOODTIMING4HEMOSTFUEL EFʄCIENTTRAJECTORYOCCURSWHEN%ARTHISAT AOȀCLOCKPOSITIONATLAUNCHAND-ARSISATABOUTOȀCLOCKǻAJUXTAPOSITIONTHAT OCCURSJUSTONCEEVERYMONTHS4HEʄRSTLEGWILLTAKEABOUTMONTHS!STRONAUTS MUSTWAITON-ARSFORTHEIRLAUNCHTOWARDHOMEUNTIL%ARTHISINALIGNMENT!FTER THEIRSURFACESTAYOFAPPROXIMATELYDAYS THEASTRONAUTSWILLASCENDTOORBIT REN DEZVOUSWITHTHETRANSITHABITAT ANDRETURNTO%ARTH4OTALMISSIONDURATIONWILLBE ABOUTMONTHS&IGURE  )N .!3!EMBARKEDONTHENEW6ISIONFOR3PACE%XPLORATION4HISWASAN AMBITIOUSPLANTOSENDHUMANMISSIONSTOTHE-OON -ARS ANDBEYONDASPARTOFTHE #ONSTELLATIONPROGRAM%ARLYIN FOLLOWINGTHERECOMMENDATIONSPROVIDEDBY THE!UGUSTINE#OMMISSION;!UGUSTINEETAL = 530RESIDENT"ARRACK/BAMA ANNOUNCED THE CANCELATION OF THIS PROGRAM )NSTEAD HE CALLED FOR A SHIFT IN FOCUS DIRECTING.!3!ȀSATTENTIONTOWARDSSENDINGHUMANSDIRECTLYTO-ARSUSINGINTERNA TIONALCOOPERATION ASWELLASINNOVATIVEANDCOST EFFECTIVENEWTECHNOLOGIES 4HE DESIGN DECISIONS AND PLANS OUTLINED WITHIN THE .!3! $ESIGN 2EFERENCE !RCHITECTURE;.!3!$2!=ARELIKELYTOREPRESENTARELEVANTBASELINEFORANY FUTURE-ARSMISSION4HISREFERENCEMISSIONISASSUMEDTOBEGINWITHCARGOLAUNCHES INTHELAUNCHWINDOWANDTHECREWLAUNCHINGINTHEWINDOW0RECURSOR MISSIONS TO -ARTIAN ORBIT AS PLEDGED BY 53 0RESIDENT /BAMA IN AN !PRIL  SPEECHATTHE.!3!+ENNEDY3PACE#ENTER SHOULDOCCURBY 4HE REFERENCE MISSION CONSISTS OF TWO CARGO SPACECRAFT 4HE ʄRST WILL PLACE THE ASCENTSTAGEANDCARGOONTHESURFACEOF-ARS4HESECONDWILLPLACETHESURFACEHABITAT IN-ARTIANORBIT4HEASCENTSTAGEWILLLANDWITHAN)N3ITU2ESOURCE5TILIZATION)325 UNIT THAT WILL PRODUCE OXYGEN FROM THE -ARTIAN ATMOSPHERE ALONG WITH METHANE BROUGHTFROM%ARTHTOFUELTHEASCENTSTAGE!CREWOFSIXWILLBELAUNCHEDYEARSLATER

Figure 1.19. Top: Schematic of the Orbits of Earth and Mars Showing Their Position for a More Fuel-Efficient Trajectory During Launch. Bottom: The Respective Positions of Earth and Mars Determine the Duration of Travel and Stay on the Martian Surface.



&UNDAMENTALSOF3PACE-EDICINE

4HECREWWILLBEMIXEDGENDERANDINTERNATIONALWITHTHEIRROLESBEINGPILOT PHYSICIAN GEOLOGIST BIOLOGIST ANDMECHANICALANDELECTRICALENGINEERS5PONARRIVALTHEYWILL RENDEZVOUSINORBITWITHTHEHABITATANDUSEITTOLANDON-ARS4HETRANSITMODULEWILL REMAININORBITFORTHEDURATIONOFTHESURFACEMISSION 5PONLANDING THEASTRONAUTSWILLTAKESEVERALWEEKSTOADAPT DURINGWHICHTHEYCAN SOMEWHATRECOVERFROMTHEIRMICROGRAVITYTRANSITANDCONDUCTONLYESSENTIALACTIVITIES !FTERTHISPERIOD THEYCANENGAGEINSCIENTIʄCRESEARCH!VARIETYOFROBOTIC PRESSUR IZED ANDUNPRESSURIZEDROVERS ASWELLASSCIENTIʄCEQUIPMENTANDDRILLSDELIVEREDBY THELANDERS WILLBEWAITINGFORTHECREW)TISASSUMEDTHATTHELANDINGWILLTAKEPLACE INANAREABELIEVEDTOBERELATIVELYSAFE BUTWHICHWILLPRESUMABLYNOTBEOFSUBSTANTIAL SCIENTIʄCINTEREST&ROMTHERETHEASTRONAUTSWILLUSEROVERSTOTRAVELDISTANCESOFUPTO HUNDREDS OF KILOMETERS TO ROUGHER MORE INTERESTING SITES 4HE ROBOTIC ROVERS ARE INTENDEDFORUSEINAREASDEEMEDTOBEPARTICULARLYLIKELYTOCONTAINLIFEOREVIDENCEOF PASTLIFE4HESEAREASMUSTBEPROTECTEDFROMCONTAMINATIONATALLCOSTSTOMAINTAINTHE INTEGRITYOFASTROBIOLOGICALINVESTIGATIONS4HEROVERSWILLBETELEOPERATEDTOINVESTIGATE THESESENSITIVEAREASWITHOUTCOMPROMISINGPLANETARYPROTECTIONPROTOCOLS $EVELOPINGTHETECHNICALCAPABILITYTOREACH-ARSISONLYONEASPECTOFTHENECES SARY PREPARATIONS IT IS EQUALLY IMPORTANT TO CONSIDER THE HUMAN FACTORS THAT WOULD AFFECTSUCHAMISSION(OWWILLTHEHUMANBODYANDMINDREACTTOEXTREMECIRCUM STANCESSUCHASMICROGRAVITY RADIATION ANDISOLATION(OWDOESANASTRONAUTPERFORM HISORHERWORKIFDIRECTCOMMUNICATIONTO%ARTHISNOTPOSSIBLE(OWCANALIFESUP PORTSYSTEMKEEPTHEASTRONAUTSALIVEANDHEALTHYDURINGAMULTI YEARMISSIONWITHOUT POSSIBILITY OF RE SUPPLY -ORE STUDIES AND EXPERIMENTS MUST BE PERFORMED TO GAIN KNOWLEDGE ON THESE AND NUMEROUS OTHER TOPICS TO ADEQUATELY PREPARE FOR A HUMAN MISSIONTO-ARS;3METETAL = ,UCKILY THE-ARSGRAVITYOFGMIGHTACTASACOUNTERMEASURETOTHEPHYSIOLOG ICALDECONDITIONINGTHATWILLTAKEPLACEINMICROGRAVITYDURINGTHETRIPFROM%ARTHTO -ARS(OWEVER LANDINGMANEUVERSON-ARSAND%ARTHARECHARACTERIZEDBYMAXIMUM G LOADSOFUPTOGDUETOATMOSPHERICDRAG)FTHEINTERPLANETARYCRUISEISCARRIEDOUT ATZEROGRAVITYLEVELIE IFNOARTIʄCIALGRAVITYISPROVIDEDWITHINTHESPACECRAFT SUCH HIGHGLEVELSINDECONDITIONEDASTRONAUTSAPPEARCRITICALFORTHEHEALTHOFTHECREW !NYTRIPBEYONDLOW%ARTHORBITWILLINVOLVERADIATIONTHREATSNOTFACEDBYRESI DENTS OF THE )33 WHICH SITS INSIDE THE PLANETȀS MAGNETIC ʄELD !  MONTH TRIP TO -ARS INCLUDINGǻMONTHSOFTRAVELTIMEEACHWAY WOULDEXPOSEANASTRONAUTTO NEARLYTHELIFETIMELIMITOFRADIATIONALLOWEDUNDER.!3!GUIDELINES4HEREARETWO PRIMARYFORMSOFHAZARDOUSSPACERADIATIONPARTICLESHIGH ENERGYPARTICLESEMITTED BYTHE3UNDURINGINTENSEʅARESANDMOREENERGETICCOSMICRAYSFROMUNDETERMINED GALACTICSOURCES3OLARANDGALACTICRADIATIONCANCAUSESEVERECELLULARDAMAGEOREVEN CANCERSEE#HAPTER 3ECTION 4HE-ARTIANATMOSPHERE ABOUTASDENSEAS %ARTHȀS MANAGESTOSTOPJUSTABOUTALLOFTHESOLARPARTICLES BUTITLETSMOSTOFTHE COSMICRAYSTHROUGH(OWEVER THECREWNEEDSTOBEPROTECTEDAGAINSTTHEOCCASIONAL SOLARʅAREWITHAȃSTORMSHELTER ȄEG WITHFOODRACKSANDWATERTANKSPACKEDAROUND THEWALLSTOABSORBTHERADIATION #OSMIC RAYS ARE A DIFFERENT STORY 4HEY ARE CONSTANTLY PRESENT COMING FROM ALL DIRECTIONS4HERADIATIONCONSISTSOFHEAVY SLOW MOVINGATOMICNUCLEITHATCANDOFAR MOREDAMAGETOMORECELLSTHANTHEALPHAANDBETAPARTICLESOFSOLARʅARES4HISRADIA TIONREQUIRESSEVERALMETERSOFSHIELDINGFORCOMPLETEBLOCKAGE ANDSINCETHENUCLEI

)NTRODUCTIONTO3PACE,IFE3CIENCES



COMEFROMALLDIRECTIONSATALLTIMES UNLIKETHEBRIEFSOLARʅARESTHATLASTONLYAFEW HOURSORDAYS ASTORMSHELTERWOULDBEINSUFʄCIENTTOPROTECTTHECREW4HEPLANET ITSELFOFFERSNATURALPROTECTIONAGAINSTCOSMICRAYSBYBLOCKINGHALFTHESKY)NADDI TION THEHABITATSOFTHE-ARSBASECANBECOVEREDWITHTHICKLAYERSOFSOILTOPROVIDE FULL TIMERADIATIONPROTECTION SONEARLYALLTHECREWȀSRADIATIONEXPOSUREWOULDOCCUR DURINGTHEPERIODOFINTERPLANETARYTRAVEL%VENIFSUCHSHIELDINGMETHODSPROVEDIF ʄCULTTOENGINEERS SOMESCIENTISTSBELIEVETHATTHECOSMICRAYDOSESCANSIMPLYBE ENDURED%XPOSURETOATHIN CONTINUOUSSTREAMOFRADIATIONDOESFARLESSDAMAGETHAN AN EQUAL MAGNITUDE OF RADIATION DELIVERED IN  DAY 4HERE IS STILL THE POSSIBILITY OF CANCER BUTTHISPROBABILITYISRATHERLOW 4HE COMBINED SOLAR AND COSMIC RAY PARTICLE EXPOSURE IS MEASURED IN 3IEVERTS 3VREM !NASTRONAUTONA TO MONTHJOURNEYTO-ARSWOULDBEEXPOSED TOABOUT3V OR3VONAROUND TRIP!NOTHERǻMONTHSONTHESURFACEWOULD BRINGANOTHER3V FORATOTALEXPOSUREOF3V,IMITSSETBY.!3!VARYWITHAGE ANDGENDERBUTRANGEFROMTO3V4HISDOSEWOULDLEADTOAINCREASEINTHE PROBABILITYOFCONTRACTINGAFATALCANCERLATERINLIFE COMPAREDTOANALREADYEXISTING CANCERRISKFORNON SMOKERSON%ARTH ANDWOULDPROBABLYBEACCEPTABLETOTHE VOLUNTEERSFORTHISMISSION(OWEVER SINCETHEBIOLOGICALEFFECTSOFCOSMICRADIATION AREPOORLYUNDERSTOOD THERESULTINGCANCERRISKMAYCONCEIVABLYBEOFFBYASMUCHAS AFACTOROF ANDTHUSJUMPTO ORDROPTO .OT MUCH RESEARCH CAN BE DONE SAFELY ON %ARTH TO INVESTIGATE THESE RADIATION EFFECTS ASCOSMICRAYSAREDIFʄCULTTOGENERATE ANDNOONEWOULDCONSENTTOBEING EXPOSEDTOATHEORETICALLYFATALDOSAGE4HE)33COULDPROVIDEAGOODTESTINGGROUND BECAUSELARGENUMBERSOFASTRONAUTSWILLBEEXPOSEDTOMODESTAMOUNTSOFRADIATION INTHEIR MONTHTOURSOFDUTY BUTAFULLINVESTIGATIONMIGHTREQUIREWAITINGDECADES UNTILTHESEASTRONAUTSRETIREANDDIEEITHEROFNATURALCAUSESOROFCANCER/BVIOUSLY -ARSMISSIONADVOCATESHAVENOINTENTIONOFWAITINGTHATLONG)TACTUALLYMAKESTHE MOSTSENSETOACCEPTTHERADIATIONRISKONTHE-ARSMISSION!FTERALL THISISAJOURNEY INTO THE UNKNOWN AND THE RISK OF RADIATION IS MILD COMPARED TO THE DANGERS THAT EXPLORERSON%ARTHHAVEFACED ANDOVERCOME INTHEPAST;2EIFSNYDER = 

#OUNTERMEASURES

7EWILLSEEINTHEFOLLOWINGCHAPTERSTHATTHECHANGESINHUMANPHYSIOLOGYDURING SPACEʅIGHT ARE APPROPRIATE ADAPTATIONS TO THE SPACE ENVIRONMENT 4HEY ARE NOT LIFE THREATENINGFORATLEASTMONTHS WHICHISTHELONGESTCONTINUOUSPERIODTHATHUMANS HAVESPENTINSPACE4HATȀSTHEGOODNEWS4HEBADNEWSISTHATADAPTATIONTOSPACE CREATESPROBLEMSUPONRETURNINGTO%ARTH$IFʄCULTYINSTANDING DIZZINESS ANDMUS CLE WEAKNESS POSE PROBLEMS AFTER LANDING 4HEREFORE APPROPRIATE COUNTERMEASURES MUSTBEDEVELOPEDTHATBALANCEHEALTHRISKAGAINSTMISSIONCONSTRAINTS ANDPARTICU LARLYTHELIMITEDRESOURCESREGARDINGMEDICALCAREPOSSIBILITIES #OUNTERMEASURESREFERTOTHEAPPLICATIONOFPROCEDURESORTHERAPEUTICPHYSICAL CHEMICAL BIOLOGICAL OR PSYCHOLOGICAL MEANS TO MAINTAIN HEALTH REDUCE RISK AND IMPROVETHESAFETYOFHUMANSPACEʅIGHT4HECOUNTERMEASURESTYPICALLYAIMAT A %LIMINATINGORPREVENTINGADVERSEANDHARMFULEFFECTSONCREWHEALTH%XAMPLES INCLUDETHEPROVISIONOFASUBSTITUTEGRAVITATIONALEFFECTINORBITARTIʄCIALGRAVITY THUSPREVENTINGMICROGRAVITYFROMDEGRADINGTHEHEALTHOFTHEASTRONAUTS



&UNDAMENTALSOF3PACE-EDICINE

B -ITIGATINGTHEEFFECTOFADVERSEORHARMFULAGENTSORENHANCINGTHEASTRONAUTȀS ABILITYTOWARDOFFTHEEFFECTSOFTHESEAGENTS%XAMPLESINCLUDEPREʅIGHTANDIN ʅIGHTEXERCISETOCOUNTERACTTHEEFFECTSOFMICROGRAVITY IN ʅIGHTADMINISTRATION OFMEDICATIONSTOPREVENTSPACEMOTIONSICKNESS ANDSPACECRAFTDESIGNCHANGES TOMINIMIZERADIATIONEXPOSURE C -INIMIZINGTHEEFFECTOFADVERSEORHARMFULAGENTSONTHECREWONCEMAL ADAPTA TION DISEASE OR INJURY HAS BEEN IDENTIʄED %XAMPLES INCLUDE ʅUID LOADING TO MINIMIZEPOSTʅIGHTORTHOSTATICINTOLERANCE&IGURE ORAPOSTʅIGHTREHABILI TATIONPROGRAMTOREVERSESPACEMISSION INDUCEDMUSCULO SKELETALORCARDIO VAS CULARDECONDITIONING 0REʅIGHTCOUNTERMEASURESINCLUDEACTIVITIESTOSUPPORTAPPROPRIATECREWSELECTION AND PSYCHOLOGICAL TRAINING ʄTNESS AND EXERCISE PHYSIOLOGICAL ADAPTIVE TRAINING A HEALTHSTABILIZATIONPROGRAM ANDCIRCADIANSHIFTING )N ʅIGHT COUNTERMEASURES INCLUDE THOSE ACTIVITIES NECESSARY TO MAINTAIN PHYSIO LOGICBALANCEANDHEALTH MENTALANDBEHAVIORALHEALTH NUTRITIONALHEALTH ANDPHYSI CAL ʄTNESS AND MISSION PERFORMANCE 4YPICAL PHYSICAL EXERCISE INCLUDES CYCLING RUNNINGONATREADMILL ORROWING 0OSTʅIGHT COUNTERMEASURES INCLUDE THOSE ACTIVITIES NECESSARY TO ASSIST THE CREW MEMBERSINARETURNTOPREʅIGHTPHYSICAL PHYSIOLOGICAL ANDBEHAVIORALHEALTHBASE LINES%XAMPLESOFCOUNTERMEASURESINCLUDE BUTARENOTLIMITEDTO CIRCADIANRHYTHM SHIFTING HORMONEREPLACEMENT ANDPHYSICALEXERCISE

Figure 1.20. A Shuttle Crewmember Prepares Containers of Drinking Water and Salt Tablets To Be Consumed by His Crewmates Prior to Re-entry.&LUID,OADING)S A 3TANDARD 0ROCEDURE ON !LL 3HUTTLE &LIGHTS AS AN %FFECTIVE #OUNTERMEASURE TO /RTHOSTATIC)NTOLERANCEUPON2ETURNTO%ARTHS'RAVITY#REDIT.!3! 

)NTRODUCTIONTO3PACE,IFE3CIENCES



Figure 1.21. French Cosmonaut Jean-Pierre Hai-gneré Is Hand Carried by Bround Personnel After Returning from a 6-Month Stay on Board the Russian Space Station Mir.#REDIT#.%3 

&OR LONG DURATION MISSIONS THE -IR AND )33 EXPERIENCE INDICATES THAT CURRENT IN ʅIGHTCOUNTERMEASURESARENOTOPTIMAL TOSAYTHELEAST%VIDENCEFORTHISISPRO VIDEDBYTHEIMAGESOFTHECOSMONAUTSUNABLETOSTANDIMMEDIATELYAFTERRETURNINGTO %ARTHAFTERALONG DURATIONSTAYONBOARD-IR4HEYAREHELPEDFROMTHESPACECRAFTAND ȃCEREMONIOUSLYHAULEDAROUNDLIKENABOBSINSEDANCHAIRSȄ&IGURE 4HESITUA TIONWITHTHE)33HASNOTCHANGEDMUCH!STRONAUTSONBOARDTHE)33EXERCISEONA CYCLE ERGOMETER ATREADMILL ORARESISTIVEEXERCISEDEVICEFORUPTOHDAY9ET CON SIDERABLEMUSCLEANDBONELOSSISOBSERVEDAFTERLANDINGSEE#HAPTER 3ECTION  #ONSEQUENTLY ITISLARGELYADMITTEDTHATUSINGTHECURRENTCOUNTERMEASUREMETHODS HUMANSWOULDNOTBEOPERATIONALAFTERLANDINGON-ARS 

!RTIʄCIALGRAVITY

/NEPOSSIBLECOUNTERMEASURETOTHEEFFECTSOFWEIGHTLESSNESSISTHEUSEOFARTIʄCIALLY PRODUCED GRAVITY ON BOARD THE SPACECRAFT !RTIʄCIAL GRAVITY COULD BE ACCOMPLISHED EITHERTHROUGHROTATIONOFTHEENTIREVEHICLEORBYTHEINCLUSIONOFANONBOARDCENTRI FUGE&ORAMORECOMPLETEDESCRIPTIONOFTHERATIONALEFORARTIʄCIALGRAVITY THEPOSSI BLESPACECRAFTDESIGNOPTIONS ANDITSPOTENTIALEFFECTONASPACECREW THEREADERIS REFERREDTOTHEBOOK!RTIʄCIAL'RAVITYBY#L¦MENTAND"UKLEY; 3PRINGER= 4HERATIONALEFORUSINGCENTRIFUGATIONISTHATDURINGROTATIONABOUTANECCENTRICAXIS THE RESULTING CENTRIFUGAL FORCE PROVIDES AN APPARENT GRAVITY VECTOR 4HE CENTRIFUGAL FORCEPRODUCEDBYROTATIONISDEPENDENTUPONTWOPARAMETERSOFTHEROTATINGSTRUCTURE



&UNDAMENTALSOF3PACE-EDICINE

Figure 1.22. These Drawings Illustrate the Difference Between the Physical Effects of Centrifugation on Earth (Left) and in Space (Right). /N %ARTH THE 'RAVITO )NERTIAL&ORCE')& )S4ILTED2ELATIVETOTHE0LANEOF2OTATION)N3PACE !RTIlCIAL 'RAVITY !' )S !LIGNED WITH THE 0LANE OF 2OTATION !LSO 3HOWN )S THE 'RAVITY 'RADIENTIN"OTH#ONDITIONS&OR%XAMPLE INTHE2IGHT&IGURE THE!',EVEL)SG ATTHE&EETANDGATTHE(EADFORA2OTATION2ATEOFRPM!DAPTEDFROM #L£MENTAND"UKLEY;]).

THE SQUARE OF ITS ANGULAR RATE Z AND ITS RADIUS R /N %ARTH THE CENTRIFUGAL FORCE COMBINESWITHTHEGRAVITATIONALFORCE ANDTHERESULTINGVECTOR THESO CALLEDGRAVITO INERTIALFORCE ISBOTHLARGERINMAGNITUDETHANTHECENTRIFUGALFORCEITSELFANDTILTED WITHRESPECTTOGRAVITY)NMICROGRAVITY THESUBJECTWILLONLYBEEXPOSEDTOACENTRIFU GALFORCE REFERREDTOASARTIʄCIALGRAVITY&IGURE  "ECAUSETHECENTRIFUGALFORCEDEPENDSONBOTHROTATIONALRATEANDRADIUS ASPECIʄC INCREASEINTHEARTIʄCIALGRAVITYLEVELCANBEACHIEVEDEITHERBYINCREASINGTHERADIUS ORBYINCREASINGANGULARRATE4HISTRANSLATESTOATRADE OFFBETWEENCOSTANDCOM PLEXITY WHICHDEPENDSMOSTLYONTHERADIUSOFTHESTRUCTUREVERSUSTHEPHYSIOLOGICAL AND PSYCHOLOGICAL CONCERNS BOTH OF WHICH DEPEND MOSTLY ON ITS ANGULAR RATE ;$IAMANDIS = /NE SIGNIʄCANT DRAWBACK OF A ROTATING ENVIRONMENT IS THE #ORIOLIS FORCE THAT IS GENERATEDEVERYTIMEALINEARMOTIONISATTEMPTEDINANYPLANENOTPARALLELTOTHEAXIS OFROTATION4HE#ORIOLISFORCEHASAMAGNITUDEOFw6WHEREwISTHEROTATIONRATE FORTHEROTATINGENVIRONMENTAND6ISTHELINEARVELOCITYOFTHEMOVINGOBJECT7HEN ATTEMPTINGANYLINEARMOVEMENTOUTOFTHEPLANEOFROTATION THE#ORIOLISFORCECOM BINESWITHTHECENTRIFUGALFORCETOPRODUCEADIFFERENTAPPARENTGRAVITYVECTORINMAG NITUDEALONEORINBOTHMAGNITUDEANDDIRECTION4OAHUMANINAROTATINGENVIRONMENT THISVECTORMAYBEMANIFESTINTWOWAYS&IRST ITADDSTOTHEAPPARENTWEIGHTOFABODY MOVINGINTHEDIRECTIONOFROTATIONANDSUBTRACTSFROMTHEAPPARENTWEIGHTWHENMOV INGAGAINSTTHEDIRECTIONOFMOTION3ECOND WHENABODYMOVESTOWARDTHECENTEROF ROTATION THE#ORIOLISFORCEISEXERTEDINTHEDIRECTIONOFROTATIONATRIGHTANGLESTOTHE BODYȀSMOTIONWHENMOVINGAWAYFROMTHECENTEROFROTATIONTHEFORCEISOPPOSITETO THE DIRECTION OF ROTATION "Y CONTRAST A MOTION PARALLEL TO THE AXIS OF ROTATION WILL GENERATENO#ORIOLISFORCE;3TONE = 4HE#ORIOLISFORCESAFFECTNOTONLYWHOLE BODYMOVEMENTSBUTALSOTHEVESTIBULAR SYSTEMSEE#HAPTER 3ECTION 2OTATIONOFTHEHEADOUTOFTHEPLANEOFROTATION GENERATES CROSS COUPLED ANGULAR ACCELERATIONS THAT INDUCE STIMULATION OF ALL THREE SEMICIRCULAR CANALS 3UCH HEAD MOVEMENTS IN A STATIONARY ENVIRONMENT DO NOT

)NTRODUCTIONTO3PACE,IFE3CIENCES



N ORMALLYSTIMULATESOMEOFTHECANALS ANDTHISRESULTSINILLUSORYSENSATIONSOFBODILY ORENVIRONMENTALMOTION.AUSEAANDVOMITINGMAYRESULTAFTERAFEWHEADMOVE MENTS PARTICULARLYIFTHEANGULARVELOCITYOFTHECENTRIFUGEISHIGH"ASEDONGROUND BASEDSTUDIESPERFORMEDINTHESUSINGSLOWROTATINGROOMS ITWASPOSTULATEDTHAT THELIGHTESTACCEPTABLESYSTEMFORPROVIDINGȃCOMFORTABLEȄARTIʄCIALGRAVITYUSINGA ROTATING SPACECRAFT WOULD BE ONE HAVING A RADIUS OF ROTATION NOT LOWER THAN  M ROTATINGATRPM ANDPROVIDINGAGRAVITYLEVELRANGINGFROMTOG;4HOMPSON  (ALL = -ORE RECENT STUDIES SHOWED THAT THE SUBJECTS IN A ROTATING ENVIRONMENTCOULDTOLERATEAROTATIONRATEUPTORPM PROVIDEDTHATTHEEXPOSUREIS PROGRESSIVE;,ACKNERAND$I:IO = OREVENUPTORPMAFTERHABITUATIONOFTHE MOTIONSICKNESSSYMPTOMS;9OUNGETAL = 4HEȃPRESCRIPTIONȄOFHOWMUCHACCELERATIONGRAVITYOVERWHATPERIODOFTIMEAND INWHATDIRECTIONISREQUIREDFORMAINTAININGNORMALHEALTHISCURRENTLYUNKNOWNAND LOGISTICALLYVERYDIFʄCULTTODETERMINE!ROTATINGSPACECRAFTTHATPROVIDESACONSTANT  G ACCELERATION WOULD BE IDEAL (OWEVER A MANEUVERING STATION PRESENTS SERIOUS DESIGN ʄNANCIAL AND OPERATIONAL CHALLENGES !LSO HEAD MOVEMENTS AND RESULTANT #ORIOLISANDCROSS COUPLEDACCELERATIONSONAROTATINGSPACECRAFTMAYLIMITTHEUSEFUL NESSOFCENTRIFUGATIONFOROTHERTHANBRIEFPERIODSOFINTERMITTENTSTIMULATION&ROMA PRACTICAL PERSPECTIVE IT IS VERY LIKELY THAT HUMANS DO NOT NEED GRAVITY OR FRACTION OFIT HADAYTOREMAINHEALTHY)FINTERMITTENTGRAVITYISSUFʄCIENT WEWONȀTNEED A PERMANENTLY ROTATING SPACECRAFT TO PRODUCE A CONSTANT GRAVITY FORCE !N ONBOARD DEVICESUCHASAHUMANRATEDSHORT RADIUSCENTRIFUGE PRESENTSAREALISTICNEAR TERM OPPORTUNITYFORPROVIDINGTHISARTIʄCIALGRAVITY 3EVERALDESIGNSFORANONBOARDSHORT RADIUSCENTRIFUGEHAVEBEENPROPOSED)WAS THE0RINCIPAL)NVESTIGATOROFANEXPERIMENTUSINGAHUMAN RATEDCENTRIFUGEGENERATING ORGALONGTHELONGITUDINALBODYAXIS WHICHʅEWABOARDTHE.EUROLABMISSION OFTHESPACESHUTTLE343  IN&IGURE 4HISEXPERIMENTWASANDREMAINS THE ʄRST IN ʅIGHT EVALUATION OF ARTIʄCIAL GRAVITY ON ASTRONAUTS 4HE RESULTS OF THIS EXPERIMENT DESCRIBEDINMOREDETAILIN#HAPTER SUGGESTEDTHATCENTRIFUGALFORCEOF  G WAS WELL TOLERATED BY THE CREW AND THAT CARDIO VASCULAR DECONDITIONING WAS REDUCEDINTHOSEASTRONAUTSWHORODETHECENTRIFUGEMINEVERYOTHERDAYDURINGA  DAYSPACEMISSION;#L¦MENTAND2ESCHKE = !NINTERESTINGNEWAPPROACHISAHUMAN POWEREDCENTRIFUGETHATCOUPLESEXERCISEWITH ARTIʄCIALGRAVITY;'REENLEAFETAL =%XERCISEASACOUNTERMEASUREWASINTRODUCEDIN THE DAYS OF THE 'EMINI PROGRAM )T HAS TAKEN ON VARIOUS INGENIOUS FORMS OF ELASTIC PNEUMATIC MECHANICAL HYDRAULIC ANDELECTRICALDEVICES4HESEDEVICESAPPLYAFORCE NOTANACCELERATION ANDTHEYONLYPARTIALLYPROTECTCREWMEMBERS&OREXAMPLE CREW MEMBERSWEARAHARNESSATTACHEDTOANEXERCISEBIKEORTREADMILLANDAREHELDȃDOWNȄ DURINGEXERCISE%LASTICDEVICESCANEFFECTIVELYCREATEFORCE BUTNOTSUSTAINEDACCELERATION $OINGSUCHACTIVITIESDURINGCENTRIFUGATIONWOULDBEMUCHMOREEFFECTIVE 6ARIOUSDESIGNSHAVEBEENPROPOSED SUCHASTHEȃ4WIN"IKEȄOFTHE5NIVERSITYOF 5DINE THEȃ3PACE#YCLEȄOFTHE5NIVERSITYOF#ALIFORNIAAT)RVINE&IGURE AND .!3! !MES 2ESEARCH #ENTERȀS HUMAN POWERED CENTRIFUGE ;#L¦MENT AND "UKLEY =)TISBELIEVEDTHATEXERCISINGUNDERTHESEINCREASEDINERTIALFORCESWILLDECREASE THEAMOUNTOFTIMEREQUIREDTOEXERCISEFORMAINTAININGHEALTHANDʄTNESSINSPACE )FTHERESULTSPROVEPOSITIVEANDTHEAMOUNTOFEXERCISEISREDUCEDBYCENTRIFUGATION

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Figure 1.23. This 0.65-m Radius Human-Rated Centrifuge Developed by ESA Flew on Board the Neurolab Mission (STS-90). 4HIS %XPERIMENT )NVESTIGATED THE !DAPTATION OF THE 6ESTIBULAR 3YSTEM IN !STRONAUTS BY $ETECTING #HANGES IN 0ERCEIVED-OTIONAND/RIENTATIONIN-ICROGRAVITY#REDIT.!3! 

Figure 1.24. From Left to Right Are Depicted the Twin Bike, the NASA Human-Powered Centrifuge, and the Gondola of the Space Cycle (the Cycle Itself Is Not Shown). !LL4HESE $EVICES #OMBINE 0HYSICAL %XERCISES AND 3USTAINED )NERTIAL &ORCES'ENERATEDBY#ENTRIFUGATION&OR-ORE$ETAILSON4HESE$EVICES 2EADERS !RE2EFERREDTOTHE"OOKArtificial GravityBY#L£MENTAND"UKLEY;].

THENSUCHDEVICESCOULDBEAGOODCANDIDATECOUNTERMEASUREFORTHE)33 THESPACE CRAFTENROUTETO-ARS ORTHE-ARTIANHABITAT 

!NEWSCIENCEISBORN

3PACELIFESCIENCESISAYOUNGSCIENCE HAVINGCOMEINTOEXISTENCEWITHTHEʄRSTSTUD IES CARRIED OUT ON ANIMALS DURING THE ʄRST SUBORBITAL ʅIGHT LESS THAN  YEARS AGO 3INCETHEN PEOPLEHAVEVISITEDTHE-OONANDHAVELIVEDINSPACEFORABOUTTHEPERIOD PLANNED FOR A MISSION TO -ARS 3TILL OUR UNDERSTANDING OF HOW SPACEʅIGHT AFFECTS LIVINGORGANISMSREMAINSRUDIMENTARY

)NTRODUCTIONTO3PACE,IFE3CIENCES



4HE)33 NOWFULLYOPERATIONALWITHAPERMANENTCREWOFSIX SHOULDPROVEANIDEAL PLATFORM FOR STUDYING FUNDAMENTAL BIOLOGICAL PROCESSES IN MICROGRAVITY 4HIS WILL UNDOUBTEDLY LEAD TO THE GROWTH AND DEVELOPMENT OF A NEW SCIENCE GRAVITATIONAL PHYSIOLOGY 'RAVITY AFFECTS SOME MATERIALS AND ʅUID DYNAMICS )T IS REQUIRED FOR CONVECTIVE MIXINGANDOTHERWEIGHT DRIVENPROCESSES SUCHASDRAININGOFWATERTHROUGHSOIL AND ASSURINGTHATWHATGOESUPCOMESDOWN/NEMIGHTPREDICTTHATPLANTSWOULDGROW TALLER WITHOUT GRAVITY YET THE LACK OF GRAVITY MIGHT FACILITATE INCREASED LEVELS OF GROWTH INHIBITORYORAGINGENVIRONMENTALFACTORSAROUNDTHEPLANTS THEREBYCAUSING THEMTODWARF'RAVITYALSOHASAROLETOPLAYINDEVELOPMENTOFLOAD BEARINGSTRUC TURES4HESCALINGEFFECTOFGRAVITYISWELLKNOWNTHEPERCENTAGEOFBODYMASSCON TRIBUTINGTOSTRUCTURALSUPPORTISPROPORTIONALTOTHESIZEOFALANDANIMALEG G MOUSE^  KG HUMAN^ AND   KG ELEPHANT^  4HIS SCALING EFFECTINLANDANIMALSWOULDLIKELYCHANGEINSPACEANDCOULDRESULTINASTATICSCALE COMPARABLETOMARINEMAMMALSON%ARTH^OFMASSASSUPPORTINGTISSUESOVERA WIDERANGEOFWEIGHTS ,EGSAREBOTHERSOMEINSPACEANDNOTONLYGETINTHEWAYBUT ALSOAREINVOLVEDINTHEʅUIDSHIFTSTHATOCCUREARLYIN ʅIGHT7HETHERLEGSWOULDDIS APPEAR OVER TIME WITHOUT GRAVITY PERHAPS SIMILAR TO THE EXTRA TERRESTRIAL %4 OR BECOMEMORELIKEGRASPINGTALONSISUNKNOWN&ORMFOLLOWSFUNCTION ANDASFUNCTION CHANGES SOWILLFORM(OWMUCHCHANGEANDWHATFORMORGANISMSWILLASSUMEOVER TIMEINSPACEISUNKNOWN;-OREY (OLTON = $ATATODATESUGGESTTHATCERTAINBIOLOGICALSTRUCTURESHAVEEVOLVEDTOSENSEAND OPPOSEBIOMECHANICALLOADS ANDTHOSESTRUCTURESOCCURATTHECELLULARLEVELASWELLAS ATTHEORGANISMLEVEL4HEREISEVIDENCETHATTHEMUSCULO SKELETALSYSTEMOFVERTE BRATESCHANGEFOLLOWINGACUTEEXPOSURETOSPACESEE#HAPTER 3ECTION 7HAT WILL HAPPEN OVER MULTIPLE GENERATIONS IS SPECULATIVE 4HE ȃFUNCTIONAL HYPOTHESISȄ THEORYSUGGESTSTHATWHATISNOTUSEDISLOST)FTHISTHEORYHOLDSOVERMULTIPLEGENERA TIONSINSPACE THENGRAVITY DEPENDENTSTRUCTURESMAYULTIMATELYDISAPPEARORASSUME AVERYDIFFERENTAPPEARANCEINSPACE4HENEXTCHAPTERREVEALSTHATWEONLYHAVESHORT SNAPSHOTSOFHOWSMALLLIVINGORGANISMSACTUALLYCHANGEINTHESPACEENVIRONMENT !NOTHEREXAMPLEISPLANTS0LANTSARETHEʄRSTORGANISMSTOBERAISEDTOTHEPOINTOF PRODUCINGSEEDSINSPACE FROMSEEDSTHATWERETHEMSELVESRAISEDINMICROGRAVITYSEE #HAPTER 3ECTION 7ENOWKNOWTHATPLANTSCANGROWINSPACE BUTTHE-IRAND )33STUDIESHAVEINDICATEDTHATAIRANDWATERREQUIRESPECIALMANAGEMENTINMICRO GRAVITY&URTHERSTUDIESINTHISAREAAREOFPARAMOUNTIMPORTANCEIFONEWANTSTOMOVE FROMTHECURRENTPHYSICAL CHEMICALTOECOLOGICALCLOSEDLIFESUPPORTSYSTEMS #ARRYING OUT RESEARCH IN SPACE OFTEN COMES AT A CONSIDERABLE COST SOMETIMES HUMAN ASDEMONSTRATEDBYTHE#OLUMBIATRAGICEVENT 4HEMOSTSTRIKINGDIFʄCULTIES ARETHESMALLSUBJECTPOOLAVAILABLE THELACKOFADEQUATECONTROLS ANDTHEFACTTHATSCI ENCE IS BY NECESSITY SECONDARY TO MISSION SAFETY WHEN CONDUCTING EXPERIMENTS IN SUCHAHOSTILEENVIRONMENT.EVERTHELESS THESUCCESSOFTHEMANNEDSPACEPROGRAMIS DEPENDENTONTHECONCOMITANTSUCCESSOFLIFESCIENCESRESEARCHINMICROGRAVITYTOSOLVE THECONSIDERABLEDANGERSSTILLFACEDBYCREWMEMBERSONLONG DURATIONMISSIONS )NTHISRESPECT THEHUMAN-ARSMISSIONREPRESENTSANOTHERFASCINATINGCHALLENGE FOR SPACE MEDICINE 3UCH A MISSION WHEN IT IS UNDERTAKEN WILL PROBABLY BE THE LONGESTPERIODOFEXPOSUREOFANYPERSONTOAREDUCEDGRAVITATIONALENVIRONMENT AND



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PROBABLYTHELONGESTPERIODAWAYFROM%ARTH TOO!RECENTREPORTALSOSUGGESTEDTHAT RADIATIONON-ARSMIGHTBEATMUCHHIGHERLEVELSTHANPREVIOUSLYBELIEVED3OHIGHIN FACT THATITWOULDMAKELIVINGTHEREALMOSTIMPOSSIBLE!LLTOGETHER THESECONDITIONS MAKEAHUMAN-ARSMISSIONACHALLENGEFROMBOTHTHEPHYSIOLOGICALANDPSYCHOLOGI CALPOINTSOFVIEW 4HE HISTORICAL RECORD OFFERS A RICH SET OF EXAMPLES OF EXPLORATION ǻ #HRISTOPHER #OLUMBUSINHISDISCOVERYOFTHE.EW7ORLD 6ASCODE'AMASAILINGDIRECTLYFROM 0ORTUGALTO)NDIA AND,EWIS#LARKINTHEʄRSTOVERLANDEXPEDITIONUNDERTAKENBYTHE 5NITED3TATESTOTHE0ACIʄC#OAST FOREXAMPLE4HESEEXPEDITIONSTOUNKNOWNTERRITO RIES AND BACK RANK AS SOME OF THE GREATEST VOYAGES OF DISCOVERY IN HUMAN HISTORY "ECAUSEOFTHESCIENTIʄCANDGEOGRAPHICALDISCOVERIESTHATWEREMADEATTHETIME THEY STANDINSIGNIʄCANCEALONGTHEPLANNEDHUMANEXPLORATIONOF-ARS4HEYAREMANY PARALLELSBETWEENTHESEJUMPSINTOTERRAINCOGNITAǻUNEXPLOREDLAND!LLTHESEHISTORI CALEXPEDITIONSTOOKTHENECESSARYEQUIPMENT COLLECTIVESKILLSET ANDVISIONTOGOINTO ANUNKNOWNWORLDINSEARCHOFMANYTHINGS4HEEXPEDITIONSREDEʄNED LITERALLY A QUESTFORSCIENTIʄCUNDERSTANDINGABOUT%ARTHANDSETTHEFOUNDATIONFORCOLONIZATION 4HESMALLNUMBEROFVESSELSANDTIMEFRAMEAREQUITESIMILARFORTHE-ARSMISSIONAND FORTHE6ASCODE'AMAAND,EWIS#LARKȀSEXPEDITIONS(OWEVER THECREWSIZEWAS MUCHLARGERANDMANYLIVESWERELOSTINTHEHISTORICALEXPEDITIONS&IGURE  4HEPUBLICISPRESUMABLYNOTREADYFORPAYINGSUCHAPRICEINHUMANLIVESFORTHE -ARSMISSION(ENCE MOREADVANCESINRESEARCHANDTECHNOLOGYARENEEDEDBEFORE THEHUMANEXPLORATIONOF-ARSCANBEACHIEVEDWITHMINIMALRISK4HEREISNODOUBT HOWEVER THATLIKETHEHISTORICALEXPEDITIONS THEEXPLORATIONOF-ARSWILLBEEXTREMELY INʅUENTIALINTERMSOFOURKNOWLEDGEOFTHEWORLDANDSATISFYTHEDESIREOFHUMANITY TOEXPLOREANDEXPAND

Figure 1.25. Historical Perspective for Human Exploration Missions.#OMPARISON"ETWEEN THE .!3! -ARS -ISSION ,EWIS AND #LARKS %XPEDITION !CROSS THE ,OUISIANA 4ERRITORY 6ASCODE'AMAS&IRST$IRECT3AILINGFROM%UROPETO)NDIA AND#HRISTOPHER #OLUMBUSS$ISCOVERYOF!MERICAIN4ERMSOF-ISSION$URATION .UMBEROF#REW AND6ESSELS

)NTRODUCTIONTO3PACE,IFE3CIENCES



2EFERENCES !UGUSTINE .2 !USTIN 7- #HYBA # ET AL  3EEKING A HUMAN SPACEʅIGHT PROGRAM WORTHY OF A GREAT NATION 2EVIEW OF 53 (UMAN 3PACEʅIGHT 0LANS #OMMITTEE7ASHINGTON $#53#ONGRESS "ARANY2 5NTERSUCHUNGEN¹BERDENVOM6ESTIBULARAPPARATDES/HRESREʅEKTO RISCH AUSGEL³STEN RHYTHMISCHEN .YSTAGMUS UND SEINE "EGLEITERSCHEINUNGEN -ONATSCHR/HRENKEILKDEǻ "ARRATT- !3PACE-EDICINE-ANIFESTO.OTESOFTHE,ECTUREON#URRENTAND &UTURE )SSUES IN 3PACE -EDICINE PRESENTED AT THE 3UMMER 3ESSION OF THE )NTERNATIONAL3PACE5NIVERSITY 3TOCKHOLM "ARRATT - 0OOL 3 EDS  0RINCIPLES OF #LINICAL -EDICINE FOR 3PACE &LIGHT .EW9ORK .93PRINGER #HURCHILL3% )NTRODUCTIONTOHUMANSPACELIFESCIENCES)N+EYSTO3PACE!N )NTERDISCIPLINARY!PPROACHTO3PACE3TUDIES(OUSTON! 2YCROFT-EDS "OSTON -!-C'RAW(ILL PPǻ #L¦MENT' "UKLEY! !RTIʄCIAL'RAVITY.EW9ORK .93PRINGER #L¦MENT ' 3LENZKA +  &UNDAMENTALS OF 3PACE "IOLOGY %L 3EGUNDO #! -ICROCOSM0RESS.EW9ORK .93PRINGER #L¦MENT' 2ESCHKE-& .EUROSCIENCEIN3PACE.EW9ORK .93PRINGER #OLLINS- -ISSIONTO-ARS.EW9ORK .9'ROVE7EIDENFELD $E(ART2,ED  &UNDAMENTALSOF!EROSPACE-EDICINE 0HILADELPHIA 0!,EA &EBIGER $IAMANDIS 0(  #OUNTERMEASURES AND ARTIʄCIAL GRAVITY )N &UNDAMENTALS OF 3PACE,IFE3CIENCES#HURCHILL3%ED -ALABAR &,+RIEGER0UBLISHING#OMPANY 6OLUME #HAPTER PPǻ %CKART 0  3PACEʅIGHT ,IFE 3UPPORT AND "IOSPHERICS $ORDRECHT +LUWER !CADEMIC0UBLISHERS 3PACE4ECHNOLOGY,IBRARY 'REENLEAF *% 'UNDO $0 7ATENPAUGH $% -ULENBURG '- ET AL  #YCLE POWEREDSHORTRADIUSM CENTRIFUGE%FFECTOFEXERCISEVERSUSPASSIVEACCEL ERATIONONHEARTRATEINHUMANS(OUSTON 48.ATIONAL!ERONAUTICSAND3PACE !DMINISTRATION .!3!4-  PPǻ (ALL47 !RTIʄCIALGRAVITY)N/UTOFTHIS7ORLDǻ4HE.EW&IELDOF3PACE !RCHITECTURE (OWE !3 3HERWOOD " EDS 2ESTON 6! !MERICAN )NSTITUTE OF !ERONAUTICS!STRONAUTICS #HAPTER PPǻ (ENRY*0 3YNOPSISOFTHE2ESULTSOFTHE-2 AND-! &LIGHTS)N2ESULTS OFTHE0ROJECT-ERCURY"ALLISTICAND/RBITAL#HIMPANZEE&LIGHTS (OUSTON 48 .ATIONAL!ERONAUTICS3PACE!DMINISTRATION .!3!30  #HAPTER ,ACKNER*2 $I:IO0 (UMANORIENTATIONANDMOVEMENTCONTROLINWEIGHTLESS NESSANDARTIʄCIALGRAVITYENVIRONMENTS%XPERIMENTAL"RAIN2ESEARCHǻ ,UJAN "& 7HITE 2*  (UMAN 0HYSIOLOGY IN 3PACE 4EACHERȀS -ANUAL ! #URRICULUM 3UPPLEMENT FOR 3ECONDARY 3CHOOLS (OUSTON 48 5NIVERSITIES 3PACE2ESEARCH!SSOCIATION -OREY (OLTON %2  'RAVITY A WEIGHTY TOPIC )N %VOLUTION ON 0LANET %ARTH 4HEIMPACTOFTHE0HYSICAL%NVIRONMENT2OTHSCHILD, ,ISTER!EDS .EW9ORK .9!CADEMIC0RESS



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.!3!  (UMAN %XPLORATION OF -ARS $ESIGN 2EFERENCE !RCHITECTURE  (OUSTON 48.!3! .EWTON) 0RINCIPIA #HAPTER6)) "OOK))) .ICOGOSSIAN!% 0ARKER*& 3PACE0HYSIOLOGYAND-EDICINE .!3!30  7ASHINGTON $# .ATIONAL !ERONAUTICS  3PACE !DMINISTRATION 3CIENTIʄC  4ECHNICAL)NFORMATION"RANCH 2EIFSNYDER2 2ADIATION(AZARDSONA-ARS-ISSION-)4-ARS3OCIETY9OUTH #HAPTER4HE-ARTIAN#HRONICLES;ONLINE=!VAILABLEHTTPCHAPTERSMARSSOCIETY ORGYOUTHMCISSUEINDEXPHP;!CCESSED/CTOBER= 2OGERS -*" 6OGT ', 7ARGO -*  4HE -ATHEMATICS OF -ICROGRAVITY 7ASHINGTON $# .ATIONAL !ERONAUTICS  3PACE !DMINISTRATION .!3! %DUCATIONAL"RIEF%"    (1 3CHERER( "RANDT5 #LARKE!( -ERBOLD5 0ARKER2 %UROPEANVESTIBULAR EXPERIMENTSONTHE3PACELAB MISSION#ALORICNYSTAGMUSINMICROGRAVITY %XPERIMENTAL"RAIN2ESEARCHǻ 3MET' .ORDHEIM4 (AMMONS% 2OSENBERG- !NALOG-APTO-ARS!PATH TOWARDS SUSTAINABLE HUMAN SPACE EXPLORATION 0APER PRESENTED AT THE )!# #ONFERENCE 0RAGUE 3EPTEMBER /CTOBER )!#  $ 3TONE27 !NOVERVIEWOFARTIʄCIALGRAVITY&IFTH3YMPOSIUMONTHE2OLEOFTHE 6ESTIBULARORGANSIN3PACE%XPLORATIONǻ!UGUST .AVAL!EROSPACE -EDICAL#ENTER 0ENSACOLA &, .!3!30  PPǻ 3TRINGLY,% #OUNTDOWNAND0ROCEDURESFOR0ROJECT-ERCURY!TLAS &LIGHT #HIMPANZEE 3UBJECT  &INAL 4ECHNICAL $OCUMENTARY 2EPORT (OLLOMAN !&" !EROMEDICAL2ESEARCH,ABORATORY4ECHNICAL$OCUMENTARY2EPOSITORYǻ 4HOMPSON!" 0HYSIOLOGICALDESIGNCRITERIAFORARTIʄCIALGRAVITYENVIRONMENTS INMANNEDSPACESYSTEMS&IRST3YMPOSIUMONTHE2OLEOFTHE6ESTIBULARORGANS INTHE%XPLORATIONOF3PACE ǻ*ANUARY 53.AVAL3CHOOLOF!VIATION -EDICINE 0ENSACOLA &, .!3!30  PPǻ 4HORNTON7% -OORE40 (EIGHTCHANGESINMICROGRAVITY)N2ESULTSOFTHE ,IFE 3CIENCES $3/S CONDUCTED ABOARD THE 3PACE 3HUTTLE ǻ 3PACE "IOMEDICAL 2ESEARCH )NSTITUTE (OUSTON 48 .!3! *OHNSON 3PACE #ENTER PPǻ 4ILLET "RISSON #ADET ,AVOISIER "OSSUT DE #ONDORCET $ESMAREST  2APPORT &AIT  LȀ!CAD¦MIE DES 3CIENCES SUR LA -ACHINE !¦ROSTATIQUE DE -RS $E -ONTGOLʄER 7ASSERSUG 2*  6ERTEBRATE BIOLOGY IN MICROGRAVITY !MERICAN 3CIENTIST ǻ 9OUNG,2 (ECHT( ,YNE,%ETAL !RTIʄCIALGRAVITY(EADMOVEMENTSDURING SHORT RADIUSCENTRIFUGATION!CTA!STRONAUTICAǻ

#HAPTER 3PACE"IOLOGY 'RAVITY PROVIDES A DIRECTIONAL STIMULUS THAT PLAYS AN IMPORTANT ROLE IN BASIC LIFE PROCESSESINTHECELL SUCHASBIOSYNTHESIS MEMBRANEEXCHANGE ANDCELLGROWTHAND DEVELOPMENT)TISLIKELYTHATTHEGROWTHANDDEVELOPMENTOFPLANTSAREDETERMINEDBY HORMONES WHOSETRANSPORTISALSOINʅUENCEDBYGRAVITY7ILLTHESEFUNCTIONSDEVELOP NORMALLYWHENDEPRIVEDOFTHEGRAVITATIONALSTIMULUS4HISCHAPTERWILLREVIEWTHE FUNDAMENTALQUESTIONSRAISEDINTHESPACEENVIRONMENTINTHEAREASOFGRAVITATIONAL BIOLOGY DEVELOPMENTALBIOLOGY PLANTBIOLOGY ANDRADIOBIOLOGY&ORMOREDETAILS THE READERS ARE REFERRED TO THE BOOK &UNDAMENTALS OF 3PACE "IOLOGY BY #L¦MENT AND 3LENZKA; 3PRINGER=&IGURE 

 7HATISLIFE )TISGENERALLYADMITTEDTHAT FORSCIENTIʄCPURPOSES ANOBJECTMUSTMEETSIXCRITERIATO BECONSIDEREDALIVE MOVEMENTEVENPLANTSMOVESTEMSSHOOTUPWARD ʅOWERS OPEN AND CLOSE AND LEAVES FOLLOW THE MOVEMENT OF THE 3UN   ORGANIZATION ANIMALSANDPLANTSHAVEORGANS WHOSESTRUCTUREISNEARLYIDENTICALWITHINTHESAME SPECIES  HOMEOSTASISTHEABILITYTOMAINTAINCONSTANTCONDITIONSWITHINTHEBODY   ENERGYALLLIVINGTHINGSABSORBANDUSEENERGY  REPRODUCTIONAND GROWTH DURINGTHEGROWTHPROCESS CELLSNOTONLYINCREASEINNUMBERBUTTHEYALSODEVELOP INTODIFFERENTTYPESOFCELLSTHATARENEEDEDTOFORMTHEORGANSANDTISSUESOFTHENEW INDIVIDUAL ;$U4EMPLE =  ,IFEON%ARTH 0LANET%ARTHISTHOUGHTTOBEBILLIONYEARSOLD4HEʄRSTLIFEFORMAPPEAREDABOUT BILLIONYEARSAGOBYTHESPONTANEOUSAGGREGATIONOFMOLECULESTHATRAPIDLYEVOLVED INTOMICROSCOPIC RELATIVELYSIMPLECELLS/VERTHEFOLLOWINGMILLENNIA THESEPRIMI TIVECELLSEVOLVEDINTOATLEASTMILLIONDIFFERENTSPECIES WHICHREPRESENT%ARTHȀS EXISTINGBIOLOGICALDIVERSITY!LLORGANISMS INCLUDINGANIMALS PLANTS FUNGI ANDAN UNTOLDCOLLECTIONOFMICROBIALSPECIES HAVETHEIRCOMMONANCESTRALROOTSWITHINTHESE EARLIESTLIFEFORMS&IGURE  #HEMICAL AND FOSSIL EVIDENCE INDICATES THAT LIFE ON %ARTH AS WE KNOW IT TODAY EVOLVEDBYNATURALSELECTIONFROMAFEWSIMPLECELLS CALLEDPROKARYOTESBECAUSETHEY LACKEDNUCLEI4HEEARLIESTPROKARYOTESPROBABLYALREADYHADMECHANISMSTHATALLOWED THEMTOREPLICATETHEIRGENETICINFORMATION ENCODEDINNUCLEICACIDS ANDTOEXPRESS THISINFORMATIONBYTRANSLATIONINTOVARIOUSPROTEINS4YPICALPROKARYOTICCELLSAREBAC TERIA&IGURE 4HEYARESMALL WITHRELATIVELYSIMPLEINTERNALSTRUCTURESCONTAINING DEOXYRIBONUCLEICACID$.! PROTEINS ANDSMALLMOLECULES4HEYREPLICATEQUICKLY

G. Clément, Fundamentals of Space Medicine, Space Technology Library 23, DOI 10.1007/978-1-4419-9905-4_2, © Springer Science+Business Media, LLC 2011





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Figure 2.1. One Application of Space Research Is to Improve the Health of Astronauts in Space and That of People of All Ages on Earth. The Drawing by Leonardo Da Vinci, “Proportional Study of Man in the Manner of Vitruvius,” Served as the Inspiration for Several Life Sciences Space Mission Patches, Including Skylab and Spacelab. (Source Unknown).

BYSIMPLYDIVIDINGINTWO!SINGLECELLCANDIVIDEEVERYMINANDTHEREBYGIVERISE TOBILLIONCELLSINLESSTHANH4HEIRABILITYTODIVIDEQUICKLYGROWTHRATE ENABLES THESE CELLS TO ADAPT RAPIDLY TO CHANGES IN THEIR ENVIRONMENT "ACTERIA CAN UTILIZE VIRTUALLYANYTYPEOFORGANICMOLECULEASFOOD INCLUDINGSUGARS AMINOACIDS FATS HYDROCARBONS ANDTHEYGETTHEIRENERGYINTHEFORMOFADENOSINETRIPHOSPHATE!40 FROMCHEMICALPROCESSESINTHEABSENCEORPRESENCEOFOXYGEN !BOUTBILLIONYEARSAGOTHEREAPPEAREDLARGERANDMORECOMPLEXCELLSSUCHAS THOSE FOUND IN ȃHIGHERȄ ORGANISMS THE UNICELLULAR PROTISTS FUNGI PLANTS AND THE ANIMALSWEKNOWTODAY4HEIMPORTANTORGANELLESOFENERGYMETABOLISM PLASTIDSAND MITOCHONDRIA ORIGINATEDǻBILLIONYEARSAGOTHROUGHTHESYMBIOSISOFPROKARY OTES)NTHISPROCESS BACTERIAHAVINGONESETOFSPECIALIZEDFUNCTIONSWEREENGULFED BYHOSTCELLSWITHCOMPLEMENTARYREQUIREMENTSANDFUNCTIONS4HESEEUKARYOTICCELLS ORPROTOZOA HAVEANUCLEUS WHICHCONTAINSTHECELLȀS$.! ANDCYTOPLASM WHERE MOSTOFTHECELLȀSMETABOLICREACTIONSOCCUR4HEYGETTHEIR!40FROMAEROBICOXIDA TIONOFFOODMOLECULESRESPIRATION ORFROMSUNLIGHTPHOTOSYNTHESIS #ONSEQUENTLY MORETHANBILLIONYEARSAGO THEBIOTAHADUSEDTHEPROCESSOFPHOTOSYNTHESISTO CREATE AN OXIDIZING ATMOSPHERE FROM ONE PREVIOUSLY POOR IN OXYGEN #ARBON DIOXIDEWASALSOREMOVEDFROMTHEATMOSPHEREINTHEFORMOFCARBONATEPRECIPITATES

3PACE"IOLOGY



Figure 2.2. Evolution of Organisms Deduced from Their Gene Sequences. (Source Unknown).

Figure 2.3. Escherichia coli Is the Most Well Known Bacteria. It Is Characterized by Rudimentary Chromosomes, Rapid Generation Time, and a Well-Defined Life Cycle. Like Other Bacteria, E. coli Is Able to Generate New Mutations When Challenged by Its Environment. (Source Unknown).

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!MYRIADOFBACTERIA MOLLUSKS CORALS ANDOTHERORGANISMSCONTRIBUTEDTOVASTLIME STONEDEPOSITSANDCONTINUETODOSOTODAY7ITHTHESEANDOTHERPROCESSES %ARTHȀS BIOSPHERE HAS TRANSFORMED A ONCE STERILE PLANET INTERMEDIATE IN CHARACTER BETWEEN 6ENUSAND-ARS INTOTHELIVINGPLANETWENOWENJOY "ACTERIAHAVEBEENDETECTEDORISOLATEDFROMMANYHOSTILEENVIRONMENTSON%ARTH INCLUDINGTHEDRY EXTREMELYCOLDSURFACESANDINTERSTICESOFROCKSINTHEDRYVALLEYSOF THE!NTARCTIC HOTENVIRONMENTSASSOCIATEDWITHSUBMARINEANDTERRESTRIALVOLCANOES ANDGEOTHERMALSYSTEMS ANDDEEPSUBSURFACESEDIMENTSANDAQUIFERS)NVESTIGATIONS INEXTREMETERRESTRIALENVIRONMENTSAREINTHEIRINFANCY ANDWESTILLKNOWLITTLEABOUT EITHERMOSTOFTHEORGANISMSINHABITINGTHESEENVIRONMENTS ALSOCALLEDEXTREMOPHILES ORINMANYCASESTHEGEOCHEMISTRYANDGEOPHYSICSOFTHEENVIRONMENTSTHEMSELVES .EVERTHELESS IN THE LAST DECADE OR SO A VARIETY OF NOVEL ORGANISMS HAVE BEEN ISOLATED 4HEY INCLUDE HYPERTHERMOPHILES WHICH ARE CAPABLE OF GROWING AT m# BAROPHILES CAPABLEOFGROWINGATTHEPRESSURESFOUNDINTHEDEEPESTOCEANTRENCHES AND ANAEROBES WHICH ARE CAPABLE OF USING IRON MANGANESE OR EVEN URANIUM AS ELECTRON ACCEPTORS 3IMILARLY A VARIETY OF STRATEGIES HAVE BEEN IDENTIʄED BY WHICH MICROORGANISMS CAN SURVIVE ENVIRONMENTAL CONDITIONS THAT DO NOT ALLOW GROWTH INCLUDINGLOWTEMPERATUREANDLOWNUTRIENTCONDITIONS4ABLE 

Table 2.1.

Microorganisms with Particular Physiological and Nutritional Characteristics.

Physiological Characteristic

Description

Temperature s 0SYCHROPHILE s s s s

0SYCHROTROPH -ESOPHILE 4HERMOPHILE (YPERTHERMOPHILE

s /PTIMALTEMPERATUREFORGROWTHIS—#ORLOWER RANGEn—# s #APABLEOFGROWINGAT—#ORBELOW s /PTIMALTEMPERATUREFORGROWTHIS—#RANGEn—# s 'ROWSAT—#ORABOVE s 'ROWSAT—#ORABOVERANGEn—#

Oxygen s !EROBE s !NAEROBE s &ACULTATIVE!NAEROBE

s -ICROAEROPHILE

s #ANTOLERATETOXYGENPRESENTINANAIRATMOSPHERE and has a strictly respiratory-type metabolism s 'ROWSINTHEABSENCEOFOXYGEN s #ANGROWAEROBICALLYORANAEROBICALLYnCHARACTERISTICOF a large number of genera of bacteria including coliforms such as Escherichia coli s #APABLEOFOXYGEN DEPENDENTGROWTHBUTONLYATLOW levels

pH s !CIDOPHILE s !LKALOPHILE s .EUTROPHILE

s 'ROWSATP(VALUESLESSTHAN s 'ROWSATP(VALUESGREATERTHAN s 'ROWSBESTATP(VALUESNEAR

(Continued)

3PACE"IOLOGY Table 2.1.



(Continued)

Physiological Characteristic

Description

Salinity s (ALOPHILE

s 2EQUIRESSALTFORGROWTHCLASSIlEDASEXTREMEALLARE ARCHAEA ORMODERATEHALOPHILESn.A#L

Hydrostatic Pressure s "AROPHILEATM   MDEPTH ATMBAR MPa)

s /BLIGATEBAROPHILES NOGROWTHATATMOFPRESSURE BAROTOLERANTBACTERIA GROWTHATATMBUTALSOATHIGHER pressures. Deep-sea bacteria are called barophilic if they grow optimally under pressure and particularly if they grow optimally at or near their in-situ pressure

Nutrition s !UTOTROPH s (ETEROTROPH s #HEMOORGANOHETEROTROPH s #HEMOLITHOAUTOTROPH s -IXOTROPH

s /LIGOTROPH s #OPIOTROPH

s 5SESCARBONDIOXIDEASITSSOLESOURCEOFCARBON s 5NABLETOUSECARBONDIOXIDEASITSSOLESOURCEOF CARBONANDREQUIRESONEORMOREORGANICCOMPOUNDS s $ERIVESENERGYFROMCHEMICALCOMPOUNDSANDUSES organic compound s 2ELIESONCHEMICALCOMPOUNDSFORENERGYANDUSES inorganic compounds as a source of electrons s #APABLEOFGROWINGBOTHCHEMO ORGANO HETERO TROPHICALLYANDCHEMOLITHOAUTOTROPHICALLYEXAMPLESINCLUDE SULFUR OXIDIZINGBACTERIA s #ANDEVELOPONMEDIACONTAININGMINIMALORGANIC MATERIALnPGCARBON, s 2EQUIRESNUTRIENTSATLEVELSTIMESTHOSEOF oligotrophs

!N INTERESTING ALTHOUGH ALARMING DISCOVERY WAS MADE DURING THE !POLLO P ROGRAM4HE!POLLO ,UNAR-ODULELANDEDONTHE-OONABOUTMAWAYFROM ANUNMANNEDPROBE 3URVEYOR  WHICHHADLANDEDTHEREYEARSEARLIER4HEASTRO NAUTSOF!POLLO INSPECTEDTHE3URVEYORSPACECRAFTFORDAMAGEANDRECOVEREDAN EXTERNAL CAMERA FOR DETAILED ANALYSIS BACK ON %ARTH ! SPECIMEN OF BACTERIA 3TREPTOCOCCUSMITIS WASFOUNDALIVEONTHECAMERA"ECAUSEOFTHEPRECAUTIONSTHE ASTRONAUTSHADTAKEN ITISALMOSTCERTAINTHATTHEGERMSWERETHEREBEFORETHEPROBE WAS LAUNCHED 4HIS CLEARLY DEMONSTRATES THE THREAT OF THE CONTAMINATION OF OTHER PLANETSBYAN%ARTHȀSBIOTOPE 4HESEBACTERIAHADSURVIVEDFORMONTHSINTHEVACUUMOFTHELUNARATMOSPHERE WHILEEXPOSEDTOCONSIDERABLESOLARANDCOSMICRADIATION4HEYSUFFEREDHUGEMONTHLY TEMPERATURESWINGSANDTHECOMPLETELACKOFWATER ASIFTHEYHADHIBERNATED)NFACT FREEZINGANDDRYING INTHEPRESENCEOFTHERIGHTPROTECTANTS AREACTUALLYTWOWAYS NORMAL BACTERIA CAN ENTER A STATE OF SUSPENDED ANIMATION !ND INTERESTINGLY IF THE RIGHTPROTECTANTSARENOTSUPPLIEDORIGINALLY THEBACTERIATHATDIEʄRSTSUPPLYTHEMFOR THEBENEʄTOFTHESURVIVINGONES




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,IKEWISE SPORESOFTHE"ACILLUSBACTERIAWEREFOUNDDURINGTHESUMMEROF INSALTCRYSTALSBURIEDMBELOWGROUNDATACAVERNIN.EW-EXICO7HENTHEY WEREEXTRACTEDFROMTHECRYSTALSINALABORATORYANDPLACEDINANUTRIENTSOLUTION THE MICROORGANISMSREVIVEDANDBEGANTOGROW4HESEBACTERIAHADSURVIVEDINASTATEOF SUSPENDEDANIMATIONFORMILLIONYEARS5NTILNOW THEWORLDȀSOLDESTLIVINGSURVI VORSWERETHOUGHTTOBEǻMILLION YEAR OLDBACTERIASPORESDISCOVEREDINABEE PRESERVEDINAMBER4RADITIONALLY ENDOSPOREANDCYSTDEVELOPMENTWERECONSIDERED THE PRINCIPAL MECHANISMS FOR LONG TERM SURVIVAL BY MICROORGANISMS BUT IT IS NOW CLEARTHATMANYMICROORGANISMSHAVEMECHANISMSFORLONG TERMSURVIVALTHATDONOT INVOLVESPOREORCYSTFORMATION  ,IFEON-ARS 7ITHOUTEXCEPTION LIFEIN%ARTHȀSBIOSPHEREISCARBON BASEDANDISORGANIZEDWITHINA PHASEBOUNDARYORMEMBRANETHATENVELOPSREACTINGBIOMOLECULES%VERYDOCUMENTED TERRESTRIALCELLULARLIFEFORMISASELF REPLICATINGENTITYTHATHASGENETICINFORMATIONIN THE FORM OF NUCLEIC ACID POLYMERS $.! CODING FOR PROTEINS "IOLOGICALLY ACTIVE SYSTEMS REQUIRE AT A MINIMUM LIQUID WATER CARBON NITROGEN PHOSPHATE SULFUR VARIOUSMETALS ANDASOURCEOFENERGYEITHERINTHEFORMOFSOLARRADIATIONORFROM CHEMOSYNTHETICPROCESSES 4HECONDITIONSTHATNURTUREDEARLYSELF REPLICATINGSYSTEMSANDTHEIRTRANSITIONINTO MICROBIALCELLSARESPECULATIVE)NCONTRAST ITISMUCHEASIERTOMODELTHEEARLYSTAGES OF EVOLUTION /RIGINS OF LIFE EXPERIMENTS HAVE OUTLINED THE SYNTHESIS OF THE BASIC BUILDINGBLOCKSOFLIFE INCLUDINGAMINOACIDS NUCLEOTIDES ANDSIMPLEPOLYPEPTIDES ANDPOLYNUCLEOTIDES9ETCREATIONOFSELF SUSTAINING SELF REPLICATINGBIOLOGICALENTI TIESCAPABLEOFEVOLUTIONHASNOTYETBEENACHIEVEDINTHELABORATORY%VENIFSUCCESS FUL THISACHIEVEMENTWOULDNOTNECESSARILYMIMICHOWLIFESTARTEDON%ARTHORINOTHER PARTSOFTHEUNIVERSE &ORLIFETOORIGINATE THEPRESENCEOFLIQUIDWATERANDASOURCEOFUSABLEFREEENERGY ARENECESSITIES4HESYNTHESISANDPOLYMERIZATIONOFBASICORGANICBUILDINGBLOCKSOF LIFEON%ARTHEVENTUALLYLEDTOSELF REPLICATINGNUCLEICACIDSCODINGFORPROTEINS BUT THE EARLIEST REPLICATING SYSTEMS WERE NOT NECESSARILY COMPOSED OF AMINO ACIDS AND NUCLEOTIDES )F EXTRATERRESTRIAL BIOLOGICAL SYSTEMS EXIST THEIR MODES OF INFORMATION STORAGE RETRIEVAL ANDPROCESSINGANDTHEIRENZYMATICACTIVITYMAYNOTBEIDENTICALTO THOSEOFBIOLOGICALENTITIESON%ARTH5NDERSTANDINGTHISPREBIOTICEVOLUTIONISONEOF THEMAJORGOALSOFTHEASTROBIOLOGYPROGRAM WHICHISTHESTUDYOFBIOLOGYOFTHEEARLY %ARTHANDELSEWHEREINTHEUNIVERSE )N THE SEARCH FOR EXTRATERRESTRIAL LIFE MICROBES ARE FAR MORE LIKELY THAN MULTI CELLULARORGANISMSTORETAINVIABILITYONSMALL3OLAR3YSTEMBODIESBECAUSETHEYCAN ADAPT TO A MUCH WIDER RANGE OF ENVIRONMENTAL CONDITIONS !S MENTIONED ALREADY SINGLE CELLORGANISMSSUCHASBACTERIAHAVEINʄLTRATEDVIRTUALLYEVERYCORNEROF%ARTHȀS BIOSPHERE AND STILL CONSTITUTE THE BULK OF %ARTHȀS BIOMASS 4HEY GROW IN TEMPERATE MARINEANDTERRESTRIALSETTINGS WITHINOTHERMICROBIALORMULTI CELLULARORGANISMS IN DEEPSUBSURFACENICHES ANDINEXTREMEENVIRONMENTSTHATWOULDBELETHALFOROTHER LIFE FORMS 4HEY OFTEN INʅUENCE GEOCHEMICAL REACTIONS WITHIN THE BIOSPHERE AND FREQUENTLYPLAYKEYROLESINFOODCHAINSANDCOMPLEXECOSYSTEMS

3PACE"IOLOGY



Figure 2.4. Left: ALH84001 Is by Far the Oldest Martian Meteorite, with a Crystallization Age of 4.5 Billion Years. Right: The Small Amount of Carbonate in ALH84001 Is the Center of Attention Concerning the Possibility of Life on Mars. (Credit NASA).

&IGURE  LEFT PANEL SHOWS A  BILLION YEAR OLD ROCK THAT IS A PORTION OF A ETEORITE!,( THATWASDISLODGEDFROM-ARSANDFELLTO%ARTHIN!NTARCTICA M ABOUTMILLIONYEARSAGO)TISBELIEVEDTOCONTAINFOSSILEVIDENCETHATPRIMITIVELIFE MAYHAVEEXISTEDON-ARSMORETHANBILLIONYEARSAGO4HESMALLGRAINSONTHE RIGHTPANELIN&IGUREAPPEARTOHAVEFORMEDINFRACTURESINSIDETHISROCKINTHEPRES ENCEOFLIQUIDWATEROROTHERʅUID4HEREISCONSIDERABLEDEBATEABOUTTHEORIGINOF THESECARBONATES4HESEGRAINSARETHESITESOFTHETHREETYPESOFEVIDENCETHAT-C+AY ANDHISCOLLEAGUES;-C+AYETAL =SUGGESTREPRESENTFOSSILLIFEON-ARS

 'RAVITATIONALBIOLOGY 4HROUGHOUTITSENTIREEVOLUTION LIFEON%ARTHHASEXPERIENCEDONLYA GENVIRONMENT 4HEINʅUENCEOFTHISOMNIPRESENTFORCEISNOTWELLUNDERSTOOD EXCEPTTHATTHEREIS CLEARLY A BIOLOGICAL RESPONSE TO GRAVITY IN THE STRUCTURE AND FUNCTIONING OF LIVING ORGANISMS 'RAVITATIONAL BIOLOGY AIMS TO UNDERSTAND THE MOLECULAR MECHANISMS WHEREBYACELLDETECTSGRAVITYANDCONVERTSTHISSIGNALTOANEURONAL IONIC HORMONAL ORFUNCTIONALRESPONSE  1UESTIONS (OWARECELLS ASSINGLEUNICELLULARORGANISMSORASTHEBASICUNITSOFMULTI CELLULAR ORGANISMS SENSITIVETOGRAVITYGRAVITROPISM (OWDOPLANTCELLSDETECTTHEGRAVITY VECTORANDTRANSFORMTHISFORCEINTOHORMONALANDNON HORMONALSIGNALS #HANGESINTHEPHYSICALENVIRONMENTSURROUNDINGCELLS INVIVOORINVITRO CAN LEADINDIRECTLYTOCHANGESWITHINTHECELL,ITTLEISKNOWNABOUTIFORHOWINDIVIDUAL CELLSSENSEMECHANICALSIGNALS SUCHASGRAVITY ORHOWTHEYTRANSDUCETHOSESIGNALS INTO A BIOCHEMICAL RESPONSE ! CELLULAR MECHANO SENSING SYSTEM MIGHT INITIATE CHANGESINNUMEROUSSIGNALINGPATHWAYS3PACEʅIGHTOFFERSAUNIQUEOPPORTUNITYFOR REVEALINGTHEPRESENCEOFSUCHASYSTEM



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)TISKNOWNTHATPLANTSHAVEGRAVITY SENSINGORGANSINTHEIRROOTS WHICHINVOLVE THESEDIMENTATIONOFPARTICLES THESO CALLEDSTATOLITHSORAMYLOPLASTS/N%ARTH INA ROOTTHATISPLACEDVERTICALLY THESTATOLITHSARESEDIMENTEDATTHEBOTTOMENDOFTHECELL 7HENTHEROOTISPLACEDHORIZONTALLYFORH THESTATOLITHSARETHENSEDIMENTEDONTO THELATERALWALLSOFTHECELL&IGURE 2EMOVALOFTHEROOTABOLISHESTHECAPACITYTO DETECTGRAVITY&IGURE  .OW ISITTHEMOVEMENTOFTHESTATOLITHSTHROUGHTHECYTOPLASM ORTHEPRESSURE THEY EXERT ON OTHER LOWER CELLULAR COMPONENTS THAT IS INVOLVED IN GRAVICEPTION 5NICELLULARORGANISMS LIKECILIATESPARAMECIUM ANDʅAGELLATESALGAE HAVEMEM BRANE ION CHANNELS THAT ARE ACTIVATED BY A MECHANICAL LOAD LIKE THE WEIGHT OF THE CYTOPLASM;(¡DERETAL =)NPRINCIPLE ANYMASSISSUBJECTTOTHEFORCEOFGRAVITY ANDCONSEQUENTLYCANBEREGARDEDASAGRAVITYRECEPTOR ASINDEEDTHESTATOLITHIS4HE BODY ORPROTOPLASM OFALLLIVINGCELLSISCOMPOSEDOFALARGEVARIETYOFPARTICLESAND AGGREGATES OF PARTICLES SUSPENDED IN A HETEROGENEOUS MATRIX 4HE NORMAL FORCE OF GRAVITYMAKESTHESEPARTICLESTENDTOʅOATORSINKWITHRESPECTTOTHEOTHERCELLCOM PONENTS DEPENDING ON THEIR RELATIVE DENSITIES &IGURE   4HE DENSITY OF CERTAIN ORGANELLESCANBESIGNIʄCANTLYHIGHERTHANONE WHICHISTHEAPPROXIMATEDENSITYOF CYTOPLASM#ONSEQUENTLY ATGTHEORGANELLESWILLAPPLYACERTAINPRESSUREONTHEʄLA MENTSOFTHECYTOSKELETON3UCHPRESSUREDISAPPEARSATGWITHPOSSIBLEEFFECTSONTHE INTERACTIONSBETWEENTHEPLAYERSOFTHESIGNALTRANSDUCTIONCHAINSTHATAREEMBEDDED INTHECYTOSKELETON )DENTIʄCATIONOFDIRECTGRAVITATIONALEFFECTSATTHECELLULARLEVELISCRUCIAL$IRECT EFFECTS ARE THOSE CAUSED BY THE INTERACTION OF THE FORCE OF GRAVITY WITH CELLULAR

Figure 2.5. This Schematic of the Microscopic View of the Top of a Zea Maize Root Cap Shows the Statoliths (Black Particles) Sedimented at the Bottom of the Cells. The Statoliths Migrate onto the Lateral Walls of the Cells in the Direction of the 'RAVITATIONAL&ORCEON%ARTH!DAPTEDFROM7ILKINS;]. Credit Philippe Tauzin).

3PACE"IOLOGY



Figure 2.6. Time Sequence Showing the Gravitropic Response on Earth of the Seedling Root of Zea Maize Placed Horizontally at Time Zero (Top) and Photographed After 0.5, 4, and 12 h. After Removal of the Root Cap (right), the Seed Grows Straight for At Least 12 h. !DAPTEDFROM7ILKINS;]. Credit Philippe Tauzin).

Figure 2.7. Decrease in Pressure and Loss of Sedimentation in Microgravity Compared to Normal Gravity. AboveG IN"OTH!NIMALAND0LANT#ELLS THE$ENSER)TEMSHAVE Sedimented to the Lower Part of the Cell. Below (0 g): The Cell Elements Are Almost Evenly Distributed in the Cell Volume. In Addition, the Physical Pressure and Strain ON 3TRUCTURES )S 2EDUCED !DAPTED FROM #OGOLI ET AL ;]. Credit Philippe Tauzin).



&UNDAMENTALSOF3PACE-EDICINE

S TRUCTURES AND ORGANELLES OR BY ITS ABSENCE RESPECTIVELY )NDIRECT EFFECTS ARE THOSE CAUSED BY CHANGES IN THE CELL MICROENVIRONMENT UNDER ALTERED GRAVITATIONAL CONDI TIONS)NDIRECTEFFECTSMAYBEDUETOTHEABSENCEOFCONVECTIONANDSEDIMENTATIONAT GTHATCAUSESACHANGEOFTHEDISTRIBUTIONOFNUTRIENTSANDOFWASTEPRODUCTSAROUND THECELLS;#OGOLI = )N A WORLD OF MOLECULES EMBEDDED IN ʅUIDS AND LOADED WITH ELECTRICAL CHARGES DOMINATEDBYVISCOSITYANDELECTROSTATICFORCES GRAVITYISANEXTREMELYWEAKFORCE (OWEVER THEIMPACTOFGRAVITYMAYNOTBENEGLIGIBLEINBIOLOGICALSYSTEMSTHATARE NOTSTATIC BUTINANON EQUILIBRIUMSTATUS)NABIOLOGICALPROCESSCONSISTINGOFMANY SUBSEQUENTSTEPS THEPRINCIPLEOFȃSMALLCAUSELARGEEFFECTȄAPPLIES BYWHICHASMALL PERTURBATIONOFONEOFTHESTEPSISSUFʄCIENTTOPROVOKEDRAMATICCHANGESDOWNSTREAM ASPREDICTEDBYTHEBIFURCATIONTHEORYDESCRIBED4ABONYETAL;= !LLLIVINGSYSTEMSREACTINONEWAYORANOTHERTOCHANGESOFTHEENVIRONMENTAL PARAMETERSSUCHASTEMPERATURE ILLUMINATION PRESSURE CONCENTRATIONSOFNUTRIENTS OR ACTIVATORSINHIBITORS'RAVITYISAMECHANICALFORCE#HANGEOFTHEGRAVITATIONALENVI RONMENT IE CHANGESOFTHEFORCESACTINGONTHECELL ISASIGNIʄCANTENVIRONMENTAL CHANGE )T SHOULD THEREFORE BE NO SURPRISE THAT SINGLE CELLS ALSO REACT AND ADAPT TO CHANGESFROMTOGCONDITIONS;#OGOLI = )MPORTANTCHANGESSUCHASTHELOSSOFSEDIMENTATION DENSITY DRIVENCONVECTION ANDHYDROSTATICPRESSUREAREOCCURRINGINAWEIGHTLESSCELLCULTURE&ORACELLIMMERSED INAʅUID ASITISTHECASEINACULTURE THISISACOMPLETELYNEWSITUATION&IRST ING MAMMALIAN CELLS SEDIMENT WITHIN A FEW MINUTES TO THE BOTTOM OF THE ʅASK WHERE MANY OF THEM MAY SPREAD AND ADHERE )N  G INSTEAD CELLS REMAIN IN SUSPENSION 'OINGFROMTOGISACHANGEFROMATWOǻTOATHREE DIMENSIONALENVIRONMENTAND HASAREMARKABLEIMPACTONCELLINTERACTIONS CELLMOVEMENTS AND DUETOTHELACKOF ASUBSTRATUMONWHICHTOSPREADANDADHERE ONCELLSHAPE 3ECOND DENSITY DRIVENCONVECTION WHICHISDUETOCHANGESINTHECONCENTRATION OFNUTRIENTSANDWASTEPRODUCTSINTHEMEDIUM DOESNOTOCCURINMICROGRAVITY THUS PREVENTINGMECHANICALDIFFUSION4HERMODYNAMICDIFFUSIONISNOTAFFECTED HOWEVER 4HIRD ANEWCONVECTION PREDICTEDATTHEBEGINNINGOFTHETWENTIETHCENTURYBY -ARANGONIANDNOTDETECTABLEATG BECOMESRELEVANTINMICRO GRAVITY4HELACKOF BUOYANCYPREVENTSGASBUBBLES LIKETHE#/BUBBLESDEVELOPEDBYTHEMETABOLISMOF CELLS TORISETOTHESURFACEOFACULTURE THUSFAVORINGTHEFORMATIONOFLARGERBUBBLES INTHEMIDDLEOFTHELIQUIDPHASERATHERTHANASEPARATIONOFTHELIQUIDANDGASPHASES 4HEPHYSIOLOGYOFTHECELLMAYALSOBEINʅUENCEDBYGRAVITY7HILEPASSIVETRANS PORTOFSMALLMOLECULESTHROUGHTHELIPIDBILAYERISGOVERNEDBYDIFFUSIONAGRAVITY INDEPENDENTPROCESS ACTIVETRANSPORTOFIONSANDCHARGEDMOLECULES INWHICHPROTEIN CHANNELSANDTRANSIENTMEMBRANEINVAGINATIONSAREINVOLVED MAYBEINʅUENCEDBY GRAVITY4HEBALANCEDEXCHANGEOFIONSANDMOLECULESTHROUGHCELLMEMBRANESMIGHT BESENSITIVETOGRAVITY4HESAMEMAYHOLDFORMEMBRANETURNOVER ABASICPROCESSIN CELLLIFE ANDFORINTERCELLULARDIFFUSIONOFSUBSTANCESOFVARYINGMOLECULARWEIGHT 'RAVITY MAY ALSO PLAY A ROLE IN INTERCELLULAR TRANSPORT PROCESSES )N FACT EXOTHERMIC METABOLIC PROCESSES GENERATE CONTINUOUSLY WARMER MICRO REGIONS THAT ARE LESS DENSE THAN THE NEIGHBORHOOD 4HUS THERMAL CONVECTIONS ARE PRODUCED BY GRAVITYWITHCONSEQUENTULTRA STRUCTURALREARRANGEMENTS3UCHCONVECTIONSAREOBVI OUSLYABSENTINMICROGRAVITY

3PACE"IOLOGY



!LSO THEENERGYTURNOVERINTHECELLSCANBEINʅUENCEDBYGRAVITY'RAVITYCAUSES ANUNEVENDISTRIBUTIONOFTHEORGANELLESTHATGIVESRISETOATORQUECAPABLETOMODIFY THESHAPEANDTHESTRUCTUREOFTHECELL%NERGYISREQUIREDTOMAINTAINITSSHAPEAGAINST GRAVITY)NMICROGRAVITY SUCHENERGYMAYBESAVEDFOROTHERPROCESSES SUCHASPROLIF ERATIONORBIOSYNTHESIS &INALLY FREE SWIMMING CELLS CONSUME ENERGY TO SWIM AGAINST GRAVITY TO AVOID SEDIMENTATION3UCHENERGYISNOTREQUIREDATG 4OINVESTIGATETHESEPHENOMENA RESEARCHPROGRAMSINTHEBIOLOGICALSCIENCESAND BIOTECHNOLOGYHAVEFOCUSEDONTHREEPRIMARYAREASOFINTERESTA SEPARATIONPHYSICS AIMEDATPROVIDINGIMPROVEDRESOLUTIONANDSENSITIVITYINPREPARATIVEANDBIOANALYTICAL TECHNIQUESB CELLBIOLOGY CELLFUNCTION ANDCELL CELLINTERACTIONSANDC PHYSICAL CHEMISTRYOFBIOLOGICALMACROMOLECULESANDTHEIRINTERACTIONS INCLUDINGSTUDIESOFPRO TEINCRYSTALGROWTHDIRECTEDATSUPPORTINGCRYSTALLOGRAPHICSTRUCTUREDETERMINATIONS )NTHEʄELDOFBIOTECHNOLOGY FOREXAMPLE THEABSENCEOFCONVECTIONANDSEDIMEN TATIONCANHELPTHESEPARATIONANDISOLATIONOFBIOLOGICALSPECIMENS4HEINCREASEIN SURFACE TENSION WILL IMPROVE TRANSPORT PROCESSES AND CONSEQUENTLY SECRETION AND GROWTH4HEOBJECTIVEISTOCULTIVATEPROTEINSHORMONES ENZYMES ANTIBODIES AND CELLS THAT SECRETE A MEDICALLY VALUABLE SUBSTANCE 4HE PURIʄED PRODUCT WOULD BE RETURNEDTO%ARTHFORMEDICALUSE PRODUCTCHARACTERIZATION ORIMPROVEMENTOFGROUND BASED SEPARATION TECHNIQUES (OWEVER THIS PROCESS IS NOW CHALLENGED BY GROUND BASED COMPUTER GRAPHICS MODELS AND BY GENETIC ENGINEERING TECHNIQUES LIKE THE CLONINGPROCESS THATAREMUCHLESSEXPENSIVETHANEXPERIMENTSINSPACE  2ESULTSOFSPACEEXPERIMENTS 7HENGRAVITYISALTERED BIOLOGICALCHANGESAREOBSERVEDEVENWHENCELLSAREISOLATED FROMTHEWHOLEORGANISMANDGROWNINCULTUREINVITRO 0HYSICALSCIENTISTSPREDICTED THISWOULDNOTOCCURBECAUSEGRAVITYISANEXTREMELYWEAKFORCECOMPAREDWITHTHE OTHER FUNDAMENTAL PHYSICAL FORCES ACTING ON OR WITHIN CELLS (OWEVER SPACEʅIGHT RESULTSSUGGESTTHATMICROGRAVITYMAYALTERTHECHARACTERISTICSOFCULTUREDCELLS-OST CELLSʅOWNINSPACEHAVEEITHERBEENSUSPENDEDINANAQUEOUSMEDIUMORATTACHEDTO ANEXTRA CELLULARMATRIXBATHEDBYANAQUEOUSMEDIUM  3USPENDEDCULTURES -ANYSPACEMISSIONSHAVEʅOWNBACTERIAINEXPERIMENTALCULTURES4HEʄRSTCULTURES OF%SCHERICHIACOLIʅEWONBOARDTHE53"IOSATELLITE IN-ATTONIETAL;= REPORTEDTHATAFTERA HORBITALʅIGHT THEʅIGHTPOPULATIONSGREWSIGNIʄCANTLYFASTER THANTHEGROUNDCONTROLS!NOTHERBACTERIA "ACILLUSSUBTILIS WASFOUNDTOEXHIBITAN INCREASEDDURATIONOFEXPONENTIALGROWTH ANDANAPPROXIMATEDOUBLINGOFʄNALCELL POPULATIONDENSITYCOMPAREDTOGROUNDCONTROLS;+LAUSETAL =&IGURE  0LANEL ET AL ; = DISCOVERED AN INCREASED RESISTANCE OF % COLI AND 3TAPHYLOCOCCUSAUREUSTOANTIBIOTICSWHENCULTUREDINSEVERALEXPERIMENTSINSPACE 4HEEFFECTWASATTRIBUTEDTOANINCREASEOFTHETHICKNESSOFTHECELLMEMBRANE OBSERVED IN ELECTRON MICROGRAPHS WITH CONSEQUENT DECREASE IN THE MEMBRANE PERMEABILITY 4HESERESULTSSUGGESTTHATHUMANSAREATGREATERRISKINSPACE GIVENTHATTHEREMAYBE LARGERPOPULATIONSOFBACTERIAINACONʄNEDENVIRONMENT WHICHARE MOREOVER LESS SENSITIVETOANTIBIOTICS



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Figure 2.8. Diagram Showing the Increase in Growth Rate of Bacteria (Bacillus subtilis) Cultured Aboard Skylab (0 g) by Comparison with the Same Bacteria Grown in Ambient Conditions as Skylab, But on Earth (1 g).

4HESEEFFECTSMAYSIMPLYREʅECTTHEFACTTHATWHENCHALLENGEDWITHANEWENVI RONMENT THEʄRSTRESPONSEOFBACTERIAISTOINCREASEGROWTHRATEUNTILNEWMUTATIONS APPEARTHATAREBETTERADAPTED(OWEVER THESEDIFFERENCESMAYALSOBERELATEDTOTHE LACKOFCONVECTIVEʅUIDMIXINGANDLACKOFSEDIMENTATION BOTHPROCESSESTHATREQUIRE GRAVITY7EALREADYMENTIONEDTHATTHEMAJOREFFECTOFREDUCEDGRAVITYENVIRONMENTS ISAREDUCTIONINGRAVITATIONALBODYFORCES THUSDECREASINGBUOYANCY DRIVENʅOWS RATESOFSEDIMENTATION ANDHYDROSTATICPRESSURE5NDERSUCHCONDITIONS OTHERGRAVITY DEPENDENTFORCES SUCHASSURFACETENSION ASSUMEGREATERIMPORTANCE4HESEALTERA TIONSINʅUIDDYNAMICSINAREDUCEDGRAVITYENVIRONMENTHAVESIGNIʄCANTIMPLICATIONS &OREXAMPLE INCELLCULTUREEXPERIMENTS THEDIFFUSIONOFNUTRIENTS OXYGEN GROWTH FACTORS ANDOTHERREGULATORYMOLECULESTOTHEPLASMAMEMBRANE ASWELLASTHEDIFFU SIONOFWASTEPRODUCTSAND#/AWAYFROMTHECELL WILLBEREDUCEDINTHENEARABSENCE OFCONVECTIONUNLESSCOUNTEREDBYSTIRRINGORAFORCEDʅOWOFTHEMEDIUM )TISTHOUGHTTHAT INREDUCEDGRAVITY THEMOREUNIFORMDISTRIBUTIONOFSUSPENDED CELLSMAYINITIALLYINCREASENUTRIENTAVAILABILITYCOMPAREDTOTHESEDIMENTINGCELLSAT GTHATCONCENTRATEONTHECONTAINERBOTTOMAWAYFROMAVAILABLENUTRIENTSREMAINING INSOLUTION4HISPHENOMENONWOULDINCREASEGROWTHRATE(OWEVER IFWASTEPRODUCTS BUILDUPAROUNDCELLSINTHEABSENCEOFGRAVITY THENAFTERSOMETIMETHEYCOULDPOTEN TIALLYFORMAPSEUDO MEMBRANETHATDECREASESTHEAVAILABILITYOFNUTRIENTSORDIRECTLY INHIBITSCELLMETABOLISM)TISSUGGESTEDTHATINHIBITORYLEVELSOFMETABOLICBYPRODUCTS SUCH AS ACETATE MAY BE FORMED WHEN GLUCOSE IS IN EXCESS WITHIN THE MEDIUM 4HEREFORE ALTHOUGH PERHAPS SOMEWHAT COUNTER INTUITIVE A REDUCTION IN GLUCOSE

3PACE"IOLOGY



A VAILABILITY ACTUALLY MAY BE BENEʄCIAL TO CELL GROWTH !LSO LOCAL TOXIC BYPRODUCTS COULDBECOMECONCENTRATEDONTHEBOTTOMOFTHE GCONTAINERWITHCELLSININCREASED PROXIMITY TO EACH OTHER 3UCH A PROCESS COULD LIMIT CELL GROWTH 4HUS CHANGES IN BACTERIAANDPOSSIBLYOTHERCELLSDURINGSPACEʅIGHTMAYBERELATEDTOALTERATIONSINTHE MICROENVIRONMENTSURROUNDINGNON MOTILECELLS EG THEEQUILIBRIUMOFEXTRA CELLULAR MASS TRANSFERPROCESSESGOVERNINGNUTRIENTUPTAKEANDWASTEREMOVAL3UCHCHANGES APPEARTOBETYPICALINDIRECTEFFECTSOFGRAVITYCAUSEDBYCHANGESOFTHEMICROENVIRON MENTOFTHECELLS 4HECURRENTVIEWISTHATAȃCUMULATIVEȄRESPONSERESULTINGFROMREDUCEDGRAVITY MAYBERESPONSIBLEFORTHEOBSERVEDEFFECTSATTHELEVELOFTHESINGLECELL%ARLIERPRE DICTIONSSUGGESTINGTHATNOEFFECTOFSPACEʅIGHTSHOULDBEEXPECTEDWEREMOREFOCUSED ONTHEPHYSICALINABILITYOFGRAVITYTOELICITANIMMEDIATEORȃDIRECTȄRESPONSEFROM ORGANISMS OF SUCH SMALL MASS 2ATHER THAN A ȃDIRECTȄ RESPONSE REDUCED GRAVITY IS SUSPECTEDTOINITIATEACASCADEOFEVENTSTHEALTEREDPHYSICALFORCELEADSTOANALTERED CHEMICALENVIRONMENT WHICHINTURNGIVESRISETOANALTEREDPHYSIOLOGICALRESPONSE ;+LAUS = 3ACCHAROMYCES CEREVISIAE THE YEAST USED TO BAKE BREAD AND CAKES IS A HIGHLY APPRECIATED ORGANISM IN THE STUDY OF SEVERAL ASPECTS OF EUKARYOTIC CELL LIKE SIGNAL TRANSDUCTION GENETIC EXPRESSION AND ADAPTATION TO ENVIRONMENTAL STRESS )T HAS THE GREATADVANTAGEOFBEINGRESISTANTTOROUGHENVIRONMENTALCONDITIONSLIKEFREEZINGOR LACKOFNUTRIENTS)TALSOHASBIOLOGICALPROPERTIESANDBEHAVIORANALOGOUSTOTHOSEOF MAMMALIANCELLSTHATARE BYCONTRAST MUCHMORESENSITIVETOTHEENVIRONMENTAND THEREFOREMUCHMOREDIFʄCULTTOKEEPALIVEINSPACEEXPERIMENTS4HEANALOGYWITH MAMMALIANCELLSPERMITSTHEINVESTIGATIONOFCRUCIALBIOLOGICALPROCESSES INCLUDING CANCERINYEASTCELLS)NADDITION YEASTISWIDELYUSEDINBIOTECHNOLOGICALPROCESSES INPARTICULARINGENETICENGINEERING4HEREFORE ITISNOTSURPRISINGTHATYEASTCELLSHAVE BEENEXTENSIVELYCHOSENFOREXPERIMENTSINSPACE 7ITHTHEINCREASINGINTERESTINBIOPROCESSINGINSPACETHEREQUIREMENTFORSOPHIS TICATEDCELLCULTUREANDTISSUEENGINEERINGFACILITIES ALSOKNOWNASBIOREACTORS TOBE INSTALLEDINSPACELABORATORIESWASOBVIOUS3PACEBIOREACTORSWEREʄRSTDEVELOPED USINGYEASTCELLSTHATAREEASYTOCULTIVATEANDTOPRESERVEINSTEADOFDELICATEANDSENSI TIVEMAMMALIANCELLS.OWTHATTHEINSTRUMENTATIONHASPROVENADEQUATE THEEXPERI MENTATIONWITHMAMMALIANCELLSANDTISSUECANBEGIN  !TTACHEDCELLS %ARLYRESULTSWITHCULTUREDCELLSFROMMUSCLESORBONESSUGGESTTHATSPACEʅIGHTINDUCES AWIDEVARIETYOFRESPONSES&OREXAMPLE DELAYEDDIFFERENTIATIONANDCHANGESINTHE CYTOSKELETON NUCLEARMORPHOLOGY ANDGENEEXPRESSIONHAVEBEENREPORTEDFORBONE CELLS;(UGHES &ULFORDAND,EWIS =-USCLEʄBERSCULTUREDINSPACEWEREǻ THINNERIE ATROPHIED COMPAREDWITHGROUNDCONTROLSDUETOADECREASEINPROTEIN SYNTHESISRATHERTHANANINCREASEINPROTEINDEGRADATION;6ANDENBURGHETAL = )NTERESTINGLY THEATROPHYOFISOLATEDMUSCLEʄBERSINCULTUREWASVERYSIMILARTOTHE AMOUNT OF MUSCLE ATROPHY REPORTED IN ʅIGHT ANIMALS SEE #HAPTER  3ECTION   4HESEDATAFROMBONEANDMUSCLECELLSSUGGESTTHATSPACEʅIGHTAFFECTSADHERENTCELLS ANDTISSUESEVENWHENISOLATEDFROMSYSTEMICFACTORS4HESAMERESULTSWEREOBTAINED DURINGGROUND BASEDSTUDIESUSINGCLINOSTATS&IGURE 



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Figure 2.9. The Clinostat Is a Simple Device that Places a Plant, a Small Organism, or Cell Growing in Culture on a Rotating Platform. The Rotation Causes the Biosystem 5NDER 4EST TO BE 3UBJECTED TO THE 'RAVITY 6ECTOR FROM !LL $IRECTIONS &ROM THE System’s Point of View, the Rotation Cancels the Gravity Vector by Continuous !VERAGING THUS!PPROXIMATINGTHE(IGHLY2EDUCED6ECTOR&OUNDINTHE!CTUAL3PACE Environment. (Credit CNES).

#HANGES IN THE PHYSICAL ENVIRONMENT SURROUNDING CELLS IN VIVO OR IN VITRO CAN LEAD INDIRECTLY TO CHANGES WITHIN THE CELL #ELLULAR STRUCTURES THAT MIGHT OPPOSE MECHANICALLOADINGAREONLYBEGINNINGTOBEDEʄNED%XCITINGRESEARCHONTHEINTERAC TIONOFTHECELLCYTOSKELETONWITHMEMBRANECOMPONENTSANDTHEEXTRA CELLULARMATRIX ISSHEDDINGLIGHTONPOSSIBLEȃFORCESENSORSȄATTHECELLULARLEVELTHATMIGHTBEESSEN TIAL FOR THE DIFFERENTIATION PROCESS ;7AYNE ET AL = )NGBER ; = HAS APPLIEDTHECONCEPTOFȃTENSIONALINTEGRITYȄ WHICHISATENSION DEPENDENTFORMOFCEL LULARARCHI TECTURETHATORGANIZESTHECYTOSKELETONANDSTABILIZESCELLULARFORM TOCELLS 4HISARCHITECTUREMAYBETHECELLULARSYSTEMTHATINITIATESARESPONSETOMECHANICAL LOADINGASARESULTOFSTRESS DEPENDENTCHANGESINSTRUCTURETHATALTERTHEMECHANICAL LOADONEXTRA CELLULARMATRIX CELLSHAPE ORGANIZATIONOFCYTOSKELETON ORINTERNALPRE STRESSBETWEENCELLANDTISSUEMATRICES 4HECONSENSUSOFPHYSICALCHEMISTSPRIORTOTHISDECADEWASTHATFORCESEXERTED BETWEENMOLECULESWITHINACELLWEREFARGREATERTHANGRAVITATIONALFORCES4HUS THEY CONCLUDED THAT GRAVITY SHOULD NOT BE PERCEIVED AT THE CELLULAR LEVEL ;"ROWN = (OWEVER ATTHATTIMEVERYLITTLEWASKNOWNABOUTHOWCELLSINTERACTEDWITHCOMPO NENTS OF THE EXTRA CELLULAR ENVIRONMENT 4HESE INTERACTIONS MIGHT FUNCTION TO EITHER SUPPRESSORAMPLIFYSIGNALSGENERATEDBYGRAVITATIONALLOADING$EʄNINGTHECELLULAR CONNECTIONS THAT MIGHT SENSE AND TRANSDUCE MECHANICAL SIGNALS INTO A BIOCHEMICAL RESPONSEMAYALSOSHEDLIGHTONTHEEVENTSINITIATINGCELLMATURATION!SACELLMATURES ITSTOPSDIVIDINGANDBEGINSTOEXPRESSCHARACTERISTICSOFAMATURECELLTYPE(OWEVER IFACELLDOESNOTMATURE ITWILLCONTINUETODIVIDE4HISISTHEDEʄNITIONOFACANCERCELL

3PACE"IOLOGY



4HEMATURATIONPROCESSMAYBETRIGGEREDBYMULTIPLEFACTORS INCLUDINGLOADSPLACEDON THEEXTRA CELLULARMATRIXDURINGDIFFERENTPHASESOFDEVELOPMENT )NSUMMARY ʅIGHTEXPERIMENTSSUGGESTTHATGRAVITY QUITELIKELY ISPERCEIVEDBY CELLS THROUGH PHYSICAL CHANGES BOTH IN THE AQUEOUS MEDIUM SURROUNDING CELLS IN CULTUREANDINCELLULARSTRUCTURESTHATOPPOSEORSENSEMECHANICALLOADS%XACTLYHOW THEGRAVITYSIGNALISTHENTRANSDUCEDTOCELLULARFUNCTIONSISYETTOBEDETERMINED4HE ANSWER TO THIS QUESTION IS NOT ONLY RELEVANT TO UNDERSTANDING THE FUNDAMENTAL PRO CESSESINNORMALCELLPHYSIOLOGY BUTALSOINTHEPATHO PHYSIOLOGYOFCERTAINDISEASES SUCHASAGE RELATEDBONELOSS CANCER ORIMMUNEDISORDERS;"OUILLONETAL =  4HRESHOLDFORGRAVITYPERCEPTION 4HECHANGESINTHESWIMMINGBEHAVIOROFCILIATESANDʅAGELLATES WHICHPRESUMABLY COMPENSATEPARTOFTHECHANGESINTHECELLPHYSICALPROPERTIESINGEG SEDIMENTA TION THERMALCONVECTION CANBEMEASUREDFORCALCULATIONOFTHESENSITIVITYTOGRAVITY PERCEPTION;-ACHEMERETAL =)N ASOPHISTICATEDSLOWROTATINGCENTRIFUGE MICROSCOPE CALLED.):%-)FOR.IEDERGESCHWINDIGKEIT:ENTRIFUGE-IKROSKOP DEVEL OPEDBYTHE'ERMAN3PACE!GENCY MEASUREDTHEMINIMALIN ʅIGHTACCELERATIONTHAT WASABLETOINDUCEAGRAVICEPTIVERESPONSEINMICROORGANISMS4HEFOLLOWINGACCEL ERATIONTHRESHOLDWEREOBTAINED0ARAMECIUM G%UGLENA ANDGAND ,OXODES LESSTHANG)NTERESTINGLY THERESULTSWERESIMILARWHENTHECELLSWERE SUBJECTEDEITHERTOINCREASINGORDECREASINGACCELERATIONS ANDTHEEFFECTWASINDEPEN DENTOFTHEPREVIOUSEXPOSURETOMICROGRAVITYUPTODAYS ALTHOUGHTHECELLSUNDER WENTSEVERALDIVISIONCYCLES "ECAUSETHEORGANELLESUSEDFORGRAVITY SENSINGMECHANISMSINTHESEORGANISMS SHOWSOMEANALOGYTOTHESTATOLITHSINPLANTSANDTHEOTOLITHSINHUMANSANDOTHER VERTEBRATES THERESULTSOFTHESESTUDIESONTHRESHOLDFORGRAVITYPERCEPTIONAREOFFUN DAMENTALIMPORTANCEFORDETERMININGTHEOPTIMALLEVELOFARTIʄCIALGRAVITYFORLONG DURATIONHUMANMISSIONS  (UMANBLOODCELLS !LTHOUGH THE REPORTS TO DATE ARE CONʅICTING SOME INDICATE THAT A MICROGRAVITY ENVIRONMENTMAYCOMPROMISETHEIMMUNESYSTEMFUNCTION4HESEINVESTIGATIONSARE CARRIEDOUTONCULTURESOFLYMPHOCYTESPREPAREDONTHEGROUNDANDTESTEDINSPACE AND WITH WHOLE BLOOD SAMPLES TAKEN FROM THE CREW AND TESTED IN ʅIGHT RESPECTIVELY &IGURE   #OGOLI ET AL ;= REPORTED THAT CULTURES OF HUMAN LYMPHOCYTES SUBJECTED TO MICROGRAVITY RESPONDED TO CONCANAVALIN ! A LYMPHOCYTE STIMULATING AGENT LESSTHANGROUND BASEDCONTROLS4HISISASTANDARDTESTUSEDTOEVALUATE THECOMPETENCEOFPERIPHERALBLOODLYMPHOCYTESTOMULTIPLYWHENSTIMULATEDWITH THISAGENT3TUDIESONTHEASTRONAUTSOFTHEʄRSTFOURSPACESHUTTLEʅIGHTSREVEALEDTHAT THE LYMPHOCYTE RESPONSES TO PHOTOHEMAGGLUTININ ANOTHER LYMPHOCYTE STIMULATING AGENT WEREREDUCEDFROMTOOFNORMALFOLLOWINGSPACEʅIGHT)THASBEEN SUGGESTEDTHATTHEABOVECHANGESWEREDUETOSTRESS RELATEDEFFECTS BUTTHISSHOULDBE STUDIEDFURTHER 4HESESTUDIESAREIMPORTANTBECAUSE ASWASDISCUSSEDEARLIER THECONCENTRATIONS OF MICROORGANISMS IN SPACE VEHICLES MAY BE SIGNIʄCANTLY HIGHER THAN NORMAL 4HE CONDITIONSASSOCIATEDWITHSPACETRAVEL SPACESTATIONS ANDPLANETARYCOLONIESRAISE



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Figure 2.10. A Crewmember Insert Blood Test Samples in a Refrigerated Centrifuge in the Columbus Laboratory of the International Space Station. (Credit NASA).

MANY NEW AND IMPORTANT PROBLEMS CONCERNED WITH HOST PARASITE INTERACTIONS INVOLVINGHUMANSANDANIMALS2OTATIONOFCREWMEMBERSONTHE)33WILLINTRODUCE DIFFERENTSTRAINSOFFUNGI BACTERIA ANDVIRUSESTHATCOULDCONTRIBUTETOTHEEMERGENCE OFȃNEWȄSTRAINSOFOPPORTUNISTICPATHOGENSTHROUGHMUTATIONANDGENETICEXCHANGE #LEARLY SPACEʅIGHT IS ASSOCIATED WITH A SIGNIʄCANT INCREASE IN THE NUMBER OF CIRCULATINGWHITEBLOODCELLS INCLUDINGNEUTROPHILES MONOCYTES 4 HELPERCELLS AND "CELLS)NCONTRAST THENUMBEROFNATURALKILLERCELLSISDECREASED0LASMANOREPINEPH RINELEVELSAREINCREASEDATLANDINGANDARESIGNIʄCANTLYCORRELATEDWITHTHENUMBEROF WHITEBLOODCELLS;-ILLSETAL =4HESEDATASUGGESTTHATTHESTRESSOFSPACEʅIGHT AND LANDING MAY LEAD TO A SYMPATHETIC NERVOUS SYSTEM MEDIATED REDISTRIBUTION OF CIRCULATINGLEUKOCYTES ANEFFECTPOTENTIALLYATTENUATEDAFTERLONGERMISSIONS7HETHER HEMATOPOESIS ORTHEMATURATIONOFLYMPHOCYTES ISCOMPROMISEDISYETTOBEESTAB LISHED4HEMULTIPLESTRESSESOFSPACEʅIGHTMAYALSOLEADTOHORMONALIMBALANCES AND CORTICOSTEROIDRELEASEMAYLEADTOIMMUNO SUPPRESSION/OGENESISANDSPERMATOGEN ESIS IE THEFORMATIONOFFEMALEANDMALESEXUALGAMETES MAYALSOBECOMPROMISED )NANYCASE ADDITIONALRESEARCHISREQUIREDTOCONʄRMORREJECTTHEPRESENCEOFTHESE PROBLEMS /NTHEOTHERHAND THEREISASIGNIʄCANTREDUCTIONINTHEPERCENTOFWHOLEBLOOD THATISCOMPRISEDOFREDBLOODCELLSHEMATOCRIT INSOMEASTRONAUTS4HEHEMATOCRIT IS A COMPOUND MEASURE OF RED BLOOD CELLS NUMBER AND SIZE 4HIS REDUCTION IN THE NUMBEROFREDBLOODCELLSINASTRONAUTSISOFTENREFERREDASTHESPACEANEMIA4HIS REDUCTIONMAYBEDUETOSEVERALFACTORS7HILEINSPACE THEOVERABUNDANCEOFʅUIDS INTHEUPPERPARTOFTHEBODYCAUSESTHEKIDNEYSTOREMOVETHISEXCESSʅUID PARTOF WHICH IS PLASMA SEE #HAPTER  3ECTION   4HIS REDUCTION IN PLASMA VOLUME CAUSESANOVER ABUNDANCEOFOXYGEN CARRYINGCAPABILITY WHICH INTURN WOULDREDUCE THEPRODUCTIONOFERYTHROPOIETINANDCONSEQUENTLYDECREASEREDBLOODCELLPRODUCTION

3PACE"IOLOGY



4HISPROCESSWOULDBEFAVOREDBYTHEFACTTHATMUSCLESLOSEMASSANDTHUSREQUIRELESS OXYGEN (OWEVER IT IS ALSO POSSIBLE THAT THE OVER ABUNDANCE OF OXYGEN CARRYING CAPACITYINTHEBLOODISRESPONSIBLEFORANINCREASEINTHEDESTRUCTIONRATEOFREDBLOOD CELLS&INALLY ASWEWILLSEEIN#HAPTER ASASTRONAUTSLOSECALCIUMINTHEIRBONES THESTRUCTUREANDFUNCTIONOFTHEBONEANDITSMARROWMAYCHANGEANDMAYRESULTINA DECREASEINREDBLOODCELLPRODUCTION  "IOPROCESSINGINSPACE 2ESEARCHINBIOTECHNOLOGYRELIESONTHEMANIPULATIONOFCELLSOFLIVINGORGANISMS4HE PURPOSEOFTHESEMANIPULATIONSISTOPRODUCEUSEFULMOLECULES NATURALORARTIʄCIAL IN USEFULQUANTITIES TODEVELOPNEWORGANISMSORNEWBIOLOGICALMOLECULESFORSPECIʄC USES OR TO IMPROVE YIELDS OF PLANT AND ANIMAL PRODUCTS THROUGH GENETIC ALTERATION 2ECOMBINANTTECHNIQUES FOREXAMPLE MAKEITPOSSIBLETOPRODUCENATURALORARTIʄCIALLY MUTATEDVERSIONSOFPROTEINSEXHIBITINGAWIDERANGEOFACTIVITIESANDUSES SCIENTIʄCAND MEDICAL INLARGEQUANTITIES4HETECHNIQUESESSENTIALTOTHESEMANIPULATIONSAREAPPLIED INAQUEOUSENVIRONMENTSANDARESUBJECTTOʅUIDDYNAMICSANDTRANSPORTPROCESSES 'RAVITYAFFECTSBIOLOGICALSYSTEMSTHROUGHITSINʅUENCEONTHETRANSFEROFMASS ANDHEAT PARTICULARLYINTHEAREAOFʅUIDDYNAMICSANDTRANSPORT ASWELLASITSIMPACT ONCELLSTRUCTUREANDFUNCTION&IGURE #ONSEQUENTLY MICROGRAVITYMAYLEADTO NEWKNOWLEDGEABOUTBIOLOGICALSYSTEMS TOIMPROVEMENTSINCURRENTEXPERIMENTAL TECHNIQUES AND TO THE DEVELOPMENT OF NEW EXPERIMENTAL APPROACHES %XAMPLES INCLUDEFERMENTATIONPROCESSES COMPARTMENTALTARGETINGOFEXPRESSEDPRODUCTSWITHIN THECELL ANDTHEULTIMATEPURITY STRUCTURALINTEGRITY ANDACTIVITYOFAPROTEINPRODUCT 0ARTICLESEDIMENTATIONUNDERTHEINʅUENCEOFGRAVITY FOREXAMPLE CANINTERFERE WITHAGGREGATIONPROCESSESSUCHASTHOSEMEDIATINGCELL CELLINTERACTIONS CELLFUSION CELLAGGLUTINATION ANDCELLULARINTERACTIONSWITHSUBSTRATES

Figure 2.11. Schematic Comparison Between Body (Left) and Cell (Right) Functions, Showing that Biological Processes That Occur at Cellular Level Are Similar to Those at Organism Level. (Credit Philippe Tauzin).



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!DETAILEDKNOWLEDGEOFTHETHREE DIMENSIONALARCHITECTURESOFBIOLOGICALMACRO MOLECULESISREQUIREDFORAFULLUNDERSTANDINGOFTHEIRFUNCTIONS ANDOFTHECHEMICAL ANDPHYSICALEFFECTSTHATTHEYMANAGETOACHIEVETHESEFUNCTIONS4OBEABLETOSYNTHE SIZENEWPROTEINS WHETHERFORMEDICALUSESORASCOMPLEXBIOMATERIALS ITISNECESSARY TO BE ABLE TO RELATE MOLECULAR STRUCTURE AND FUNCTION 0ROTEIN CRYSTALLOGRAPHY CUR RENTLYTHEPRINCIPALMETHODFORDETERMININGTHESTRUCTUREOFCOMPLEXBIOLOGICALMOL ECULES REQUIRESRELATIVELYLARGE WELL ORDEREDSINGLECRYSTALSOFUSEFULMORPHOLOGY #RYSTALSWITHTHESEQUALITIESMAYBEDIFʄCULTTOPRODUCEFORAVARIETYOFREASONS SOME OFWHICHMAYBEINʅUENCEDBYGRAVITY THROUGHDENSITY DRIVENCONVECTIONANDSEDI MENTATION0ROTEINCRYSTALGROWTHEXPERIMENTSCONDUCTEDONBOARDTHESPACESHUTTLE &IGURE HAVEPROVIDEDPERSUASIVEEVIDENCETHATIMPROVEMENTSCAN INFACT BE REALIZEDFORAVARIETYOFPROTEINSAMPLES 4HEREARETWOTYPESOFBIOLOGICALMATERIALSFORWHICHCOMMERCIALBIOPROCESSING IN SPACE COULD OFFER ADVANTAGES OVER PRODUCTION ON %ARTH PROTEINS AND CELLS 4HE PROTEINSINCLUDEHORMONES ENZYMES ANTIBODIESANDVACCINES4HECELLSWITHMEDICAL PROSPECTSAREA THOSETHATWHENCULTIVATED SECRETEAMEDICALLY VALUABLESUBSTANCE THATCANBEISOLATEDEITHERINSPACEORON%ARTHB THOSETHATCANBEIMPLANTEDINMAN FORTHERAPEUTICPURPOSESANDC THOSETHAT THROUGHCELLFUSION CANYIELDANTIBODY PRODUCINGHYBRIDCELLS;"ONTINGETAL = (OWDOESSPACEBIOPROCESSINGWORK4HERAWMATERIAL WHETHERAPROTEINMIXTURE ORAMIXTUREOFLIVINGCELLS ISBROUGHTINTOSPACEANDSEPARATEDINMICROGRAVITYTHE PURIʄEDPRODUCTISTHENRETURNEDTO%ARTHFORMEDICALUSE PRODUCTCHARACTERIZATION OR IMPROVEMENT OF A GROUND BASED PROCESSING TECHNIQUE 4ABLE  LISTS SOME OF THE MEDICALPRODUCTSTHATCOULDBEOBTAINEDTHROUGHBIOPROCESSINGINSPACE (OWEVER THECONTINUOUSPRODUCTIONOFSUCHBIOLOGICALMATERIALSONACOMMERCIAL SCALE IN SPACE PROVED NOT COMPATIBLE WITH THE COST FOR ACCESS TO SPACE AND SPACE

Figure 2.12. Zeolites Have a Rigid Crystalline Structure with a Network of Interconnected Tunnels and Cages, Similar to a Honeycomb.:EOLITES(AVETHE!BILITYTO!BSORB ,IQUIDSAND'ASES3UCHAS0ETROLEUMOR(YDROGEN -AKING4HEMTHE"ACKBONE of the Chemical Processes Industry. Industry Wants to Improve Zeolite Crystals so that More Gasoline can be Produced from a Barrel of Oil. The Zeolite Crystals Grown on the Ground (Left) Are Smaller Than Those Grown in Space (Right). The :EOLITE#RYSTAL'ROWTH&URNACE5NIT!BOARDTHE)33!LLOWSTO'ROW:EOLITE#RYSTALS and Zeo-Type Materials in Space. (Credit NASA).

3PACE"IOLOGY Table 2.2.



Some Candidate Biological Materials for Space Processing and their Medical Prospects [Bonting et al., 1989].

Materials

Condition

s !LPHA  ANTITRYPSIN

s %MPHYSEMA

s !NTIHEMOPHILIC&ACTOR

s (EMOPHILIA

s "ETACELLS0ANCREAS

s $IABETES

s %PIDERMAL'ROWTH&ACTOR

s "URNS

s %RYTHROPOIETIN

s !NEMIA

s 'RANULOCYTE3TIMULATING&ACTOR

s 7OUND(EALING

s 'ROWTH(ORMONE

s 'ROWTH0ROBLEMS

s )MMUNOGLOBULINS

s )MMUNE$ElCIENCY

s )NTERFERON

s 6IRAL)NFECTIONS

s 4RANSFER&ACTOR

s -ULTIPLE3CLEROSIS

s 5ROKINASE

s 4HROMBOSIS

B IOPROCESSINGREMAINSMARGINALTODAY&URTHERMORE GROUND BASEDGENETICENGINEER INGINMAMMALIANORHUMANEMBRYOCELLSISNOWAVERYSTRONGALTERNATIVETOSPACE BIOPROCESSING TOGETHERWITHPURIʄCATIONMETHODSSUCHASAFʄNITYORIMMUNO AFʄNITY CHROMATOGRAPHYANDHIGH PRESSURELIQUIDCHROMATOGRAPHY!LSO ALTERNATIVESTO8 RAY CRYSTALLOGRAPHYAREEMERGING USINGPHYSICALANDMATHEMATICALMODELSANDCOMPUTER GRAPHICS THAT ARE EQUALLY USEFUL IN DETERMINING THE THREE DIMENSIONAL STRUCTURE OF PROTEINS

 $EVELOPMENTBIOLOGY 4HEMAJORGOALFORDEVELOPMENTALBIOLOGYISTODETERMINEWHETHERANYORGANISMCAN DEVELOPFROMFERTILIZATIONTHROUGHTHEFORMATIONOFVIABLEGAMETESREPRODUCTIVECELLS INTHENEXTGENERATION IE FROMEGGTOEGG INTHEMICROGRAVITYANDRADIATIONENVIRON MENTOFSPACE)NTHEEVENTTHATNORMALDEVELOPMENTDOESNOTOCCUR THEPRIORITYISTO DETERMINEWHICHPERIODOFDEVELOPMENTISMOSTSENSITIVETOMICROGRAVITY  1UESTIONS #ANHIGHERPLANTSANDANIMALSBEPROPAGATEDTHROUGHSEVERALGENERATIONSINTHESPACE ENVIRONMENT !LTHOUGH MANY EMBRYOS ORIENT THEIR CLEAVAGE PLANES RELATIVE TO THE GRAVITYVECTOR WEDONOTUNDERSTANDWHETHERGRAVITY PERSE ISESSENTIALTOGAMETO GENESIS FERTILIZATION IMPLANTATION IN ANIMALS ORGANOGENESIS OR DEVELOPMENT OF NORMALSENSORY MOTORRESPONSES'IVENTHEEFFECTSOFMICROGRAVITYEXPOSUREONBONE MUSCLE ANDVESTIBULARFUNCTION THEREISSOMEDOUBTWHETHERVERTEBRATESCANDEVELOP NORMALLYINSPACE 4HE AMPHIBIAN HAS BEEN USED AS A MODEL FOR MANY EXPERIMENTS ON EMBRYONIC DEVELOPMENTINSPACE;3OUZAETAL =)N8ENOPUSLAEVIS THE3OUTH!FRICANTHREE CLAWEDFROG FOREXAMPLE THEUNFERTILIZEDEGGHASAPOLARIZEDSTRUCTUREBECAUSEOFAN



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UNEQUALDISTRIBUTIONOFTHEYOLKTHEANIMALPOLEISPOORINYOLK WHEREASTHEVEGETATIVE POLECONTAINSLARGEQUANTITIES"EFOREFERTILIZATION THEEGG SURROUNDEDBYALAYEROF JELLY ISORIENTEDRANDOMLY!FTERFERTILIZATION THEWHOLEEGGDETACHESITSELFFROMTHIS LAYERANDROTATES SOTHATTHEHEAVIERVEGETATIVEPOLEMOVESDOWNWARDS INTHEDIRECTION OFGRAVITY6ERYROUGHLY THEANIMALPOLECORRESPONDSTOTHEHEAD ANDTHEVEGETALPOLE CORRESPONDSTOTHEDORSALSIDE&IGURE !NHOURORSOAFTERFERTILIZATION ASECOND ROTATIONOCCURSTHECORTEXROTATESBYRELATIVETOTHECYTOPLASM4HISROTATIONESTAB LISHESTHEDORSO ANTERIORAXISOFTHEANIMAL4HEEGGTHENBEGINSTODIVIDEANDFORMTHE EMBRYOTHAT AFTERANAPPROPRIATETIME EMERGESFROMTHEJELLY LIKEEGGASATADPOLE 4HECORTEXROTATIONDEPENDSONATRANSIENTARRAYOFPARALLELMICROTUBULESATTHE VEGETAL CORTEX ! KINESIN LIKE PROTEIN IS ASSOCIATED WITH THE MICROTUBULES AND IS THOUGHTTOMOVETHECORTEXALONGTHEMICROTUBULES ANCHOREDINTHECYTOPLASM;%LINSON ETAL =4HECORTEXROTATIONCANBEINʅUENCEDBYGRAVITYINSEVERALWAYS&IRST EXTREMESOFGRAVITY CAUSEDBYCENTRIFUGATION CANOVERCOMETHEMICROTUBULEMECHA NISM AND PRODUCE A DORSO ANTERIOR AXIS ON THE CENTRIPETAL SIDE ;"LACK AND 'ERHART =3ECOND GRAVITYALONECANPRODUCEADORSO ANTERIORAXISINTHEABSENCEOFTHE MICROTUBULEMECHANISM;3CHARFAND'ERHART =4HIRD GRAVITYALONECANORIENT THEMICROTUBULESPRIORTOTHEIRFORMATION THEREBYDIRECTINGWHERETHEDORSO ANTERIOR AXISWILLFORM;:ISCKINDAND%LINSON ='RAVITYINTHESECASESACTSBYMOVINGTHE HEAVYYOLK RICHCYTOPLASMDOWNWARD PRODUCINGACYTOPLASMICREARRANGEMENT 4HESEGRAVITYEFFECTSHAVELEDTOREPEATEDATTEMPTSTOPLACEFROGEGGSINSPACEIN ORDERTOSEEHOWTHEYDEVELOPINMICROGRAVITY)NTHEMOSTSUCCESSFULOFSUCHEXPERI MENTS THERE WAS LITTLE OR NO PERTURBATION OF THE DORSO ANTERIOR AXIS ;3OUZA ET AL =!NORMALHEADFORMED INDICATINGTHATSOMEFORMOFCYTOPLASMICREARRANGE MENTHADOCCURRED4HISARRANGEMENTWASLIKELYDUETOTHEFUNCTIONINGOFTHEPARALLEL

Figure 2.13. The Fertilized Egg of a Common Amphibian Is Shown as It Develops from Single Cell to Larva and Adult. Cell Constituents of the Egg Are Segregated by $ENSITYnTHE$ARK ,ESS$ENSE-ATERIAL2ISESTOTHE5PPER(ALFOFTHE3PHERE While the Denser Light-Colored Material Settles to the Bottom. Continued $EVELOPMENTOFTHE%MBRYO&OLLOWS4HIS/RIENTATION#REDIT.!3! 

3PACE"IOLOGY



MICROTUBULEMECHANISM/NEPOSSIBILITYISTHATGRAVITY INDUCEDREARRANGEMENTISAN EVOLUTIONARILY PRIMITIVE MECHANISM WHICH SUBSTITUTES FOR THE MICROTUBULE MECHA NISM)FTHEREWEREANYFROGSLACKINGTHEMICROTUBULEMECHANISM THEIREGGSWOULDBE INTERESTINGOBJECTSTOPUTINSPACETHEHYPOTHESISISTHATTHEDORSO ANTERIORAXISWOULD BEALTEREDINTHERESULTINGSPACETADPOLES $EVELOPMENTALBIOLOGYALSOINCLUDESALLASPECTSOFTHELIFESPANOFANORGANISM FROMFERTILIZATIONTHROUGHAGING4OPICSOFRESEARCHINCLUDEGAMETEPRODUCTION FERTIL IZATION EMBRYOGENESIS IMPLANTATIONINMAMMALS THEFORMATIONOFORGANSORGANO GENESIS ANDPOSTNATALDEVELOPMENTCHANGESAFTERBIRTH 4HEROLEOFGRAVITYINTHESE PROCESSESISENTIRELYUNKNOWN&OREXAMPLE WEDONȀTKNOWIFCELLDIVISIONMITOSIS ANDTHEORIENTATIONOFBILATERALSYMMETRYAREINʅUENCEDBYGRAVITY )TISKNOWNTHATATSOMEPOINTAFTERFERTILIZATION DIFFERENTINDIVERSEORGANISMS CELLSBECOMECOMMITTEDTODEVELOPINGALONGACERTAINPATHWAY4HISRESTRICTIONINFATE ISCALLEDDETERMINATION$URINGEARLYCELLDIVISIONSINMOSTANIMALEMBRYOS THEREARE GRADUALRESTRICTIONSINDEVELOPMENTALPOTENTIALITY4HISISNOTTHECASEINPLANTS3OONER ORLATERINALLANIMALSTHECELLSINTHEEMBRYOCANUSUALLYGIVERISEONLYTOACERTAIN TISSUE OR ORGAN 4HEY HAVE LOST THEIR PLURAL POTENTIALITIES 4HIS SECOND PROCESS OF DEVELOPMENTISDIFFERENTIATION ATERMTHATDESIGNATESTHEPROCESSESWHEREBYTHEDIF FERENCES THAT WERE ȃDETERMINEDȄ BECOME MANIFEST 4HE MECHANISMS BY WHICH THE DETERMINATIONANDDIFFERENTIATIONOCCURATTHERIGHTTIMETOPRODUCETHENORMALORGAN ISMSISCALLEDTHEFORMATIONOFPATTERN IE NOTONLYDOTHEYREALIZETHEIRFATES BUTTHEY DOSOINTHECORRECTPLACEATTHECORRECTTIME 4HEFORMATIONOFTHEVARIOUSTISSUESANDORGANS ORORGANOGENESIS NOTONLYSPANS SEVERALDEVELOPMENTALSTAGES BUTALSOCONTINUESAFTERBIRTHORHATCHINGANDINTOTHE NATALPERIOD&OREACHORGANSYSTEM THEREAPPEARSTOBEACRITICALPERIODDURINGWHICH DEVELOPMENTCANBEDISRUPTEDBYRELATIVELYSMALLENVIRONMENTALSTRESSES4HESYSTEMS AFFECTEDBYWEIGHTLESSNESSINTHEADULT EG VESTIBULARAPPARATUS BONEMETABOLISM ANDTHEFORMATIONOFBLOODCELLS MIGHTSUFFERMORESEVEREANDMOREPERMANENTEFFECTS IFTHEGRAVITYSTIMULUSWEREWITHDRAWNDURINGTHEAPPROPRIATESTAGEOFORGANOGENESIS 4HISWOULDBESIMILARTOTHERESULTSOFTHEEXPERIMENTSINDICATINGTHATTHERECEPTORSOF THEVISUALSYSTEM THEIRNEURALCONNECTIONS ANDTHEVISUALCORTEXDEVELOPABNORMALLY INANIMALSRAISEDINCOMPLETEDARKNESS;)MBERT = &URTHER THETRANSITIONFROMTHENEONATALPERIODTOADULTHOODISMARKEDBYFUNDA MENTAL DEVELOPMENTAL EVENTS SUCH AS CELL SPECIALIZATION CELL CELL INTERACTIONS THE DEVELOPMENTANDINTEGRATIONOFMANYPHYSIOLOGICALANDBIOCHEMICALFUNCTIONS AND GROWTH&IGURE &OREXAMPLE RADICALCHANGESINTHESTRUCTUREANDCONNECTIONS OFNEURONSOCCURDURINGTHEDEVELOPMENTOFTHENERVOUSSYSTEM&ROMTISSUELAYERS FOUNDINEMBRYONICANIMALS CELLSINCREASEINNUMBERANDEVENTUALLYDIFFERENTIATEAND MIGRATETOTHEIRAPPROPRIATEFUNCTIONANDPOSITIONINTHEDEVELOPINGNERVOUSSYSTEM )NALL UPTOOFNEURONSARELOSTBYTHEPROCESSOFAPOPTOSIS ORPROGRAMMEDCELL DEATHDURINGDEVELOPMENT4HOSETHATREMAINMUSTFORMSYNAPSESWITHCOMMUNICAT INGNEURONS"ECAUSETHESEPROCESSESAREREGULATEDBYBOTHCHEMICALANDMECHANICAL FACTORS GRAVITYMAYPLAYACRUCIALROLEASASTIMULUSFORPROPERDEVELOPMENT 2EGENERATIVEPROCESSESAREALSOFUNDAMENTALDEVELOPMENTALRESPONSESTOPOSTNA TALTISSUELOSSANDINJURY)NMANYSITUATIONS THESEPROCESSESARESIMPLYRESPONSESTO CHANGES IN THE ENVIRONMENT TO WHICH THE INDIVIDUAL IS EXPOSED 5NDERSTANDING THE



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Figure 2.14. Comparison Between the Embryonic Development of Fish, Salamander, Chick, and Human (from Left to Right, Respectively). The Early Stages (Drawn to Scale) Are Closely Similar Among Species. The Later Stages (Not Drawn to Scale) Are More Divergent. (Source Unknown).

ROLEOFGRAVITYNOTONLYINONTOGENY THEDEVELOPMENTOFTHEINDIVIDUAL BUTALSOIN PHYLOGENY WHICHISTHEEVOLUTIONOFSPECIES JUSTIʄESTHESTUDIESONVARIOUSSPECIESIN SPACEFORSUCCESSIVEGENERATIONSOVERLONGPERIODSOFTIME"YACTINGONTHISEXTERNAL FACTOR WOULDITTHENBEPOSSIBLETOMODIFYTHEBLUEPRINTSCONTAINEDINTHEGENOMEAND CHANGESOMECHARACTERSOFTHESPECIES)NOTHERWORDS WOULDWEALLBECOMEBONE LESS JELLYʄSH LIKEORGANISMS AFTERMANYGENERATIONSINSPACE  2ESULTSOFSPACEEXPERIMENTS $IVERSEORGANISMSHAVEBEENSUBJECTEDTOMICROGRAVITYFORVARYINGPERIODSOFTIME 4HERESULTSOFTHESESTUDIESHAVEBEENINCONSISTENT"OTHNORMALANDABNORMALDEVEL OPMENTSHAVEBEENOBSERVED DEPENDINGONTHEORGANISMANDTHESTAGEOFDEVELOP MENTATWHICHTHEMATERIALWASSUBJECTEDTOMICROGRAVITY-OREOVER INTHESTUDYOF EMBRYONICMATERIALINPARTICULAR MOSTEXPERIMENTSHAVEBYNECESSITYBEENPERFORMED WITHEGGSTHATWEREFERTILIZEDONTHEGROUND WELLBEFOREORBITALʅIGHT SOTHATTHECRITI CALG SENSITIVETIMEPERIODIMMEDIATELYAFTERFERTILIZATIONWASSPENTATG!LSO IN MANYEXPERIMENTS THEOTHERENVIRONMENTALFACTORS SUCHASLAUNCHANDRE ENTRYFORCES ATMOSPHERE ANDRADIATIONLEVEL WERENOTADEQUATELYCONTROLLED

3PACE"IOLOGY



 )NVERTEBRATES "ECAUSEAQUATICSPECIESNORMALLYLIVEINANEUTRALLYBUOYANTENVIRONMENT THEYSHOULD BELESSSUSCEPTIBLETOMICROGRAVITYTHANTERRESTRIALSPECIES(OWEVER ITHASBEENSHOWN THATTHEFORMATIONOFSKELETALHARDPARTSSHELLS SPICULES THATINVOLVECALCIUMCARBON ATEISALTEREDDURINGDEVELOPMENTINMICROGRAVITY"YSTUDYINGTHESEASCALLOPCALCIʄ CATIONPROCESS FOREXAMPLE SCIENTISTSHOPETOLEARNMOREOFTHEMECHANICSBEHIND BONE DENSITY LOSS IN HUMANS DURING LONG DURATION SPACEʅIGHT SEE #HAPTER  3ECTION APROBLEMCLOSELYRELATEDTOOSTEOPOROSISHEREON%ARTH 3EAURCHINSAREALONG STANDING WIDELYUSEDMODELFORSTUDYINGTHEBIOLOGYOF FERTILIZATION#OMMONGENETICORIGINS ORHOMOLOGIES BETWEENTHESEAURCHINSYSTEM ANDMAMMALIANSYSTEMSMAKETHESEAURCHINAGOODMODELFOROBTAININGBASICINFOR MATIONTHATCANPOINTTOIMPORTANTQUESTIONSTOBEADDRESSEDBYSTUDYINGMAMMALIAN SYSTEMS3EAURCHINSPERMALSOPROVIDESTHEADDEDBENEʄTOFSURVIVABILITYTHESEANI MALSAREABLETOTOLERATEDELAYSTHATSOMETIMESOCCURWITHʅIGHTRESEARCH!SERIESOF EXPERIMENTSCARRIEDOUTINSPACEUSINGTHE%3!"IO2ACKFACILITYINDICATEDTHATMICRO GRAVITYCAUSEDANINCREASEINSPERMMOTILITY(OWEVERITHASNOTBEENDEMONSTRATEDIF THISINCREASEINMOTILITYALLOWSTHESPERMTOGETTOTHEEGGSMOREQUICKLYANDFERTILIZE BETTER;4ASHETAL = *ELLYʄSHSERVEASEXCELLENTSUBJECTSFORRESEARCHONGRAVITY SENSINGMECHANISMS BECAUSE THEIR SPECIALIZED GRAVITY SENSING ORGANS HAVE BEEN WELL CHARACTERIZED BY BIOLOGISTS *ELLYʄSH%PHYRAE THAT DEVELOPED IN MICROGRAVITY HAD SIGNIʄCANTLY MORE ABNORMALARMNUMBERSASCOMPAREDWITH GʅIGHTCENTRIFUGED ANDGROUNDCONTROLS !SCOMPAREDTOCONTROLS %PHYRAETHATDEVELOPEDINSPACESHOWEDABNORMALITIESIN SWIMMINGBEHAVIORWHENTESTEDPOSTʅIGHT(OWEVER THEMEANNUMBERSOFSTATOLITHS ANDPULSESPERMINUTEASDETERMINEDPOSTʅIGHTDIDNOTDIFFERSIGNIʄCANTLYFROMCON TROLS%PHYRAETHATWEREʅOWNAFTERDEVELOPINGON%ARTHTENDEDTOSHOWCHANGESIN THEIRGRAVITY SENSINGORGANSTOO3TUDIESONGRAVITYTHRESHOLDCONDUCTEDINTHEONBOARD CENTRIFUGEREVEALEDTHATMORETHANOFTHEANIMALSCONVERTTO%ARTH LIKESWIM MING BEHAVIOR UPON EXPOSURE TO  G 4HE SWIMMING BEHAVIOR OF BOTH %PHYRAE HATCHEDON%ARTHANDINMICROGRAVITYSHOWEDTHATTHEYHADDIFʄCULTYORIENTINGTHEM SELVESINSPACE;3OUZAETAL = %XPERIMENTSONTHEFRUITʅY$ROSOPHILAMELANOGASTERDURINGA DAY6OSTOKMIS SION REVEALED THAT MATING IS POSSIBLE WITHOUT GRAVITY AND THAT DEVELOPMENTAL PRO CESSESANDMORPHOGENESISWERENORMALINMICROGRAVITY.EMATODES#AENORHABDITIS ELEGANSSUCCESSFULLYREPRODUCEDTWICEINSPACEANDGENERATEDTHOUSANDSOFOFFSPRING ;.ELSON ET AL = (OWEVER THE MATING ACTIVITY OF MALES OF THE PARASITIC WASP (ABROBRACONWASSEVERELYDISRUPTED ANDTHECAPABILITYFORTHEIREGGSTOHATCHINORBIT WAS DECREASED 3TUDIES ON GYPSY MOTH HAVE BEEN PERFORMED TO STUDY THE EFFECT OF MICROGRAVITYONTHEDIAPAUSECYCLE$IAPAUSEISTHEDORMANTPERIODINANINSECTLIFE CYCLEWHENITISUNDERGOINGDEVELOPMENTINTOITSNEXTPHASE2ESULTSSHOWTHATMICRO GRAVITY SHORTENS THE DIAPAUSE CYCLE OF GYPSY MOTHS AND LEADS TO THE EMERGENCE OF LARVAETHATARESTERILE4HECAPABILITYTOPRODUCESTERILELARVAEMAYLEADTOTHEDEVELOP MENTOFANATURALFORMOFPESTCONTROL !CCORDINGTOTHELAWSOFAERODYNAMICS INSECTSCANNOTPRODUCEENOUGHLIFTPRES SURETOʅY4HEMECHANISMWHEREBYTHEYACHIEVEʅIGHTMUSTINVOLVEUNSTEADYʅOWS INTERACTINGWITHTHEDYNAMICALLYCHANGINGWINGSURFACES)NTERESTINGLY EXPERIMENTS



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CARRIEDOUTONINSECTSINSPACEHAVESHOWNTHATLARVAEOFFRUITʅYTHATDEVELOPEDIN SPACE DID NOT LEARN TO ʅY AND PREFERRED TO ʅOAT WITHOUT BEATING THEIR WINGS 7ING ABNORMALITIESANDMUTATIONSHAVEALSOBEENREPORTEDINʅOORBEETLEWHENEXAMINED AFTER SPACEʅIGHT 3IMILARLY HONEYBEES WERE UNABLE TO ʅY NORMALLY AND TUMBLED IN WEIGHTLESSNESSWITHNOWINGBEAT 0ERHAPSTHEMOSTFAMOUSSPACEEXPERIMENTUSINGINVERTEBRATESISTHEONECARRIED OUTON3KYLABINTOASCERTAINWHETHERTWOCOMMONCROSSSPIDERS!RACHNOUS DIADEMATUS SPINWEBSDIFFERENTLYINMICROGRAVITY"ECAUSETHESPIDERSENSESITSOWN WEIGHTWHENCONSTRUCTINGTHEWEBTODETERMINETHEREQUIREDAMOUNTOFSILKTOMAKE THEWEB ITWASTHOUGHTTHATGRAVITYPLAYEDANIMPORTANTROLEINTHECONSTRUCTIONOFTHE WEB3TUDIESWERECARRIEDOUTINSPACEDURING3KYLAB 3PACELAB AND)33MISSIONS 2ESULTSSHOWEDTHATDURINGTHEIRʄRSTATTEMPTINSPACE THEWEBSWEREDIFFERENTFROM GROUNDCONTROLS BUTLATERTHEWEBSWERENEARLYIDENTICAL;3UMMERLIN =(OWEVER ALTHOUGHTHESPIDERSDIDNOTSPINTHEIRWEBPATTERNSDIFFERENTLY&IGURE ITSEEMS THATTHETHREADSTHEMSELVESWEREDIFFERENT

Figure 2.15. Left: The Common Spider Produces a Web of Nearly Concentric Circles Each Day at Approximately the Same Time. The Web Is Constructed in a Very Orderly Fashion, Starting with a Bridge and Frame (a–d), and Axial Threads (e–i). Spiral Emanating from the Hub Is Constructed Next (j–l) [Summerlin, 1977]. Right: We Proposed an ISS Experiment Using Agelena Labyrinthica, Which Produces a Sheet Web with a Three-Dimensional Funnel Shaped Retreat Spun Above It. Each Segment of the Spider Housing Will be Illuminated by a Sheet Laser and Recorded by Dual Cameras for Three-Dimensional Analysis. The Spider Housing Will be Mounted on Rails and Will Automatically Move Toward the Cameras After Each Picture Is Taken.

3PACE"IOLOGY



4HESPIDERSUSEDINTHESEPREVIOUSSPACESTUDIESWEREORB WEAVERS WHOSEWEBS WEREMOSTLY TWO DIMENSIONAL IE THE UPPER ANDTHE LOWER PARTIN ORB WEBS DIFFER ONLYINSHAPEANDNOTINFUNDAMENTALSTRUCTURE ASITISTHECASEINTHREE DIMENSIONAL WEBS 7E HAVE PROPOSED AN )33 EXPERIMENT IN WHICH SPIDERS THAT BUILD THREE DIMENSIONALWEBSTRUCTURESWOULDBEʅOWN"ASEDONRECENTDISCOVERIESTHATPERCEP TIONOFDEPTHANDHEIGHTISALTEREDINMICROGRAVITYANDTHATTHEREISANALTERATIONINTHE MENTALREPRESENTATIONOFPHYSICALSPACEWHENTHEGRAVITATIONALREFERENCEISREMOVED ;#L¦MENTAND2ESCHKE =WEHYPOTHESIZETHATTHESPIDERSWILLBEHAVELIKEASTRO NAUTS DURING EXPOSURE TO MICROGRAVITY #ONSEQUENTLY THE SHAPE AND THE SPEED FOR BUILDINGTHREE DIMENSIONALWEBSSHOULDBEAFFECTEDDURINGEARLYEXPOSURETOMICRO GRAVITY"UTAFTERLONGEREXPOSURETHEANIMALSSHOULDUSEOTHERSTRATEGIESTOBUILDTHE SAMETHREE DIMENSIONALWEBSASTHEYDOON%ARTH)NFACT ITISEVENPOSSIBLETHATTHE WEBSBUILTINSPACEAFTERCOMPLETEADAPTATIONWOULDBETHEMOSTPERFECTOFTHREE DIMENSIONAL STRUCTURES ! DETAILED ANALYSIS OF THE STRATEGIES USED BY THE SPIDERS TO BUILDTHESEPERFECTWEBSANDTHEIRʄNALDESIGNWILLBEEXTREMELYUSEFULFORARACHNOLO GISTS ARCHITECTS ARTISTS ANDENGINEERS 4HEREISASTRONGINTERESTONTHEPARTOFINDUSTRYINADVANCEDCOMPOSITEMATERIALS 3PIDERSILKISANULTRA LIGHTWEIGHTʄBERTHATCOMBINESENORMOUSTENSILESTRENGTHWITH ELASTICITY%ACHʄBERCANSTRETCHOFITSLENGTHANDABSORBAHUNDREDTIMESASMUCH ENERGYASSTEELWITHOUTBREAKING3PIDERSHAVESPECIALIZEDREARLEGS WHICHARECAPABLE OFAPPLYINGTHESTICKYSILKWITHOUTADHERINGTOIT%NGINEERSWOULDLIKETODEVELOP SYSTEMSTHATMIMICTHEACTIONOFTHESELEGS WHICHAREKNOWNINENGINEERINGASAN ȃEND EFFECTORȄ !NEXPERIMENTISALSOPLANNEDTOUSESCORPIONSONBOARDTHE)33)TISKNOWNTHAT THECIRCADIANPATTERNSINANIMALSANDHUMANSAREALSOINʅUENCEDBYACTIVITIESSUCHAS FOODINTAKEANDLOCOMOTION4HEEXPOSUREOFSCORPIONSTOMICROGRAVITYWILLHELPTO ANALYZEENTRAININGANDCOUPLINGMECHANISMSOFBIOLOGICALCLOCKSANDWILLCONTRIBUTE TOTHEANALYSISOFDISTURBANCESOFCLOCKSYSTEMSINHUMANS BYFULLYAUTOMATICMEA SUREMENTOFPHYSIOLOGICALPARAMETERSWITHCIRCADIANPATTERNS WHICHINCLUDELOCOMO TION EYE MOVEMENTS / CONSUMPTION AND CARDIO VASCULAR ACTIVITY 3CORPIONS REPRESENTANINTERESTINGANIMALMODELBECAUSETHEYCANTOLERATEACOMPLETELACKOF FOODANDWATERFORMORETHANMONTHSWITHOUTNUTRITIONALCARE4HEANIMALSWILLBE CONNECTEDTOSENSORSANDELECTRODESANDEXPOSEDTOMICROGRAVITY  G ANDDIFFERENT LIGHTREGIMES;7ILSON = 3NAILS "IOMPHALARIA GLABRATA ALSO ʅEW ON SEVERAL OCCASIONS ONBOARD SPACE SHUTTLEAND)33MISSIONS/NORBITVIDEORECORDINGREVEALEDTHATTHESNAILSWEREEAS ILYDISLODGEDFROMTHEAQUARIUMWALL WHILEON%ARTHTHEYSPENTMOSTOFTHEIRTIME ATTACHEDTOTHEWALLS/NCESEPARATEDFROMTHEWALLTHEYʅOATEDTHROUGHTHEWATER WHICHGAVETHEMTHECHANCETOCONTACTOTHERSNAILSINORBIT!STHESESNAILSAREHER MAPHRODITES MATINGPAIRSWEREOFTENSEENʅOATINGATTACHEDTOONEANOTHER!FTER THESPACECRAFTLANDED EMBRYOSOFALLDEVELOPMENTALSTAGESWEREPRESENT;-ARXEN ETAL =  ,OWERVERTEBRATES .OVERTEBRATESHAVEEVERBEENRAISEDFROMCONCEPTIONTOSEXUALMATURITYINTHEABSENCE OF GRAVITY .O BIRDS OR REPTILES HAVE BRED ON ORBIT ALTHOUGH FERTILIZED CHICKEN AND



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QUAIL EGGS HAVE ʅOWN ON SEVERAL OCCASIONS 9OUNG CHICK EMBRYOS HAVE SURVIVED 1UAILEGGSTHATWEREFERTILIZEDONTHEGROUNDHAVEHATCHEDONTHE-IRSPACESTATION BUTYIELDEDHATCHLINGSTHATWEREDISORIENTEDANDWOULDNOTORCOULDNOTSPONTANE OUSLYFEED;*ONES = 3TUDIESOFSEAURCHINS ʄSH FROGS ANDNEWTS;$OURNONETAL -OODYAND 'OLDEN = INDICATE THAT FERTILIZATION CAN OCCUR IN SPACE BUT IN THESE CASES THE GAMETESHADBEENDEVELOPEDWHILETHEORGANISMWASON%ARTH)NMOSTOFTHESESTUD IES HOWEVER MATINGANDINSEMINATIONWASPERFORMEDONTHEGROUNDBEFORELAUNCH )NSEMINATEDFEMALESSTORETHESPERMINACOMPARTMENTOFTHEBODYCALLEDSPERMATOTH ECAANDUSETHESPERMCELLSATTHEMOMENTOFEGGDEPOSITION4HEADVANTAGEOFTHIS APPROACHISTHATTHETIMEOFFERTILIZATIONANDTHEREFORETHEAGEOFEMBRYOSCANPRE CISELYBEDETERMINEDBYTHEEXPERIMENTER 4HISTYPEOFFERTILIZATIONWASSUCCESSFULLYPERFORMEDINSALAMANDERS0LEURODELES WALTL ANDNEWTS#YNOPSPYRRHOGASTER ONBOARD3PACELAB -IR ANDTHE)33;)ZUMI +UROTANIAND+IYOMOTO =4HEFEMALENEWTSKEEPSPERMATOZOAINTHEIRCLOACAE READYTOFERTILIZEEGGSAFTERHORMONALSTIMULATIONOFOVULATION%GGLAYINGTHENOCCURS WITHINǻH4HEPRESENCEOFSPERMATOZOAINTHEPERIVITELLINESPACEANDOFSPER MATICSPOTSONTHESURFACEOFTHEEGGSINMICROGRAVITYCANBECONSIDEREDASAPROOF THATTHEDEVELOPMENTOFEMBRYOSISNOTBASEDONPARTHENOGENESIS$URINGTHESEEXPER IMENTS ABOUTOFEGGSWERESUCCESSFULLYFERTILIZED"YCOMPARISON THEGROUND EXPERIMENTSREVEALEDARATIOOF SUGGESTINGTHATOCCURRENCEOFEGGFERTILIZATION WAS NOT AFFECTED BY MICROGRAVITY ;!IMAR ET AL = 5SING THE SAME METHOD IN ʅIGHTFERTILIZATIONINHOUSECRICKETS!CHETADOMESTICUSWASPERFORMEDONBOARDTHE )33 IN  !FTER THE ʅIGHT EMBRYOS WERE RECOVERED SUGGESTING THAT EGGS COULD DEVELOPFORDAYSINMICROGRAVITY &EMALE FROGS WERE SENT INTO SPACE AND INDUCED TO SHED EGGS THAT WERE THEN ARTIʄCIALLYINSEMINATED!SALREADYMENTIONED THEEGGSDIDNOTROTATE EVENTHOUGH THECORTEXDID ANDYET SURPRISINGLY THETADPOLESEMERGEDANDAPPEAREDNORMAL4HERE WERE ABNORMALITIES NOTED AT THE CELLULAR LEVEL THOUGH !FTER RETURNING TO %ARTH THE TADPOLESMETAMORPHOSEDANDMATUREDINTONORMALFROGS3UBSEQUENTEMBRYONICSTUD IESREVEALEDTHATTHECLEAVAGERHYTHMDURINGDEVELOPMENTAPPEAREDNORMAL YETSOME MORPHOLOGICAL CHANGES OCCURRED IN FROG EMBRYOS AND TADPOLES &IGURE   4HE EMBRYOHADATHICKERBLASTULAROOFTHATSHOULDHAVECREATEDABNORMALITIESINTHETAD POLE BUTNODEFORMATIONSAPPEARED SUGGESTINGPLASTICITYOFTHEEMBRYO;3OUZAETAL $UPRATETAL = !NOTHERINTERESTINGʄNDINGWASTHATTHETADPOLESDIDNOTINʅATETHEIRLUNGSDURING SPACEʅIGHT%ARTHOR GSPACECENTRIFUGED TADPOLESSWAMTOTHESURFACE GULPEDAIR ANDEXPANDEDTHEIRLUNGSWITHINǻDAYSOFHATCHING!IRBUBBLESWEREPRESENTINTHE 7HENACOSMONAUTTOOKAHATCHLINGFROMITSHABITAT THECHICKAPPEAREDCONTENTASLONGASITWASHELD"UT ONCERELEASED THEBIRDʄRSTʅAPPEDITSWINGSFORORIENTATIONANDBEGANTOSPINLIKEABALLERINA THENKICKED ITSLEGS CAUSINGITTOTUMBLELIKEASPINNINGBALL4HECOSMONAUTNOTEDTHATTHECHICKWOULDʄXITSEYESON THECOSMONAUTWHILETRYINGTOORIENTINSPACE7HENPLACEDINTHEIRHABITAT THECHICKSHADDIFʄCULTYʅYING TOTHEIRPERCHTOEAT AND UNLIKETHEADULTS HADDIFʄCULTYGRASPINGTHEPERCHFORSTABILITYWHENEATING4HE HATCHLINGSATENORMALLYONLYWHENHELDBYTHECREWAND THUS DIDNOTSURVIVE"YCONTRAST ADULTQUAILS ADAPTEDQUICKLYTOTHESPACEENVIRONMENT4HEYSOARED RATHERTHANʅAPPINGTHEIRWINGS ANDHELDONTOTHEIR PERCHFORSTABILITYWHENEATING



3PACE"IOLOGY



Figure 2.16. Comparison in the Development of Amphibian Eggs from Pleurodele Newt on Earth and in Space. There Are Clear Abnormalities in Orbit, Such as Larger Sillons AND/DD.UMBEROF#ELLS INTHE&LIGHT3PECIMENSBY#OMPARISONWITHTHE'ROUND #ONTROLS!DAPTEDFROM'UALANDRIS 0ARISOTETAL;2002]).

TADPOLEAQUATICHABITATONORBIT YETTHETADPOLESDIDNOTINʅATETHEIRLUNGSWHILEIN MICROGRAVITY4WOPOSSIBLEEXPLANATIONSFORTHESEʅIGHTʄNDINGSINCLUDELACKOFDIREC TIONALCUESANDINCREASEDINʅUENCEOFSURFACETENSIONTHATMAYMAKEITMOREDIFʄCULT FORANORBIT BORNTADPOLETOBURSTTHROUGHABUBBLEANDGULPAIR4HETADPOLESRETURNED TO%ARTHWITHINǻDAYSOFEMERGINGFROMTHEEGG ANDTHELUNGSAPPEAREDNORMALBY THETIMETHETADPOLESWERE DAYOLD;7ASSERSUG =/NEINVESTIGATIONHASSUG GESTEDTHATGAMETESFORMEDINSPACEARENORMAL;)JIRI =)NTHISEXPERIMENT -EDAKA ʄSHMATEDFREELYINMICROGRAVITYANDTHESUBSEQUENTDEVELOPMENTALSTEPSWERESIMILAR INʅIGHTANDGROUND CONTROLʄSH.EWLYLAIDEGGSFORMEDACLUSTERONTHEBELLYOFTHE FEMALEʄSH&IGURE !FTERDETACHMENTFROMTHEFEMALEȀSBODY YOUNGʄSHHATCHED INMICROGRAVITYANDSWAMNORMALLYBOTHINSPACEANDAFTERRETURNINGTO%ARTH"ACKON THEGROUND THEOFFSPRINGPRODUCEDHEALTHYSECOND GENERATIONANIMALS 4HESESTUDIESPRODUCEDMULTIPLEIMPORTANTʄNDINGS4HEYSHOWTHATVERTEBRATES CANBEINDUCEDTOOVULATEINSPACEANDTHATROTATIONOFFERTILIZEDEGGSISNOTREQUIRED FORNORMALDEVELOPMENTINSPACE,ONG DURATIONMICROGRAVITYEXPOSURESTUDIESONTHE )33REVEALEDTHATLARVAEWEREABLETOREGULATETHEMORPHOLOGICALCHANGESTHATOCCUR DURINGDEVELOPMENTALINMICROGRAVITY4HEVERTEBRATEEMBRYOISVERYADAPTIVEANDTHE SYSTEM IS PLASTIC YET THE LONG TERM FATE OF THE ANIMAL THROUGHOUT ITS LIFE IN SPACE REMAINSUNKNOWN  -AMMALS 7HENINVESTIGATIONSADDRESSHUMANADAPTATIONTOSPACEʅIGHTANDITSHEALTHIMPLICA TIONS THE USE OF OTHER MAMMALIAN SPECIES OFTEN BECOMES NECESSARY 4HE RAT IS THE



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Figure 2.17. In the Summer of 1994, Four Japanese Killifish (Medaka) Flew for 15 days on Board the Space Shuttle Columbia (IML-2; STS-65).4HESE&ISH-ATEDIN3PACE FOR THE &IRST 4IME !MONG 6ERTEBRATE !NIMALS a) and Laid Eggs (b), Which $EVELOPED.ORMALLYAND(ATCHEDAS&RYc !DAPTEDFROM)JIRI;= 

MAMMAL EMPLOYED MOST FREQUENTLY FOR SPACE RESEARCH )TS WELL DEMONSTRATED BIOCHEMICALANDSTRUCTURALSIMILARITYTOHUMANSMAKESTHERATANAPPROPRIATESUBJECT WITHWHICHTOTESTNEWDRUGSANDINVESTIGATEMANYDISORDERSEXPERIENCEDBYASTRO NAUTSDURINGANDAFTERSPACEʅIGHT7ITHINA WEEKPERIOD WHICHCORRESPONDSTOA SPACESHUTTLEʅIGHT THERATNEONATESGOTHROUGHACRITICALDEVELOPMENTPERIOD DURING WHICH RAPID NEURAL AND MOTOR DEVELOPMENT OCCURS &IGURE   !LSO BECAUSE OF THEIRPHYLOGENETICPROXIMITYTOHUMANS NON HUMANPRIMATES SUCHASRHESUSMON KEYS HAVEOCCASIONALLYSERVEDASRESEARCHSUBJECTSINSPACEBIOLOGY BUTONLYWHEN THENEEDHASBEENCLEARLYDEMONSTRATED;3OUZAETAL = &ERTILIZATIONEVENTSHAVEBEENSTUDIEDINSEVERALSPECIESFORWHICHFERTILIZATION OCCURSEXTERNALLY SUCHASNEWTORʄSH!SPREVIOUSLYDISCUSSED THEDATAINDICATETHAT FORTHESEANIMALS PRODUCTIONOFAZYGOTEANDEARLYCLEAVAGESAREMOSTLYNORMALIN THESPACEENVIRONMENT&ERTILIZATIONEVENTSINMAMMALSHAVENOTBEENSTUDIED PRI MARILYBECAUSETHEYOCCURINTERNALLY/NSEVERALOCCASIONS HOWEVER PREGNANTRATS ʅOWNINSPACEGAVEBIRTHTONORMALNEONATESAFTERʅIGHT)TWASOBSERVEDTHATDURING POSTʅIGHT DELIVERY ʅIGHT DAMS HAVE TWICE AS MANY ABDOMINAL CONTRACTIONS AS THE GROUND CONTROLS SUGGESTING THAT MORE EXTENDED EXPOSURE TO SPACEʅIGHT COULD STILL HAVEADETRIMENTALEFFECTONPREGNANCY ORATLEASTTHEBIRTHINGPROCESS;2ONCAAND !LBERTS =)NADDITION MALERATSMATEDDAYSAFTERʅIGHTTONON SPACEEXPERI ENCEDFEMALESPRODUCEDOFFSPRINGWITHGROWTHRETARDATIONANDMANYABNORMALITIES SUCHASHYDROCEPHALY OUTOFPLACEKIDNEYS ANDENLARGEMENTOFTHEBLADDER-ATING TWOANDAHALFTOMONTHSAFTERTHESPACEʅIGHTPRODUCEDHEALTHYANDVIABLEOFFSPRING ;4OUETAL = &ERTILIZATION MIGHT ALSO BE AFFECTED BY MOBILITY CHANGES IN SPERM )N FACT IT IS KNOWN THAT BULL SPERM SWIM WITH HIGHER VELOCITY IN MICROGRAVITY 4HIS INCREASED VELOCITY IS COUPLED TO CHANGES IN PHOSPHORILIZATION OF SPECIʄC ʅAGELLAR PROTEINS ;4ASHAND"RACHO =!LTEREDGRAVITYCHANGESMAMMALIANMALEANDFEMALEREPRO DUCTIVESYSTEMSINARATHERCOMPLEXMANNER&OREXAMPLE ATRANSIENTBUTDRAMATIC REDUCTION IN TESTIS WEIGHT AND TESTOSTERONE HAS BEEN REPORTED IN MALE RATS IN ORBIT (OWEVER THE PITUITARY RESPONDED IN A PHYSIOLOGICAL MANNER TO CHANGES IN PLASMA TESTOSTERONE INDICATINGTHATTHEHYPOTHALAMIC PITUITARY GONADALAXISWASNOTIMPAIRED

3PACE"IOLOGY



BYSPACEʅIGHT3O SPERMATOGENESISWASNOTREDUCED%XAMINATIONOFTHEOVARIESOF POSTPARTUM RATS ʅOWN IN SPACE DURING ǻ DAYS OF GESTATION SHOWED NO EFFECT ON OVARIANWEIGHTORNUMBERFOLLICLES;4OUETAL =4HEPHYSIOLOGICALMECHANISMS FORREPRODUCTIONAREOBVIOUSLYINTACTINMICROGRAVITY DESPITEOFMODIʄCATIONSOFSOME COMPONENTSOFTHECOMPLETESYSTEM !SFORTHEEARLYPERIODOFDEVELOPMENT THEEFFECTSOFMICROGRAVITYONNERVOUS SYSTEMDEVELOPMENTWERECONSIDEREDINONLYAFEWANIMALSPECIESANDSPECIʄCTRACTS 7HILETHESEEFFECTSONTHEEARLYFORMATIONOFTHENERVOUSSYSTEMWEREMAINLYBASED ONSTUDIESINTHEAQUATICANIMALS AXONALGROWTHANDDENDRITICMORPHOLOGYRELATEDTO FUNCTIONSSUCHASEQUILIBRIUMCONTROLANDCONTROLOFCIRCADIANACTIVITY RESPECTIVELY WEREALSOSTUDIEDINRATS 2ATEMBRYOSEXPOSEDTOMICROGRAVITYDURINGTHEPERIODWHENTHEVESTIBULARSYS TEMSTARTSTOBECOMEFUNCTIONAL SHOWEDDELAYEDDEVELOPMENTCOMPAREDTOCONTROLS )N PARTICULAR  H AFTER SHUTTLE LANDING CENTRAL PROJECTIONS FROM THE GRAVISENSING ORGANS RECEPTORS TO THE MEDIAL VESTIBULAR NUCLEUS WERE MORE IMMATURE THAN IN THE CONTROLS;"RUCE =4HISRESULTSUGGESTSTHATGRAVITYISREQUIREDFORAPPROPRIATE SYNAPTIC DEVELOPMENT AND ʄNE TUNING OF THE PROJECTIONS FROM THE GRAVITY SENSING RECEPTORSTOTHECENTRALNERVOUSSYSTEM4HESEOBSERVATIONSWERESUPPLEMENTEDBY STUDIESOFNEONATERATSDURINGTHE DAY.EUROLAB343 MISSION WHICHREVEALED ANABSENCEOFCONNECTIONSINTOTHEVESTIBULARNUCLEIFROMTHECEREBELLUM THEMAIN CONTROL CENTER FOR BALANCE AND COORDINATION OF MOVEMENT ;2AYMOND ET AL = 2ECENTSTUDIESHAVEALSOREVEALEDTHATMICROGRAVITYAFFECTEDTHERETINASOFNEONATAL RATS PROBABLYBYDEGENERATIONOFCELLSORPARTSOFINDIVIDUALCELLTYPES;4OMBRAIN 4INKAND"ARNSTABLE = 4HEFORCEOFGRAVITYMAYINʅUENCEEVENTSUNDERLYINGTHEPOSTNATALDEVELOPMENT OFMOTORFUNCTIONINRATS SIMILARTOTHOSENOTEDINHATCHLINGQUAIL3UCHEFFECTSMOST LIKELYDEPENDONTHEAGEOFTHEANIMAL DURATIONOFTHEALTEREDGRAVITATIONALLOADING ANDTHESPECIʄCMOTORFUNCTION4HEEFFECTOFMICROGRAVITYONMUSCLEMASSANDFUNC TION OCCURS IN LESS THAN  WEEK ;4ISCHLER ET AL = 4HE OSSIʄCATION OF SKELETAL BONESOFFETUSESOFFEMALERATSʅOWNINSPACEDURINGTHEIRPREGNANCYWASARRESTED (OWEVER DURINGTHE GRE ADAPTATIONPERIOD THEREDUCEDOSSIʄCATIONOFTHEEMBRYOS WASOVER COMPENSATED ANDNEWBORNSFROMTHISMISSIONWEREAHEADOFTHECONTROLS %XPOSUREOFBONEANDBONECELLCULTURESORIGINATINGFROMMAMMALSTOMICROGRAVITYIS AWIDELYUSEDTOOLFORUNDERSTANDINGTHEUNDERLYINGMECHANISMSOFBONEFORMATION .EVERTHELESS THE BASIC MECHANISMS OF THE MODIʄCATIONS IN DEVELOPING BONES IN MICROGRAVITYAREPOORLYUNDERSTOOD)SOLATEDFETALMOUSELONGBONESEXPERIENCENO CHANGE IN RELATIVE LENGTH INCREASE AND COLLAGEN SYNTHESIS INDUCED BY MICROGRAVITY )NSTEAD ADECREASEDMINERALIZATION ASWELLASADECREASEINGLUCOSECONSUMPTIONAND ANINCREASEINCALCIUMRELEASEISSEEN;6AN,OONETAL = ,IKEMORPHOLOGY ALLPHYSIOLOGICALFUNCTIONSINORGANISMS ASWELLASTHEIRBEHAV IOR EXPERIENCE MODIʄCATIONS DURING DEVELOPMENT 4HE RIGHTING RESPONSE FROM A SUPINEPOSTURETOAPRONEPOSTUREISAGOODEXPERIMENTALMODELTOTESTMATURATIONOF VESTIBULARFUNCTION"ESIDETHEVESTIBULARSYSTEM TACTILECUESFROMCONTACTWITHASOLID SURFACE ASWELLASPROPRIOCEPTIVECUESFROMMUSCLESPINDLESANDTENDONSCONTRIBUTETO ASUCCESSFULRIGHTINGRESPONSE4OSEPARATETHECONTRIBUTIONOFVESTIBULARFROMOTHER SENSORYINPUTS THERIGHTINGRESPONSECANBESTUDIEDDURINGWATERIMMERSION IE THE



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Figure 2.18. This Cartoon Shows the Sequence of Body Movements During the Righting Response in Water by Neonatal Rats Raised on Earth (Synchronous) or Exposed to Microgravity (Flight). (Credit Philippe Tauzin).

ANIMALISPOSITIONEDINTHESUPINEPOSITIONINAWATER ʄLLEDCONTAINERANDTHENRELEASED 2IGHTING BEHAVIOR IN THE ABSENCE OF TACTILE CUES REVEALED CLEAR RESPONSE DEʄCITS IN NEONATES THAT UNDERWENT PRENATAL DEVELOPMENT IN SPACE &IGURE   %XPOSURE TO MICROGRAVITYDURINGPOSTNATALPERIODSOFLIFESIGNIʄCANTLYRETARDEDTHEDEVELOPMENTOF THISRIGHTINGBEHAVIOR;2ONCA = 7ALTON;=ALSOREPORTEDDIFFERENCESINSWIMMINGBEHAVIORANDLOCOMOTIONIN NEONATALRATSWHENTHEMUSCULO SKELETALSYSTEMDIDNOTBEARWEIGHTDURINGCRITICAL TIMESOFDEVELOPMENT4HERESULTSFROMTHE DAY.EUROLABSHUTTLEMISSIONSHOWED THATNEONATALRATSʅOWNINSPACEEXHIBITEDALTEREDLOCOMOTORBEHAVIORALDEVELOPMENT THATPERSISTEDFORTHE MONTHRECOVERYPERIOD ANDTHATRIGHTINGREʅEXSTRATEGIESWERE STILLABNORMALMONTHSAFTERRETURNTO%ARTH /NEINTERESTINGFEATUREOFSENSORY NEURONAL ANDMOTORSYSTEMSISTHEEXISTENCEOF CRITICALPERIODSDURINGTHEIRDEVELOPMENT4HECONCEPTOFCRITICALPERIODDURINGDEVEL OPMENTGOESBACKTOSTUDIESPERFORMEDBY.OBELPRIZESLAUREATES(UBELAND7IESEL ;=ONTHEVISUALSYSTEMINKITTEN$EPRIVATIONISTHEPREFERREDSCIENTIʄCMETHODTO STUDYTHEEXISTENCEANDDURATIONOFCRITICALPERIODS#ONSEQUENTLY EVERYLONG LASTING CHANGEINTHEENVIRONMENTMAYHAVEITSSPECIʄCCRITICALPERIOD)NGENERAL THREECRI TERIAMUSTBEFULʄLLEDTODEʄNEADEVELOPMENTPERIODASȃCRITICALȄA THEDEVELOPING SYSTEMMUSTBESUSCEPTIBLETOASPECIʄCENVIRONMENTALMODIʄCATIONB THEEXTENTOF MODIʄCATIONMUSTBERELATEDTOAGE ANDINPARTICULARTOAWELL DEʄNEDPERIODOFDEVEL OPMENTANDC THEMODIʄCATIONMUSTPERSISTFORLONGPERIODSOFPOSTNATALLIFEOREVEN PERMANENTLY)NSPACESTUDIES ONLYTHEʄRSTTWOCRITERIAWEREOBSERVEDINDEED LONG DURATIONEFFECTSOFIRREVERSIBILITYWERERARELYNOTED /THERRESULTSFROMSPACESTUDIESINDICATEDDELAYEDDEVELOPMENTOFCERTAINNERVE CONNECTIONSTOMUSCLES4HECONNECTIONSRETURNEDTONORMALAFTERRETURNTO%ARTH YET

3PACE"IOLOGY



ʄBERS IN HIND LIMB MUSCLES DID NOT REACH NORMAL SIZE EVEN AFTER A MONTH BACK ON %ARTH4HEDATASUGGESTTHATBIOMECHANICALLOADINGOFLIMBSDURINGEARLYDEVELOPMENT MAYBEESSENTIALFORINNERVATIONOFMUSCLES!NOTHERMECHANISM HOWEVER MAYBEAT WORKBESIDESTHELACKOFLOADINGDURINGCRITICALTIMES THEREISALSOTHEPOSSIBILITYTHAT ADAPTIVE CHANGES IN THE VESTIBULAR SYSTEM PARTICULARLY THE REDUCTION IN DESCENDING OTOLITH INPUT REQUIRED TO MAINTAIN MUSCLE TONE SEE ( REʅEX DATA IN #HAPTER  3ECTION MODIFYTHENERVE TO MUSCLECONNECTIONS;2ONCAAND!LBERTS = 4ODATE RELATIVELYLITTLENEUROBEHAVIORALRESEARCHHASBEENDONEINMICROGRAVITY WITHVERTEBRATES JUVENILEORADULT4HISISPARTLYBECAUSETHEHABITATSFORRAISINGTHEM IN SPACE DID NOT EXIST AND BECAUSE THE STUDY OF VERTEBRATES UP TO SEXUAL MATURITY REQUIRESLONGEREXPOSURETOMICROGRAVITY;7ASSERSUG =4HE)33WILLNOWPRO VIDEBOTHCAPABILITIES0HYSIOLOGICALEXPERIMENTSUSINGIMPLANTEDELECTRODESINʄSH RATS ORRHESUSMONKEYSHAVEPROVIDEDINTERESTINGDATAONTHEADAPTIVECHANGESINTHE NEURO VESTIBULARSYSTEM FOREXAMPLESEE#HAPTER 3ECTION (OWEVERTHESE EXPERIMENTS ARE LIMITED TO CONSTRAINED OR CAGED ANIMALS WHICH DO NOT EXPERIENCE MOTIONINMICROGRAVITY MAKINGITDIFʄCULTTODRAWACOMPARISONWITHADAPTIVECHANGES INASTRONAUTS4HERESPONSEOFANIMALSTOFREE FALLISASTONISHINGLYDIVERSE ASSHOWN BYTHEOBSERVATIONSMADEONFROGS LIZARDS ANDSNAKESINPARABOLICʅIGHT;7ASSERSUG =/THEROBSERVATIONSOFANIMALSPLACEDINMICROGRAVITYAFTERVESTIBULARLESIONS PROVEINTERESTINGFORUNDERSTANDINGTHEROLEOFGRAVITYINTHEPROCESSOFRECOVERYOF BALANCEFUNCTION )NCONCLUSION SHORT DURATIONEXPOSURETOTHESPACEENVIRONMENTDOESNOTSIGNIʄ CANTLY AFFECT THE EMBRYONIC DEVELOPMENT ALTHOUGH INTERESTING AND UNEXPLAINED CHANGESOCCURDURINGEMBRYOGENESISANDEARLYDEVELOPMENT(OWEVER BECAUSETHE ANIMALSINMOSTOFTHESESTUDIESWEREONLYPARTIALLYADAPTEDTOTHESPACEENVIRONMENT DUETOTHESHORTDURATIONOFTHEʅIGHT ITISPOSSIBLETHATLONG DURATIONEXPOSUREWILL HAVEMORESIGNIʄCANTEFFECTS4HEOPPORTUNITYTOCONDUCTDEVELOPMENTSTUDIESONBOARD THE)33WILLLEAVEROOMFORMUCHINVESTIGATION

 0LANTBIOLOGY  1UESTIONS /N%ARTH PLANTROOTSASARULEGROWDOWNWARDTOWARDGRAVITY WHILESTEMSGROWUP AND AWAY FROM GRAVITY A PHENOMENON KNOWN AS GRAVITROPISM SEE &IGURE   #IRCUMNUTATION IE THESUCCESSIVEBOWINGORBENDINGINDIFFERENTDIRECTIONSOFTHE GROWING TIP OF THE STEMS AND ROOTS MIGHT ALSO DUE IN PART TO GRAVITY "Y STUDYING PLANTSINMICROGRAVITYONBOARDSPACECRAFT BIOLOGISTSSEEKTOUNDERSTANDHOWPLANTS RESPOND TO GRAVITY AT MICROSCOPIC AND MACROSCOPIC LEVELS !LSO PLANTS RESPOND TO ENVIRONMENTAL STIMULI SUCH AS LIGHT TEMPERATURE AND MAGNETIC OR ELECTRIC ʄELDS 4HESERESPONSESAREMASKEDON%ARTHBYTHEOVERRIDINGRESPONSEOFPLANTSTOGRAVITY )N ADDITION ANY EXPLORATION STRATEGY THAT INCLUDES A LONG TERM SUSTAINED HUMAN PRESENCEINSPACEABSOLUTELYREQUIRESTHEABILITYTOCONTINUOUSLYGROWANDREPRODUCE VARIOUS PLANT SPECIES OVER MULTIPLE GENERATIONS FOR FOOD PRODUCTION AND CLOSED ENVIRONMENTALLIFESUPPORTSYSTEM



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 2ESULTSOFSPACEEXPERIMENTS ! LARGE VARIETY OF PLANTS WITH SHORT LIFE SPANS HAVE ʅOWN IN SPACE ALGAE CARROTS ANISE PEPPER WHEAT PINE OAT MUNG BEANS CRESS LENTILS CORN SOYBEANS LETTUCE CUCUMBERS MAIZE SUNʅOWERS PEAS COTTON ONION NUTMEG BARLEY SPINDLETREES ʅAX ORCHIDS GLADIOLAS DAYLILIES ANDTOBACCO"ECAUSEOFTHISWIDEVARIETY FORTHEMOST PART OBSERVATIONSONPLANTSEXPOSEDTOMICROGRAVITYHAVEBEENANECDOTAL)THASBEEN DEMONSTRATEDREPEATEDLYTHATPLANTSDOGROWINMICROGRAVITY(OWEVER WHETHERPLANTS CANGROWANDDEVELOPNORMALLYOVERSEVERALGENERATIONSREMAINSTOBEDETERMINED  'RAVICEPTION &ORRESEARCHPURPOSES THEGRAVITATIONALRESPONSE ASWITHANYSTIMULUSRESPONSE HAS BEEN DIVIDED INTO THREE STEPS A STIMULUS PERCEPTION HOW A PLANT SENSES GRAVITY B SIGNALTRANSDUCTIONHOWTHEPLANTTRANSFERSTHISKNOWLEDGEINTOACTIONANDC THE RESPONSE OR RESULTING ACTION DIFFERENTIAL CELL ELONGATION OR DIFFERENTIAL GROWTH THAT RESULTSINTHEROOTORSHOOTBENDINGINANEWDIRECTION 7HERE DOES THE RESPONSE OCCUR )N ROOTS WE HAVE ALREADY SEEN THAT PERCEPTION OCCURSINTHEROOTCAPSEE&IGURESAND 4HESENSINGMECHANISMUNDERLYINGA PLANTȀSABILITYTOORIENTITSORGANSINAGRAVITATIONALʄELDSEEMSTOINVOLVETHESEDIMEN TATION OF INTRACELLULAR PARTICLES KNOWN AS STATOLITHS 4HE STATOLITHS EACH CONSIST OF A NUMBEROFSTARCHGRAINSSURROUNDEDBYTWOMEMBRANES THESTRUCTUREBEINGTERMEDAN AMYLOPLAST7ITHTHEMOVEMENTOFSTATOLITHS THECELLRECEIVESAMECHANICALSTIMULUS (OWACELLTRANSFERSTHISMECHANICALSTIMULUSINTOACHEMICALSIGNALISSTILLOFGREAT DEBATE/NEHYPOTHESISISTHATASTHESTATOLITHSȃFALLȄ THEYCOMETORESTONOTHERORGAN ELLESSUCHASTHEENDOPLASMICRETICULUMORPLASMAMEMBRANE THUSEXERTINGPRESSURE ONTHEORGANELLETHATRESULTSINTHEOPENINGOFIONCHANNELSANDTHERELEASEOFIONSSUCH ASCALCIUMTHATINITIATETHESIGNALTRANSDUCTIONPATHWAY;0ERBALETAL = 4RANSMISSIONOFTHESTIMULUSTOTHEREACTIONZONE IE THEBENDINGOFTHEROOT COULDOCCURBECAUSEOFACHANGEINTHEʅOWOFTHEPLANTHORMONEAUXIN(OWGRAVITY REGULATESAUXINTRANSPORTREMAINSUNKNOWN.EVERTHELESS AUXINTYPICALLYʅOWSINA ʄXEDDIRECTION FROMTHESHOOTTOWARDSTHEROOT!FTERʅOWINGDOWNTOTHEROOTTIPS AUXINBEGINSTOʅOWINTHEOPPOSITEDIRECTION ASIFMAKINGA5 TURN ALONGTHEROOTS )FTHEROOTISTILTEDRELATIVETOGRAVITY THECONCENTRATIONOFAUXININCREASESINTHELOWER PARTOFTHEELONGATIONZONEINTHEROOT CAUSINGADIFFERENTIALGROWTHBETWEENTHELOWER PARTANDTHEUPPERPART!SARESULT THEROOTBENDSDOWNWARD&IGURE  )NMICROGRAVITY STATOLITHSDONOTSETTLEWITHINTHEROOTCAPCELLS&IGURE SO GRAVITYISNOTPERCEIVED NORISASYMMETRICAUXINDISTRIBUTIONINDUCED-ICROGRAVITY EXPERIMENTSONBOARDSOUNDINGROCKETS THESPACESHUTTLE ANDTHE)33HAVESHOWN THATGROWTHDIRECTIONWASINDEEDUNCONTROLLEDINMICROGRAVITY ANDSOMEROOTSEVEN EXTENDEDINTHESAMEDIRECTIONASTHEAERIALSTEMS&IGURE  /NBOARDCENTRIFUGEEXPERIMENTSHAVEDEMONSTRATEDTHATSEEDLINGSGROWNINSPACE REQUIREDADOSEOFǻGSGRAVITYTIMESECONDS ORLESSTHANGFORǻS

)NTERESTINGLY PHOTOTROPISMINSHOOTSSEEMSTOOBEYTOTHESAMEMECHANISM,IGHTWOULDSTIMULATETHE MOVEMENTOFAUXINAWAYFROMTHELIGHTSOURCE4HEINCREASEDSUPPLYOFAUXINTOCELLSOPPOSITETHELIGHT SOURCEWOULDCAUSETHEMTOELONGATEMORETHANTHECELLSONTHESAMESIDEASTHELIGHTSOURCE



3PACE"IOLOGY



Figure 2.19. The Different Phases of the Gravitropic Curvature of the Root.&OUR0HASES Are Generally Distinguished. The Perception Is the Physical Phase of the Gravitropic Reaction and Corresponds to the Movement of the Statoliths in the Gravisensing #ELLS,OCATEDINTHE2OOT#AP)T)S&OLLOWEDBYTHE4RANSDUCTIONOFTHE3TIMULUS i.e., the Transformation of the Mechanical Effect of Gravity into a Biochemical &ACTOR "OTH 0HASES /CCUR 7ITHIN THE 'RAVISENSING #ELLS 4HE 4RANSMISSION OF 'RAVISTIMULUS TO THE 2EACTION :ONE #ONSISTS IN AN !SYMMETRICAL (ORMONAL -ESSAGE$OWNWARD4RANSPORTOF!UXIN )T)S2ESPONSIBLEFORA$IFFERENTIAL'ROWTH #URVATURE THAT/CCURS&AR!WAYFROMTHE0ERCEPTION:ONE.OTETHE4IME3CALE (Credit Philippe Tauzin).

Figure 2.20. Comparison of the Position of the Statoliths in Roots Grown in the Vertical Position (1 G), in Microgravity (0 G) or on a Clinostat. The Limits of the Protoplasm, the Statoliths, and the Nucleus Are Represented. (Adapted from Smith ETAL;]. Credit Philippe Tauzin).

Figure 2.21. Photographs of Rice and Arabidopsis Seeds Cultivated on Earth and in Microgravity.#REDIT4AKAYUKI(OSON /SAKA#ITY5NIVERSITY 



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TOELICITAGRAVITROPICROOTBENDING RESPONSE;0ERBALAND$RISS %COLE =3TUDIES HADREVEALEDTHATTHEMINIMUMFORCETHATISSENSEDBYPLANTORGANSISINTHERANGEOF ”ȪGFORROOTSANDȪGFORSHOOTS;3HEN -ILLERETAL = BUTTHESEVALUES WEREOBTAINEDONCLINOSTATSWITHABACKGROUNDOFG4HESETHRESHOLDSHAVENOTBEEN CONʄRMEDINSPACESTUDIESYET ASTHELOWESTGLEVELGENERATEDBYONBOARDCENTRIFUGES ISG IE TIMESMORETHATTHESUPPOSEDTHRESHOLDACCELERATIONOF”ȪG (OWEVER IN ʅIGHTEXPERIMENTSINDICATEDTHATTHEROOTISABLETOPERCEIVEITSORIENTA TIONWITHRESPECTTOALINEARACCELERATIONVECTORANDTOGENERATEASIGNALOFCURVATURE INLESSTHANS !NOTHERINTERESTINGOBSERVATIONISTHEFACTTHATTHESTATOLITHSAREMORESENSITIVEIN  GGROWNPLANTSTHANPLANTSGROWNIN G;0ERBALETAL =)NMICROGRAVITY THE AMYLOPLASTSARESITUATEDNEARTHENUCLEUS WHEREASINGTHEYARESEDIMENTEDONTHE ENDOPLASMICRETICULUM7HENACENTRIFUGALFORCEISAPPLIEDTOTHEORGANS THEPROB ABILITYOFHAVINGCONTACTSBETWEENAMYLOPLASTSANDTHERETICULUMTUBULESISMUCH LESS IN  G THAN IN  G ALTHOUGH THE RESPONSE IS GREATER IN  G THAN IN  G 4HUS EXPERIMENTSPERFORMEDINSPACEBROUGHTASTRONGARGUMENTAGAINSTTHEHYPOTHESIS BASEDONAROLEOFTHEENDOPLASMICRETICULUMINTHETRANSDUCTIONOFGRAVITYSTIMULUS ;0ERBAL = 4O SOME EXTEND THE TRANSDUCTION PATHWAY OF THE GRAVITY SENSING MECHANISMS COULDBEANALYZEDINSPACEBYUSINGTRANSGENICPLANTS/NEEXPERIMENTCURRENTLYON GOINGONBOARDTHE)33EXAMINESCALCIUMREDISTRIBUTIONIN!RABIDOPSISPLANTSHARBOR INGADEPLETIONOFAUXININSOMEAREAS %VENON%ARTH THESHOOTAPEXOFAPLANTMAYNOTGROWDIRECTLYUPWARDS BUTIT MAYEXHIBITCONTINUOUSHELICALANDSPIRALMOVEMENTSASITGROWSSOTHATSEENFROMTHE SIDEITAPPEARSTOOSCILLATE4HISCIRCUMNUTATIONMOVEMENTMAYBEACONSTANTSEEKING OFTHEAPEXFORPERFECTALIGNMENTALONGTHELINEOFTHEGRAVITATIONALFORCEANDBEDETER MINED BY CONSTANT ADJUSTMENTS IN THE LEVELS OF HORMONES PRODUCED IN RESPONSE TO GRAVITYPERCEPTION%XPERIMENTSUSINGSUNʅOWERSEEDLINGS ǻDAYSOLD GROWNIN SPACE REVEALED THAT CIRCUMNUTATION TAKES PLACE IN MICROGRAVITY ALBEIT WITH SOME REDUCTIONINTHEAMPLITUDEOFOSCILLATION INDICATINGTHATGRAVITYISNOTESSENTIAL;"ROWN ETAL = 0EGFORMATIONONCUCUMBERS MELONS ANDSQUASHISALSOINʅUENCEDBYGRAVITY ! PEG IS A SMALL PROTUBERANCE THAT DEVELOPS IMMEDIATELY AFTER GERMINATION IN THE TRANSITION ZONE BETWEEN ROOT AND STEM WHICH HELPS THE CUCURBITACEOUS SEEDLINGS SHED THEIR SEED COATS /N %ARTH THE DOWNWARD GROWTH GRAVITROPISM OF THE ROOTS RESULTSINACURVATUREATTHETRANSITIONZONE7HENSEEDSGERMINATEINAHORIZONTALOR INCLINEDPOSITION APEGDEVELOPSONTHELOWER CONCAVESIDEOFTHEBENDINGTRANSITION ZONEATANEARLYSTAGEOFSEEDLINGGROWTH!SSUCH ITHADBEENPRESUMEDTHATPEG FORMATIONWASREGULATEDBYGRAVITY)TWASRECENTLYDISCOVEREDTHATWHENCUCUMBER SEEDSGERMINATEINSPACE APEGFORMSONEACHSIDEOFTHETRANSITIONZONE INDICATING THATPEGSDEVELOPWITHORWITHOUTGRAVITY(OWEVER ON%ARTH THESEEDLINGSSUPPRESS PEGFORMATIONONTHEUPPERSIDEOFTHEINCLINEDTRANSITIONZONEINRESPONSETOGRAVITY WHICHCAUSESUNILATERALPLACEMENTOFTHEPEGINCUCUMBERSEEDLINGS BUTINSPACETHE SECONDPEGREMAINS;4AKAHASHIETAL =%XPERIMENTSARECURRENTLYBEINGCON DUCTEDONBOARDTHE)33TOINVESTIGATETHECONSEQUENCESOFTHEPRESENCEOFMOREPEGS ONTHEPLANT

3PACE"IOLOGY



 $EVELOPMENTOFPLANTS 4HEQUESTIONSRAISEDBYGROWINGPLANTSINTHESPACEENVIRONMENTARETHEFOLLOWING (OWWILLSPACEAFFECTSEEDVIABILITYANDGERMINATION)SPLANTDEVELOPMENTNORMALIN SPACE7ILLPLANTSBEABLETOREPRODUCEINSPACE3IGNIʄCANTLY RESULTSOFSTUDIESON THE'ERMAN3PACELAB $MISSION WHICHINCORPORATEDONBOARD GCENTRIFUGECON TROLS INDICATEDTHATSINGLEPLANTCELLSBEHAVENORMALLYOREVENEXHIBITEDACCELERATED DEVELOPMENT )N CONTRAST THE ROOTS OF SEEDLINGS GERMINATED IN MICROGRAVITY GREW STRAIGHTOUTFROMTHESEED ANDTHESAMEROOTSCONTAINEDSTATOLITHSTHATWEREMOREOR LESSRANDOMLYDISTRIBUTEDINTHEIRCELLS#ONTROLROOTSCENTRIFUGEDATGIN ʅIGHT WERE NORMALLYGRAVITROPIC&IGURE  -ANY SPECIES OF PLANTS HAVE GROWN IN MICROGRAVITY )N  THE ʄRST PLANT !RABIDOPSIS THALIANA WAS SUCCESSFULLY GROWN FROM SEED TO ʅOWERING PLANT AND TO NEXTGENERATIONOFSEEDSON 3ALYUT 4HISWASREPEATEDFORTHEʄRSTPOTENTIALCROP PLANT SUPERDWARFWHEAT ON-IRIN)TAPPEARSTHATTHEABSENCEOFGRAVITYHASNO REALEFFECTONGERMINATION&OREXAMPLE MILLIONTOMATOSEEDSREMAINEDINSPACE FORYEARS ASPARTOFANEXPERIMENTEMBARKEDONTHE,ONG$URATION%XPOSURE&ACILITY ,$%& ASATELLITETHESIZEOFASCHOOLBUSTHATWASPLACEDINORBITBYTHESPACESHUTTLE ANDRETRIEVEDBYANOTHERCREWYEARSLATER0OSTʅIGHTMEASUREMENTOFGERMINATION SHOWED NO DIFFERENCE WITH GROUND CONTROLS INDICATING THAT SEEDS REMAIN VIABLE IN SPACE #YTOLOGICAL STUDIES OF ROOTS ʅOWN UNDER A VARIETY OF CONDITIONS IN SPACE HAVE CONSISTENTLY REVEALED REDUCED CELL DIVISIONS AS WELL AS A VARIETY OF CHROMOSOMAL ABNORMALITIES 2EDUCED AMOUNTS OF CELLULOSE AND LIGNIN WERE ALSO FOUND IN SPACE GROWNMUNGBEAN OAT ANDPINE%ARLYSPACEEXPERIMENTSEXHIBITEDPOORPLANTGROWTH

Figure 2.22. Experiments Carried Out on the German Spacelab-D1 Mission Showing that Roots May Grow Randomly in Microgravity (a), But Can be Reoriented Uniformly on Exposure to 1 g on a Centrifuge (b, c) for as little as 3 h. (Adapted FROM-C,AREN;]. Credit Philippe Tauzin).



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ANDALTEREDDEVELOPMENTPLANTSDIEDINTRANSITIONFROMVEGETATIVETOʅOWERINGSTAGE ORPLANTSʅOWERED BUTWEREABNORMAL"EGINNINGIN ASERIESOFEXPERIMENTSON THESPACESHUTTLEANDTHENON-IRWASINITIATEDTOEXAMINETHISPROBLEM)TNOWAPPEARS THATEARLYABNORMALITIESINPLANTREPRODUCTIONCOULDBECAUSEDBYTHETOXICEFFECTOF ETHYLENE RATHERTHANSPACEʅIGHTFACTORS ANDTHATSEEDSIZEWASDIMINISHEDPOSSIBLY BECAUSE STORAGE AND UTILIZATION OF RESERVES ARE MODIʄED IN ABSENCE OF GRAVITY ;-USGRAVEETAL = !RABIDOPSISTHALIANAHASBEENSUCCESSFULLYGROWNFROMSEED TO SEEDON)33SEE &IGURE $URINGA MONTHGROWTHPERIOD THEPLANTSPROGRESSEDFROMSEEDHYDRA TION TO GERMINATION VEGETATIVE AND REPRODUCTIVE STAGES PRODUCING MATURE SEEDS .INETYPERCENTOFTHESEEDSGERMINATEDINSPACE ALTHOUGHONLYOFTHEPLANTSGREW TOMATURITY3OMEOFTHESEEDSTHATWEREHARVESTEDFROMTHEPLANTSTHATWEREGROWNIN MICROGRAVITY WERE PLANTED IN A GROUND STUDY 4HESE SEEDS PRODUCED TYPICAL PLANTS WITHOUTANYVISIBLEABNORMALITIES;,INKETAL =3OYBEANSWEREALSOGROWNFROM SEEDTOSEEDFORTHEʄRSTTIMEINSPACE"IOMASSPRODUCTIONINTHESPACESEEDSWAS APPROXIMATELYLARGERTHANGROUNDCONTROLS&LIGHTANDGROUNDSCONTROLSPRODUCED NEARLY IDENTICAL NUMBERS OF SEEDS BUT THE SPACE SEEDS WERE LARGER ON AVERAGE 3CIENTISTSFOUNDTHATTHESEEDSTHATWEREPRODUCEDINSPACEWEREHEALTHY THEGERMINA TIONRATESWERECOMPARABLETOTHOSEON%ARTH ANDNOMAJORMORPHOLOGICALDIFFERENCES WEREEVIDENT "RASSICARAPAʄELDMUSTARD AND4RITICUMAESTIVUMSUPERDWARFWHEAT PLANTS WEREGERMINATEDANDGROWNINAPLANTGROWTHCHAMBEROVERSEVERALGROWTHCYCLESON )33"YTHEENDOFTHEEXPERIMENT THEPLANTGROWTHCHAMBERPRODUCEDATOTALOFEIGHT HARVESTS SEVENPRIMINGS ANDAPLANTTISSUEARCHIVEOFMORETHANPLANTS)N ʅIGHT PROGRESSOFPLANTGROWTHISMONITOREDTHROUGHIMAGECOLLECTIONHARVESTEDPLANTSARE FROZENORʄXEDFORLATERANALYSISONTHEGROUND;-ORROWETAL =3EEDPROTEIN WASSIGNIʄCANTLYLOWERINTHE)33MATERIAL!LSO MICROSCOPYOFIMMATURESEEDSʄXED ON)33SHOWEDEMBRYOSTOBEATARANGEOFDEVELOPMENTALSTAGES WHILEGROUNDCON TROLEMBRYOSHADALLREACHEDTHESAMESTAGEOFDEVELOPMENT4HESEDIFFERENCESCOULD BEATTRIBUTABLETODIFFERENCESINWATERDELIVERYORREDUCEDGASEXCHANGEDUETOLACKOF CONVECTION&IGURE  0LANTSCONTINUETOCONDUCTPHOTOSYNTHESISANDTRANSPIRATIONINSPACE(OWEVER SOMESTUDIESINDICATEADECREASEDABILITYTODOSO#HLOROPLASTSCANHAVETHEIRINTERNAL STRUCTURE DISORGANIZED AND THEIR STARCH STORES DEPLETED 7HEN PLANTS WERE ABLE TO PRODUCESEEDSINSPACE EITHERADDITIONALLIGHTWASNEEDEDVERSUSON%ARTHORITWAS NOTEDTHATOXYGENPRODUCTIONFROMPHOTOSYNTHESISWASREDUCED4HESERESULTSSUGGEST THAT THE MICROGRAVITY ENVIRONMENT MAY AFFECT THE ʅAVOR AND NUTRITIONAL QUALITY OF PRODUCESGROWNINSPACE;-USGRAVEETAL = 4HEGROWTHANDDEVELOPMENTOFTHEDWARFWHEATPLANTSONTHE)33WASSIMILARTO THEGROWTHANDDEVELOPMENTOFPLANTSON%ARTH!NALYSISOFTHEPLANTSINDICATEDTHAT THEMICROGRAVITY GROWNPLANTSWERETALLERTHANPLANTSGROWNON%ARTH)NG BY COMPARISONWITH GCONTROL THEGROWTHOFTHEPRIMARYROOTANDITSAPICALUP DOWN DOMINANCEOVERTHESECONDARYROOTSWEREREDUCED&IGURE !LSO THEGROWTHOF PLANTORGANSINSPACESEEMSCHARACTERIZEDBYCHANGESINTHEORIENTATIONOFSTEMAND LEAVESANDSECONDARYROOTS MOREADVENTITIOUSROOTS ANDFASTERGROWTHOFSECONDARY ROOTS4HEMORPHOLOGYOFTHEPRIMARYROOTISNOTSTRONGLYMODIʄED%XPERIMENTSIN

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Figure 2.23. Astronaut Peggy A. Whitson Displays a First Crop of Soybeans Growing Inside the Advanced Astro-Culture Unit on Board the ISS. 4HIS%XPERIMENT)S5SEDTO $ETERMINE/PTIMAL4IMEFOR#ROSS 0OLLINATIONAND(ARVESTING#REDIT.!3! 

Figure 2.24. Summary of the Effects of Microgravity on the Development and Growth of Plant Roots and Shoots.!DAPTEDFROM0ERBAL;200]).

SPACE SHOULD BE DONE TO CONʄRM THAT THE REDUCED APICAL DOMINANCE RESULTS FROM A CHANGEINTHEHORMONALCONTENTINROOTS/NCEAGAIN!RABIDOPSISHARBORINGAGENE RESPONSIBLEFORAUXINDEPLETIONWILLBEUSEFULTOANALYZEAUXINDISTRIBUTIONINSPACE GROWNSEEDLINGS



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4HECELLCYCLEHASBEENINTENSIVELYSTUDIEDINPLANTSINTHELASTDECADE;)NZ¦ = 0LANTMOLECULARBIOLOGISTSNOWHAVETHEOPPORTUNITYTOUSEMANYMOLECULARTOOLSTO ANALYZEPLANTGROWTHINSPACE;0AULAND&ERL =7EARECLOSETOUNDERSTANDINGTHE CAUSESOFTHECHANGESINTHEDEVELOPMENTOFPLANTSINSPACE-ANYPIONEERINGEXPERI MENTS HAVE BEEN DONE IN SPACE WITHOUT MONITORING GAS COMPOSITION TEMPERATURE HUMIDITY SOTHATTHECONCLUSIONOFTHEIRAUTHORSMUSTBEQUESTIONEDSINCEPLANTSARE VERYSENSITIVETOEXTERNALFACTORS-ORECLEAR CUTRESULTSHAVEBEENOBTAINEDONBOARD THE)33 BECAUSEDEDICATEDFACILITIESPROVIDINGONBOARD GCONTROLSANDBETTERCULTURE CONDITIONSHAVEBEENDEVELOPED7EKNOWTHATTHEREPRODUCTIVEPHASEISCOMPLETEIN MICROGRAVITY WHEN THE CULTURE CONDITIONS GAS AND LIQUID EXCHANGES ARE ADEQUATE (OWEVER WHETHERORNOTASEEDLINGGROWINGFROMTHEBEGINNINGINMICROGRAVITYAND ACROSS MULTIPLE GENERATIONS CAN ʅOWER AND PRODUCE NORMAL SEEDS THAT CAN LEAD TO NORMALPLANTSREMAINSAMATTEROFDEBATE4HEEXPERIENCEGAINEDFROMTHEPASTSTUDIES WILLBEUSEFULFORTHEFUTURE

 2ADIATIONBIOLOGY 4HEBROADSPECTRUMOFRADIATIONENCOUNTEREDINSPACEGOESFROMEXTREMEULTRAVIOLET RADIATION 8 RAYS AND HIGH ENERGY PARTICLES SUCH AS ELECTRONS NEUTRONS PROTONS TO HEAVYIONSSUCHASIRON4HISSECTIONWILLBELIMITEDTOADESCRIPTIONOFTHEIONIZING RADIATION ENCOUNTERED IN ,%/ AND ITS BIOLOGICAL EFFECTS AS REVEALED BY THE BIOLOGY EXPERIMENTSPERFORMEDDURINGSPACEMISSIONSTODATE!MORECOMPLETEDESCRIPTIONOF THESPACERADIATIONENVIRONMENTCANBEFOUNDIN%CKART;=4HEISSUESOFRADIATION FROMTHEMEDICALPERSPECTIVEWILLBEDISCUSSEDINGREATERDETAILIN#HAPTER  )ONIZEDRADIATIONINSPACE 4HESOURCESOFRADIATIONDURINGSPACEMISSIONSAREDIVERSE (a) Cosmic radiation includes galactic radiation from supernova explosions as well as radiation of solar origin associated with solar flares (Figure 2.25). The primary galactic radiation present outside the Earth’s atmosphere is composed of about 85% protons (with a hydrogen nucleus), 12% alpha particles (with a helium nucleus), and 1.5% of heavy ion particles with high charge and energy. These high-energy particles interact with the nuclei of the nitrogen and oxygen atoms of the atmosphere, resulting in a highly complex secondary radiation, which irradiates the whole surface of the globe. (b) The solar particle radiation consists of 95% protons. High surface doses may be experienced, but dosage levels rapidly decline with the depth of material penetrated. (c) Space missions that include travel within or through the Van Allen belts also add a third source of radiation. The Van Allen belts consist of protons and electrons trapped by the geomagnetic field. A phenomenon of special importance for missions in LEO is the South Atlantic Anomaly, in which the particles are drawn closer to the Earth than at other regions of the globe due to the asymmetry of the geomagnetic field. (d) Finally, additional radiation is created in high-energy collisions of primary particles with spacecraft materials (Figure 2.26).

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Figure 2.25. The Three Main Sources of Ionizing Radiation in Space. (Credit Philippe Tauzin).

Figure 2.26. This Diagram Illustrates the Secondary Radiation Generated by the Collision of Various High-energy Primary Particles with the Spacecraft Materials. (Credit Philippe Tauzin).

4HEʄRSTEVIDENCEOFTHEEFFECTSOFSPACERADIATIONONHUMANCREWARETHEȃLIGHT ʅASHESȄʄRSTOBSERVEDBY!POLLOAND3KYLABASTRONAUTS$URINGMOSTOFTHE3KYLAB  MISSION THESEʅASHESAVERAGEDHHOWEVER ʅASHESINCREASEDTOHWHENTHE  $URINGTHEDEBRIEʄNGOFTHE!POLLO MISSION 0ETE#ONRADREPORTEDTHEFOLLOWINGȃ7EALLDIDSEETHESE CORONADISCHARGES;ȉ=-OSTOFTHETIMEWESAWTHEM DURINGOURSLEEPPERIODSWHENWEWERELYINGINOUR BUNKS;ȉ=4HEYAPPEAREDASEITHERABRIGHTROUNDʅASHORAPARTICLESTREAKINGRAPIDLYACROSSYOUREYEBALL INALONGTHINILLUMINATEDLINE)COULDDETERMINEWHETHERITWASMYLEFTEYEORMYRIGHTEYETHATDIDITATTHE TIMEȄ!LAN"EANALSOREPORTEDȃ)F)WASTHINKINGABOUTWATCHINGFORTHEM )WOULDSEEONEEVERYMINUTE ORSOMEWHATLESS/NEOFTHEMWOULDBEAʅASH ANDABOUTMINLATERTHEREWOULDBEALINE)TDIDNOT APPEARTOMAKEANYDIFFERENCEWHETHERWEWEREINLUNARORBIT TRANSLUNAR TRANSEARTH ORANYTHINGELSE)FYOU JUSTWANTEDTOLOOKFORTHEM YOUCOULDSEETHEMGOINGBYȄ;'ODWIN =



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3KYLABORBITPASSEDOVERTHECENTEROFTHESO CALLEDȃ3OUTH!TLANTIC!NOMALYȄ4HE ʅASHESAREBELIEVEDTOBEDUETOHIGH ENERGYHEAVYPARTICLESOFCOSMICRAYSANDHAVE BEENREPRODUCEDINHUMANSON%ARTHBYEXPOSURETOHIGH ENERGYIONIZINGPARTICLES 4HREEEXPLANATIONSHAVEBEENPROPOSEDTOEXPLAINTHEPHENOMENONOFLIGHTʅASHES SEENBYCREWMEMBERSA ANEMISSIONOFPHOTONSBYHIGH ENERGYPARTICLESSLOWEDBY ʅUIDINTHEEYE#ERENKOVRADIATION B ALIGHTGENERATEDBYTHESEPARTICLESIONIZING ʅUIDINTHEEYEORC ANARTIʄCIALLIGHTSTIMULUSCAUSEDBYTHESEPARTICLESIMPACTING RETINALSENSORSINTHEEYE;0INSKYETAL =  "IOLOGICALEFFECTSOFRADIATION !LL SPACE AGENCIES AGREE THAT THE EFFECTS OF SPACE RADIATION ESPECIALLY ON THE NON DIVIDINGCELLSOFTHERETINAANDCENTRALNERVOUSSYSTEM MUSTBEASSESSEDBEFORELONG DURATION HUMAN MISSIONS BEYOND %ARTHȀS MAGNETOSPHERE ARE ATTEMPTED (OWEVER MOSTOFTHEBIOLOGICALEFFECTSOFRADIATIONREMAINLARGELYUNKNOWN4HEMECHANISMS OFIONIZINGRADIATIONIMPACTSONCELLSAREEITHERDIRECT WITHPARTICLESIMPACTINGAVITAL TARGET MOLECULE AND DIRECTLY TRANSFERRING THEIR ENERGY OR INDIRECT WITH PARTICLES IMPACTINGOTHERMOLECULESEG WATER TOYIELDLONGER LASTING VERY REACTIVEFREERADI CALSWITHUNPAIREDELECTRON  4HEBIOLOGICALEFFECTSOFPROTONSAREFAIRLYWELLUNDERSTOOD4HROUGHBOMBARD MENTOFSPACECRAFTMATERIAL PROTONSPRODUCENEUTRONS4HESENEUTRONS UPONCOLLIDING WITH A HYDROGEN NUCLEUS LIBERATE THEIR ENERGY "ECAUSE LIVING ORGANISMS CONTAIN MANYHYDROGEN RICHCOMPOUNDS SUCHASPROTEINS FAT ANDWATER THEYAREMOST LIKELYTOBEAFFECTED(OWEVER THEHALF LIFEOFNEUTRONSISONLYMIN AFTERWHICH THEYDECAYNATURALLYTOPROTONSANDELECTRONS%ARLYDOSIMETRYPERFORMEDON3KYLAB AND2USSIANSPACESTATIONSINDICATESTHATTHEʅUXOFNEUTRONSISPROBABLYNOTSIGNIʄ CANT4HEMAJORSPACEHAZARDCOMESFROMTHEHIGHLYCHARGEDENERGETICPARTICLES &ROM GROUND BASED EXPERIENCE SUCH AS RADIOTHERAPY OR NUCLEAR EXPLOSION IT IS KNOWN THAT THE EARLY ACUTE EFFECTS OF RADIATION INCLUDE SKIN EFFECTS BURNS EYE LENS OPACIʄCATION CATARACT GRAYING OF HAIR IMMUNE SYSTEM SUPPRESSION HIGHER RISK OF INFECTION ANDTHELOSSOFNON DIVIDINGCELLS,ATEEFFECTSINCLUDECANCERINBLOOD FORMING ORGANSBONEMARROW THYROID LUNG STOMACH COLON ANDBLADDER ANDGENETICEFFECTS WHICHARISEFROM CELLTRANSFORMATIONCHROMOSOMEABERRATIONSANDTRANSLOCATIONS  !TTHECELLULARLEVEL WHEN$.!STRANDSBREAK NON REJOINEDBREAKSCANLEADTO CELLDEATH WHEREASINCORRECTLYREJOINEDBREAKSCANLEADTOMUTATION4HETEMPORALAND SPATIALCHARACTERISTICSOFTHERADIATIONENERGYDETERMINETHEQUANTITYANDQUALITYOF DAMAGE 3INGLE STRAND BREAKS CAN NORMALLY REPAIR (OWEVER DOUBLE STRAND BREAKS WITHCLOSESINGLEHITSORAHIGH DENSITYENERGYHITDONOTREPAIR#ELLSINMITOSISARETHE MOSTVULNERABLE(IGH ENERGYPARTICLES WITHAHIGHCAPACITYTOTRANSFERTHEIRENERGY ALONGTHEPATH CANGENERATESIGNIʄCANTPERCENTAGEOFDOUBLE STRAND$.!BREAKS4HE EFFECTSAREWIDESPREADANDCANLEADTOTHEDEATHOFNUMEROUSCELLSALONGTHEPATH)N ADDITION ITISDIFʄCULTTOPROTECTTHEVEHICLEANDITSINHABITANTSFROMTHESEPARTICLES EVENWITHSHIELDING;4OBIASAND4ODD = -OSTRESULTSINSPACERADIOLOGYHAVEBEENOBTAINEDDURINGSHORT DURATIONSPACE MISSIONS IN ,%/ (OWEVER SOME OBSERVATIONS WERE MADE ON SPECIMENS ʅOWN ON BOARD FREE ʅYING SATELLITES FOR SEVERAL YEARS AS WELL AS ON THE )33 4HE BIOLOGICAL

3PACE"IOLOGY



SYSTEMS INVESTIGATED INCLUDE BACTERIAL SPORES PLANT SEEDS AND ANIMAL EGGS WHICH WEREALTERNATELYSANDWICHEDBETWEENNUCLEARTRACKDETECTORSALLOWINGBOTHAPRECISE DETERMINATIONOFTHEBIOLOGICALREGIONPENETRATEDBYTHEPARTICLESANDADETERMINATION OFTHECHARGEANDENERGYOFEACHPARTICLEPASSINGTHROUGH#HROMOSOMEDAMAGEAND ABNORMALITIESWERESEEN)NGENERAL SEEDSARELESSSENSITIVETHANDEVELOPINGEMBRYOS ORGROWINGPLANTS WHICHMAYBEBECAUSETHEIRCELLSARENOTACTIVELYDIVIDING)TIS DIFʄCULTTODETERMINEIFTHESEEFFECTSINLOWERORGANISMSWILLLEADTOTUMORINDUCTION SHORTENING OF LIFE OR CHROMOSOME ABERRATION IN ORGANISMS WITH LONGER LIFE SPANS ;0LANELETAL = 3EVERALSTUDIESHAVEBEENPERFORMEDTOTRYANDDETERMINEWHICHRADIATIONISTHE MOSTDAMAGING OREVENWHETHERTHEDAMAGEWASSOLELYDUETORADIATIONATALL3OME STUDIESSHOWTHATSTANDARDRADIOPROTECTANTCHEMICALSLIKECYSTEINE AMINOETHYLIOTHIO UREA AND METHOXYTRYPTAMINEDONȀTSTOPTHEDAMAGE4HISMIGHTINDICATETHATTHE LOW ENERGY INDIRECTRADIATIONISNOTPRIMARILYATFAULT(OWEVER ONSOMEOFTHEʅIGHTS FOR WHICH DAMAGE WAS FOUND THE DURATION WAS SHORT ENOUGH THAT GALACTIC COSMIC RADIATIONDOSAGESWERERATHERLOW/FCOURSEHIGH ENERGYPARTICLESREMAINAPOSSIBLE THREAT BUTSOMEOFTHECHROMOSOMALDAMAGEANDABNORMALITIESCOULDALSOBEATTRIB UTEDTOOTHERENVIRONMENTALFACTORS LIKEMICROGRAVITY/NTHEOTHERHAND EXPERIMENTS WITHPROTOZOAANDBACTERIASUGGESTTHATSMALLDOSESOFRADIATIONMAYACTUALLYBEBEN EʄCIALBECAUSESMALLDOSESELICITSTRESSRESPONSESANDHAVEBEENSHOWNTOINCREASE $.!REPAIR;0LANELETAL (AMMONDETAL = -ICROLESIONSOFCULTUREDRETINACELLSINDUCEDBYSINGLEHEAVYIONSWEREʄRSTDIS COVEREDVIASPACEʅIGHTEXPERIMENTS4HESEʄNDINGSINITIATEDBIOLOGICALINVESTIGATIONS USINGPARTICLEACCELERATORSON%ARTH(OWEVER THERESULTSOFGROUNDǻANDSPACE BASED STUDIESAREOFTENCONʅICTING&OREXAMPLE AHIGHERNUMBEROFMUTATIONSWEREOBSERVED INBIOLOGICALSYSTEMSEG LARVAEOF$ROSOPHILA EXPOSEDTOANȃARTIʄCIALȄRADIATION SOURCEWHILEINORBITCOMPAREDTOGROUNDCONTROLS4HISDIFFERENCESUGGESTSTHEPOS SIBLEEXISTENCEOFACOMBINEDEFFECTOFRADIATIONANDMICROGRAVITY THEREPAIROFRADI ATION INDUCEDLESIONSBEINGALTEREDINSPACE;0LANELETAL = 4HISILLUSTRATESTHEDIFʄCULTYOFDIFFERENTIATINGBETWEENTHEEFFECTSOFTHESEVERAL FACTORSINEVITABLYPRESENTDURINGSPACEʅIGHT&ORTHISREASON SOMEBIOLOGICALEFFECTS ANDTHEIRPROTECTION CANBESTUDIEDONLYINSPACE!NEXPERIMENTONBOARDTHE)33 UTILIZES A PHANTOM TORSO IE PART DUMMY PART DOSIMETER IMBEDDED MOCK UP OF A HUMANȀSUPPERBODY MINUSASETOFARMS BUILTTODETERMINETHEEFFECTSOFRADIATIONON THEHUMANBODY&IGURE $OSIMETERSAREMOUNTEDATCRITICALORGAN TISSUELOCA TIONSWITHINTHEDUMMYWHERECRITICALORGANSARELOCATEDTHEHEAD THEHEART THELIVER ANDKIDNEYS4HEDOSIMETERSRECORDTHELEVELOFRADIATIONRECEIVEDASAFUNCTIONOF TIME/THERINSTRUMENTSMOUNTEDONTHEOUTSIDEOFTHE)33MEASURETHESPECTRUMOF PARTICLESTHATʄRSTHITTHE)33SHIELDING!STHEYGOTHROUGHTHESTATIONWALLANDTHE DUMMY THERADIATIONISMODIʄED4HESECONDARYRADIATIONMAYHAVEADIFFERENTEFFECT ONTISSUETHANTHEPRIMARYRADIATION3OTHERADIATIONSPECTRUMISMEASUREDBEFOREAND AFTERITHITSTHEDUMMY4HEINFORMATIONGAINEDFROMTHISANDSUBSEQUENTEXPERIMENTS SEE #HAPTER  3ECTION  WILL HELP DETERMINE THE BEST TYPES OF MATERIALS AND METHODSFORSHIELDINGHUMANCREW &ORHUMANMISSIONTO-ARS CONSIDERABLYBETTERQUANTITATIVEDATAONLOW ENERGY TRANSFERRADIATIONDOSERATESBEYONDTHEMAGNETOSPHEREARESTILLREQUIRED)NPARTICULAR

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Figure 2.27. ISS Astronauts Display the Phantom Torso That Monitors the Radiation Level at Various Depths Within Its Tissues When Placed Inside or Outside the ISS. (Credit NASA).

BETTERPREDICTABILITYOFTHEOCCURRENCEANDMAGNITUDEOFENERGETICPARTICLESFROMSOLAR ʅARESISNEEDED GIVENTHATRADIATIONFROMSOLARʅARESCANBELIFETHREATENINGINRELA TIVELYSHORTTIMEPERIODS

 &ACILITIESFORSPACEBIOLOGY 

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)NSIDETHE#OLUMBUSMODULEISTHEDEDICATED"IOLOGICAL,ABORATORY"IO,AB 4HIS DOUBLE SIZEDRACKDEVELOPEDBY%3!ISUSEDTOPERFORMSPACEBIOLOGYEXPERIMENTSON MICROORGANISMS CELLS TISSUECULTURES SMALLPLANTS ANDSMALLINVERTEBRATES"IO,AB INCLUDESANINCUBATOR AMICROSCOPE ANDSPECTROPHOTOMETER4WOCENTRIFUGESPROVIDE ARTIʄCIALGRAVITY)TALSOHASAGLOVEBOXANDACOMBINATIONOFCOOLERANDFREEZERUNITS 4HE*APANESECOUNTERPARTOF"IO,ABISTHE3AIBOMEANINGȃLIVINGCELLSȄ %XPERIMENT 2ACK WHICHISCOMPRISEDOFACLEANBENCH AGLOVEBOXWITHMICROSCOPE ANDACELL BIOLOGY EXPERIMENT FACILITY WITH INCUBATORS A CENTRIFUGE AND SENSORS TO MONITOR ATMOSPHERICGASES&IGURE  /NTHEEXTERNALSURFACESOFTHE:VEZDASERVICEMODULEANDTHE#OLUMBUSMODULE ISTHE%XPOSEFACILITY WHICHALLOWSSHORTǻANDLONG DURATIONEXPOSUREOFEXPERIMENTS TO SPACE CONDITIONS AND SOLAR 56 RADIATION 4HE %XPOSE FACILITY CAN ACCOMMODATE EXPERIMENTSINPHOTOPROCESSING PHOTOBIOLOGY ANDEXOBIOLOGY 4HE)33ISALSOEQUIPPEDWITHGROWTHCHAMBERSANDANIMALHABITATSWHERETEM PERATURE ILLUMINATION AND ATMOSPHERIC COMPOSITION ARE CONTROLLED INDEPENDENTLY 4HEY HAVE THE CAPABILITY TO MAINTAIN AND MONITOR MICROBIAL ANIMAL AQUATIC AND PLANTCELLANDTISSUECULTURESFORUPTODAYS4HEAQUATICHABITATACCOMMODATES

3PACE"IOLOGY



Figure 2.28. A Crewmember Conducts a Biology Experiment Facility in the Saibo rack in the Kibo Laboratory of the ISS. (Credit NASA).

SMALLFRESHWATERORGANISMSTOSUPPORTEGGGENERATIONSTUDIESFOREXAMINATIONATALL LIFE STAGES !NIMAL HABITATS ARE CAPABLE OF HOUSING UP TO SIX RATS OR A DOZEN MICE 4HESE HABITATS ARE COMPATIBLE WITH ANOTHER COMPARTMENT ACCOMMODATING PREGNANT MICEANDSUBSEQUENTLYTHEIROFFSPRINGFROMBIRTHTHROUGHWEANING0LANTUNITSAREABLE TOSUPPORTPLANTSPECIMENSOFVARIOUSHEIGHTSTHROUGHALLSTAGESOFGROWTHANDDEVEL OPMENT 4HE INSECT HABITAT SUPPORTS DROSOPHILES AND OTHER INSECTS FOR MULTIGENERA TIONAL STUDIES AND RADIATION BIOLOGY %GG INCUBATORS SUPPORT THE INCUBATION AND DEVELOPMENTOFSMALLREPTILIANANDAVIANEGGSPRIORTOHATCHING 4HESEUNITSINCLUDE (a) The NASA Advanced Biological Research System (ABRS) has two chambers to grow a variety of biological organisms, including plants, microorganisms, and small arthropods (insects and spiders). (b) The Biotechnology Specimen Temperature Controller (BSTC) can grow and maintain mammalian cell cultures in microgravity. (c) The European Modular Cultivation System (EMCS) is being used for multi-generation experiments and studies of gravitational effects on early development and growth in seeds and plants and other small organisms, such as worms and fruit flies. (d) The Eosteo Bone Culture System of the CSA provides the right conditions to grow bone cells in microgravity. (e) With two aquariums, automatic feeding systems, LED lights to generate day/ night cycle, and CCD cameras for observations, the Japanese Space Exploration Agency (JAXA) Aquatic Habitat (AQH) enables a variety of breeding experiments in space with small freshwater fish, such as Medaka or zebrafish.



&UNDAMENTALSOF3PACE-EDICINE

(f) For studies on organ function to embryonic development of mammals is the Mice Drawer System (MDS) developed by ASI and NASA. Research conducted with the MDS is an analog to the human research program, but allowing better focus at microscopic level. (g) Finally, the LADA Greenhouse is used for growing plants in the Russian segment of the ISS. Since its launch in 2002, it has supported a series of experiments on fundamental plant biology and space farming, growing multiple generations of sweet peas, wheat, tomatoes, and lettuce (for the enjoyment of the crew!).  "IOPROCESSING 4HE .!3! #OMMERCIAL 'ENERIC "IOPROCESSING !PPARATUS #'"! PROVIDES PRO GRAMMABLE ACCURATETEMPERATURECONTROLǻFROMCOLDSTOWAGETOACUSTOMIZABLEINCU BATORǻANDCANBEUSEDINAWIDEVARIETYOFBIOLOGICALSTUDIES SUCHASPROTEINCRYSTAL GROWTH SMALLINSECTHABITATS PLANTDEVELOPMENT ANTIBIOTIC PRODUCINGBACTERIA AND CELLCULTURESTUDIES %3!ALSOUSESTHE0ROTEIN#RYSTALLIZATION$IAGNOSTICS&ACILITY0#$& TOSTUDY THEPROTEINCRYSTALGROWTHCONDITIONSBYWAYOFNON INTRUSIVEOPTICALTECHNIQUESLIKE $YNAMIC,IGHT3CATTERING$,3 -ACH :EHNDER)NTERFEROMETRY-:) ANDCLASSICAL MICROSCOPY 5NDERSTANDING HOW CRYSTALS GROW IN PURELY DIFFUSE CONDITIONS HELPS DEʄNETHEBESTSETTINGSTOGETORGANICCRYSTALSASPERFECTASPOSSIBLE4HESECRYSTALSARE THENPRESERVEDANDANALYZEDON%ARTHORON BOARDTODEDUCETHETHREE DIMENSIONAL SHAPEOFPROTEINS  3TORAGEANDOPERATIONS  &REEZERS &REEZERSALLOWFREEZINGSTORAGE ANDTRANSPORTATIONOFSAMPLESCOLLECTEDON)33FOR LATERRETURNTO%ARTH4HEREARETHREE%3! BUILTAND.!3! OPERATEDFREEZERSCALLED -INUS%IGHTY $EGREE,ABORATORY&REEZERFOR)33-%,&) WHICHEACHHAVEAVOLUME OF,OFSAMPLESSTOREDATTEMPERATURESRANGINGFROMm#TOASLOWASȪm# ! .!3! 'ENERAL ,ABORATORY !CTIVE #RYOGENIC )33 %QUIPMENT 2EFRIGERATOR ',!#)%2 ALSOSERVESASANON ORBITULTRA COLDFREEZERASLOWASȪm# ANDHAS AVOLUMEOF,4HESEFREEZERSHAVESPECIALȃDAMPINGȄMECHANISMSTHATENSURE THAT THIS MICROGRAVITY LEVEL IS UNDISTURBED BY HUMAN OR MACHINE ACTIVITY 3MALLER DEVICES WITHAVOLUMEOF,ANDTEMPERATURESRANGINGFROMȪm#TOm# CAN BEUSEDEITHERASAFREEZER REFRIGERATOR ORINCUBATOR4HE+RIOGEM -ISA2USSIAN REFRIGERATOR INCUBATORFORSTOWAGEOFBIOLOGICALSAMPLES  'LOVEBOXES 0ERIODICSAMPLINGISPERFORMEDAUTOMATICALLYORBYTHEONBOARDCREW INSUCHAWAY AS TO LEAVE THE REMAINING MATERIAL UNDISTURBED 3AMPLING IS OBVIOUSLY CAREFULLY PLANNEDANDMINIMIZEDTOPRECLUDEVIBRATIONSANDOTHERUNWANTEDGRAVITATIONALFORCES 'LOVEBOXES PROVIDE AN ENCLOSED WORKSPACE USED FOR PERFORMING EXPERIMENTS AND HANDLINGRESEARCHORGANISMS4HEYPROVIDECONTAINMENTOFEXPERIMENTS ANDASAFE ENVIRONMENTFORRESEARCHWITHLIQUIDS COMBUSTION ANDHAZARDOUSMATERIALSONBOARD THE )33 &IGURE   4HE LABORATORY ʄXED %3!.!3! -ICROGRAVITY 3CIENCE

3PACE"IOLOGY



Figure 2.29. An Astronaut Works on a Biology Experiment Inside the Microgravity Science Glovebox (MSG) in the Columbus Laboratory of the ISS. (Credit NASA).

'LOVEBOX -3' ENSURES THAT HAZARDOUS MATERIALS DO NOT ʅOAT ABOUT THE CABIN #REWMEMBERS ACCESS THE WORK AREA THROUGH PORTS EQUIPPED WITH RUGGED SEALED GLOVES!VIDEOSYSTEMANDDATADOWNLINKSALLOWFORCONTROLOFTHEENCLOSEDEXPERI MENTSFROMTHEGROUND!0ORTABLE'LOVE"OX0'" ISASMALLERGLOVEBOXTHATCAN BETRANSPORTEDAROUND)33ANDUSEDTOPROVIDETWOLEVELSOFCONTAINMENTFOREXPERI MENTSINANYLABORATORYMODULE4HREELEVELSOFCONTAINMENTCANEVENBEACHIEVEDBY PLACINGTHE0'"INSIDETHELARGERVOLUMEOFTHE-3'  #ENTRIFUGES 3EVERALON BOARDCENTRIFUGESAREPROVIDEDWITHINTHEFACILITIESDESCRIBEDABOVE4HESE CENTRIFUGESPROVIDEA GCONTROLFORMICROGRAVITYEXPERIMENTS(OWEVER AMISSING TOOLFORSPACEBIOLOGYONBOARDTHE)33ISAMULTI PURPOSECENTRIFUGETHATWOULDPRO VIDETHECAPABILITYTOEXPLOREARANGEOFGRAVITYLEVELSBETWEENȪANDGINORDER TOSTUDYGRAVITYTHRESHOLDSFORCERTAINPHENOMENA4HISMULTI GRAVITYRESEARCHFACILITY WOULDHELPDETERMINETHEOPTIMALPARAMETERSFORARTIʄCIALGRAVITYINHUMANS !#ENTRIFUGE!CCOMMODATION&ACILITY#!& WASORIGINALLYDESIGNEDPLANNEDFOR ʅYINGONBOARDTHE)33!LTHOUGHTHEʅIGHTMODELWASBUILTANDREADYTOLAUNCH THE PROJECT WAS CANCELLED 4HIS .!3! *!8! FACILITY COULD PROVIDE ARTIʄCIAL GRAVITY RANGINGFROMȪTOG!PPROPRIATEINCUBATORSANDGROWTHCHAMBERSWEREPROVIDED FORCELLS SIMPLEORGANISMS PLANTS ANDANIMALS3OMEHABITATSWOULDHAVEHADTHE EXPERIMENTALCAPABILITYOFSELECTABLEGRAVITYLEVELSOFUPTOGBYBEINGMOUNTEDON A MDIAMETERCENTRIFUGE/THERHABITATSWEREEQUIPPEDWITHINTERNALCENTRIFUGES



&UNDAMENTALSOF3PACE-EDICINE

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&UNDAMENTALSOF3PACE-EDICINE

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#HAPTER 4HE.EURO 3ENSORY3YSTEMIN3PACE

4O BE AWARE OF THE ENVIRONMENT ONE MUST SENSE OR PERCEIVE THAT ENVIRONMENT 4HE BODY SENSES THE ENVIRONMENT BY THE INTERACTION OF SPECIALIZED SENSORY ORGANS WITHONEASPECTORANOTHEROFTHEENVIRONMENT4HECENTRALNERVOUSSYSTEMUTILIZES THESESENSATIONSTOCOORDINATEANDORGANIZEMUSCULARMOVEMENTS SHIFTFROMUNCOM FORTABLEPOSITIONS ANDADJUSTPROPERLY/NERELEVANTQUESTIONISȃWHATISTHERELATIVE CONTRIBUTIONOFGRAVITYTOTHESESENSORYANDMOTORFUNCTIONSȄ4HISCHAPTERREVIEWS THEEFFECTSOFMICROGRAVITYONTHEFUNCTIONINGOFTHESENSORYORGANSPRIMARILYUSEDFOR BALANCEANDSPATIALORIENTATION$ISORIENTATIONANDMALAISESOFREQUENTLYENCOUNTERED DURINGEARLYEXPOSURETOMICROGRAVITYANDUPONRETURNTO%ARTHAREDESCRIBED4HEORIES ANDACTUALDATAREGARDINGTHEROLEOFTHECENTRALNERVOUSSYSTEMINTHEADAPTATIONOF SENSORY MOTORFUNCTIONS INCLUDINGTHECONTROLOFPOSTURE EYEMOVEMENTS ANDSELF ORIENTATION TOCHANGINGENVIRONMENTALGRAVITYLEVELSAREEXPLORED&ORACOMPREHEN SIVEREVIEWOFSPACERESEARCHCONDUCTEDINTHISAREASINCETHEBEGINNINGOFSPACEʅIGHT THE READER IS REFERRED TO THE BOOK .EUROSCIENCE IN 3PACE ;#L¦MENT AND 2ESCHKE =&IGURE 

 4HEPROBLEMSPACEMOTIONSICKNESS 4HENEURO VESTIBULARSYSTEMCONSISTSOFORGANSSENSINGTHEACCELERATIONENVIRONMENT NERVES TRANSMITTING THIS INFORMATION TO THE SPINAL CORD AND BRAIN AND THE CENTRAL NERVOUSSYSTEM#.3 THATINTEGRATESTHISINFORMATIONSOTHATWECANDETERMINEOUR POSITIONANDORIENTATIONRELATIVETOTHEENVIRONMENT4HEVESTIBULARORGANSINTHEINNER EAR DETECT AND MEASURE LINEAR AND ANGULAR ACCELERATIONS 4HESE RESPONSES ALREADY COMPLEX ARE FURTHER INTEGRATED WITH VISUAL AND PROPRIOCEPTIVE INPUTS &IGURE   )NMICROGRAVITY SOMEOFTHESESIGNALSAREMODIʄED LEADINGTOMISINTERPRETATIONAND INADEQUATERESPONSESBYTHEBRAIN/NEOFTHESERESPONSESISSPACEMOTIONSICKNESS 3-3 &IGURE  3-3ISASPECIALFORMOFMOTIONSICKNESSTHATISEXPERIENCEDBYSOMEINDIVIDUALS DURINGTHEʄRSTSEVERALDAYSOFEXPOSURETOMICROGRAVITY4HESYNDROMEMAYINCLUDE SUCHSYMPTOMSASDEPRESSEDAPPETITE ANONSPECIʄCMALAISE LETHARGY GASTROINTESTINAL DISCOMFORT NAUSEA ANDVOMITING!SINOTHERFORMSOFMOTIONSICKNESS THESYNDROME

 4HEWORDSȃSENSEȄANDȃPERCEIVEȄAREFROM,ATINWORDSȃSENSEȄMEANSȃTOFEELȄ WHEREASȃPERCEIVEȄ MEANSȃTOTAKEINTHROUGHȄ IE TORECEIVEANIMPRESSIONOFTHEOUTSIDEWORLDTHROUGHSOMEPORTIONOFTHE BODY

G. Clément, Fundamentals of Space Medicine, Space Technology Library 23, DOI 10.1007/978-1-4419-9905-4_3, © Springer Science+Business Media, LLC 2011





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Figure 3.1. Astronauts on Board the ISS Wear Different Colors and Patterns of Polo Shirts for Ease of Identification of Crewmates When They Are Not Right Side Up. (Credit NASA).

Figure 3.2. The Eyes, the Inner Ear and the Special Receptors in the Skin, Muscles and Joints All Participate in Maintaining Posture and Balance, and Assist in Our Movements.

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Figure 3.3. Inputs and Outputs of the Neuro-Vestibular System. The Information from the Various Sensory Organs First Reaches the Brainstem and Cerebellum. We Are Not Consciously Aware of What Is Going on in Our Busy Body When We Sit, Stand, Walk, or Run. However, Certain Sensations Do Eventually Reach the Cerebral Cortex, and Through Them We Remain Consciously Aware of the Relative Positions of Our Body Parts. Motion Sickness Might Be Caused by a Conflict Among Sensory Inputs Through Connections with the Autonomic Nervous System.

MAYINDUCEANINHIBITIONOFSELF MOTIVATION WHICHCANRESULTINDECREASEDABILITYTO PERFORM DEMANDING TASKS IN THOSE PERSONS WHO ARE MOST SEVERELY AFFECTED 'ASTROINTESTINALSYMPTOMSHAVETHEIRONSETFROMMINUTESTOHOURSAFTERORBITALINSER TION%XCESSIVEHEADMOVEMENTEARLYON ORBITGENERALLYINCREASESTHESESYMPTOMS 3YMPTOMRESOLUTIONUSUALLYOCCURSBETWEENANDH WITHAREPORTEDRANGEOF ǻH ANDRECOVERYISRAPID %VENIFSOMEONEDOESNȀTLITERALLYGETSICKTOTHEIRSTOMACH THEYMAYFEELALESS DRAMATICMOTIONSICKNESSEFFECTKNOWNASȃSOPITESYNDROMEȄ CHARACTERIZEDBYLETH ARGY MENTALDULLNESS ANDDISORIENTATION-ANYASTRONAUTSHAVENOTICEDTHISEFFECT WHICHTHEYCALLȃMENTALVISCOSITY ȄȃSPACEFOG ȄORȃTHESPACESTUPIDSȄ 4HEREWERENOREPORTSOF3-3INTHE-ERCURYAND'EMINIPROGRAMS WHILEOF THE!POLLOASTRONAUTSEXHIBITEDSYMPTOMS4HEINCIDENCEDURINGTHE3KYLABMISSIONS INCREASEDTO!BOUTTWO THIRDSOFTHESPACESHUTTLEASTRONAUTSAND3OYUZCOSMO NAUTSEXPERIENCEDSOMESYMPTOMSOF3-34HEREARENOSTATISTICALLYSIGNIʄCANTDIF FERENCES IN SYMPTOM OCCURRENCE BETWEEN PILOTS VERSUS NON PILOTS MALES VERSUS FEMALES DIFFERENT AGE GROUPS OR NOVICES ʄRST TIME ʅYERS VERSUS VETERANS REPEAT ʅYERS !NASTRONAUTȀSSUSCEPTIBILITYTO3-3ONHISHERʄRSTʅIGHTCORRECTLYPREDICTED SUSCEPTIBILITYONTHESECONDʅIGHTINOFTHECASES;$AVISETAL =)NOTHER WORDS ONEASTRONAUTWHOHASBEENSICKDURINGHISORHERʄRSTʅIGHTISLIKELYTOBESICK AGAINDURINGSUBSEQUENTʅIGHTS



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3-3 AFFECTS A SIMILAR PERCENTAGE OF BOTH 53 AND 2USSIAN CREWS 3YMPTOM R ECURRENCEATLANDING ALSOCALLEDȃ-ALDE$¦BARQUEMENT ȄREPORTEDLYAFʅICTSOF 2USSIANCOSMONAUTSRETURNINGFROMLONGERMISSIONS;'ORGILADZEAND"RYANOV = .OREPORTSOFMALDED¦BARQUEMENTWERENOTEDINTHESPACESHUTTLEPROGRAM(OWEVER MANY ASTRONAUTS RETURNING TO %ARTH AFTER LONG DURATION STAY ON BOARD THE )33 NOW EXPERIENCETHISSYNDROME4HESEVERITYOFTHESYMPTOMSANDTHEFUNCTIONALRECOVERY AFTERTHEʅIGHTSEEMTOBEDIRECTLYPROPORTIONALTOTHETIMEONORBIT -ICROGRAVITYBYITSELFDOESNOTINDUCESPACESICKNESS4HEREWERENOREPORTSOF MOTIONSICKNESSDURINGTHE-ERCURYAND'EMINISPACEʅIGHTS!STHEVOLUMEOFSPACE CRAFTHASINCREASED ALLOWINGFORMOREMOBILITY THEINCIDENCEOF3-3HASINCREASED AS WELL -OVEMENTS THAT PRODUCE CHANGES IN HEAD ORIENTATION SEEM NECESSARY TO INDUCE 3-3 SYMPTOMS )N PARTICULAR MANY CREWMEMBERS REPORTTHAT VERTICAL HEAD MOVEMENTSROTATIONINTHEPITCHORROLLPLANES AREMOREPROVOCATIVETHANHORIZONTAL YAW HEADMOVEMENTS;/MANETAL =(OWEVER ONCESICKNESSHASBEENWELL ESTABLISHED HEADMOVEMENTSINANYPLANEAREGENERALLYMINIMIZEDBYTHEAFFECTED CREWMEMBER)NDEED MOVEMENTOFANYKINDISFREQUENTLYRESTRICTEDUNTILTHEASTRO NAUTISONTHEROADTORECOVERY (EAD OR FULL BODY MOVEMENTS MADE UPON TRANSITIONING FROM MICROGRAVITY TO A GRAVITATIONALʄELDLESSTHANTHATON%ARTH ANDVICEVERSA MAYNOTBEASPROVOCATIVE )TISINTERESTINGTONOTETHATOFTHE!POLLOASTRONAUTSWHOWALKEDONTHE-OON ONLY REPORTEDMILDSYMPTOMS SUCHASSTOMACHAWARENESSORLOSSOFAPPETITE PRIORTO THEIR%6!.ONEREPORTEDSYMPTOMSWHILEINTHEONE SIXTHGRAVITYOFTHELUNARSUR FACE AND NO SYMPTOMS WERE NOTED UPON RETURN TO WEIGHTLESSNESS AFTER LEAVING THE -OONSURFACE;(OMICKAND-ILLER = 4HERE ARE CONSIDERABLE INDIVIDUAL DIFFERENCES IN SUSCEPTIBILITY TO 3-3 AND CUR RENTLYITISNOTPOSSIBLETOPREDICTWITHANYACCURACYTHOSEWHOWILLHAVESOMEDIFʄ CULTYWITHSICKNESSWHILEINSPACE!LTHOUGHANTI MOTIONSICKNESSDRUGSOFFERSOME PROTECTIONAGAINST3-3 SOMEDRUGSIE SCOPOLAMINE MAYINTERFEREWITHTHEADAPTA TION PROCESS AND SYMPTOMS CONTROLLED BY THESE DRUGS ARE EXPERIENCED AGAIN ONCE TREATMENTCEASES 3YMPTOMS HAVE RARELY OCCURRED DURING EXTRAVEHICULAR ACTIVITY %6!  "ECAUSE MOSTSPACESICKNESSHASABATEDBYTHETHIRDDAYOFʅIGHT MISSIONRULESRESTRICT%6!S UNTIL THE THIRD MISSION DAY .EVERTHELESS SOME ASTRONAUTS MEDICATE PRIOR TO SPACE WALKING4HEMINIMUMʅIGHTDURATIONFORTHESPACESHUTTLEWASALSODAYS TOREDUCE THE PROBABILITY FOR ASTRONAUTS IN PARTICULAR THE PILOTS TO BE INCAPACITATED BY 3-3 SYMPTOMSPRIORTORE ENTRYANDLANDING;$AVISETAL =4HEFACTTHATTHESHUTTLE AND3OYUZDOCKTOTHE)33ONLYAFTERHAVINGSPENTDAYSINORBITREDUCESTHEOCCUR RENCEOF3-3INTHECREWWHENARRIVINGINALARGEOPENSPACESUCHASTHE)33 /THER ISSUES RELATED TO THE ADAPTATION OF THE CENTRAL NERVOUS SYSTEM THROUGH THE VESTIBULAR PATHWAYS INCLUDE A THE PERCEPTUAL EFFECTS AND ILLUSIONS OF FREE FALLING VISUALREORIENTATIONILLUSIONS ANDACROPHOBIAEPISODESFEAROFHEIGHT DURING%6! B DECREASED SENSORIMOTOR PERFORMANCE AND VISUAL SCENE OSCILLATION OSCILLOPSIA DURINGRE ENTRYC DISEQUILIBRIUMANDATAXIAWHENSTANDINGANDWALKINGAFTERLAND ING AND D G STATE ʅASHBACKS DURING UNUSUAL STIMULATION OF THE VESTIBULAR SYSTEM DURINGTHERE ADAPTATIONPERIODFOLLOWINGLANDING

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 6ESTIBULARFUNCTION 4HEGRAVITYVECTORISAFUNDAMENTALFACTORINHUMANSPATIALORIENTATION WHICHRESULTS FROMTHEINTEGRATIONOFACOMPLEXOFSENSORYINPUTSCOMINGFROMTHEVESTIBULARORGANS INTHEINNEREAR THEEYES MOSTLYFROMPERIPHERALRETINA ANDTACTILEANDPROPRIOCEPTIVE RECEPTORSLOCATEDINTHESKIN JOINTS MUSCLES ANDVISCERA 

4HEVESTIBULARSYSTEM

 4HEVESTIBULARENDORGANS 4HEVESTIBULARSYSTEMȀSMAINPURPOSEISTOCREATEASTABLEPLATFORMFORTHEEYESSOTHAT WECANORIENTTOTHEVERTICALǻUPISUPANDDOWNISDOWNǻANDMOVESMOOTHLY4HE INNEREARCONTAINSTWOBALANCE SENSINGSYSTEMSONEISSENSITIVETOLINEARACCELERATION THEOTHERTOANGULARACCELERATION&IGURE  4HELINEARACCELERATIONSENSINGSYSTEMSENDSMESSAGESTOTHEBRAINASTOHOWTHE HEADISTRANSLATEDORPOSITIONEDRELATIVETOTHEFORCEOFGRAVITY)TCONTAINSTWOTINYSACS ʄLLEDWITHʅUID THESACCULEANDTHEUTRICLE LINEDALONGTHEIRINNERSURFACEWITHHAIR CELLSOFVARIOUSLENGTHS/VERLYINGTHEHAIRCELLSISAGELATINOUSMATRIXTHEOTOCONIA CONTAINING SOLID CALCIUM CARBONATES CRYSTALS THE OTOLITHS MEANING ȃEAR STONEȄ IN 'REEK  $URING LINEAR ACCELERATION THE CRYSTALS BEING DENSER THAN THE SURROUNDING ʅUID WILLTENDTOBELEFTBEHINDDUETOTHEIRINERTIA)THASBEENDEMONSTRATEDTHATTHE RESULTANTBENDINGOFTHECILIACAUSESCELLEXCITATIONWHENTHEBENDINGISTOWARDTHE KINOCILIUM THE LONGEST HAIR CELL AND INHIBITION WHEN AWAY FROM THE KINO CILIUM $URINGHEADMOTION THEWEIGHTANDMOVEMENTOFTHEOTOLITHSSTIMULATETHENERVEEND INGSSURROUNDINGTHEHAIRCELLSANDGIVETHEBRAININFORMATIONONMOTIONINAPARTICULAR DIRECTIONUP DOWN FORWARD BACKWARD RIGHT LEFT ORTILTINTHESAGITTALPITCH ORTHE FRONTALROLL PLANE

Figure 3.4. Left: Schematic of the Vestibular System in the Inner Ear Showing the Three Semicircular Canals (Anterior, Posterior, Horizontal) and the Two Otolith Organs (Utricle and Saccule). Right: Otoliths Are Small Particles of Calcium Carbonate in the Gel-Like Membrane Layer Situated Over the Sensory Hairs (Stereocilia) of the Utricles and Saccules. When the Head Moves or Is Tilted Relative to Gravity, the Membrane Exerts a Shear Force on the Cilia, Which in Turn Stimulates the Hair Cells. The Hair Cells Signal the Corresponding Information Via the Nerve Fibers to the Central Nervous System, Where the Sensation of Motion or Tilt Results.



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4HE ANGULAR ACCELERATION SENSING SYSTEM COMPRISES THREE SEMICIRCULAR CANALS 4HESYSTEMDETECTSANGULARACCELERATIONTHROUGHTHEINERTIALMOVEMENTOFTHELIQUID THE ENDOLYMPH WITHIN EACH CANAL AND PROVIDES THE BRAIN WITH INFORMATION ABOUT ROTATIONABOUTTHETHREEAXESYAW PITCH ANDROLL4HESEMICIRCULARCANALSDONOTREACT TOTHEBODYȀSPOSITIONWITHRESPECTTOGRAVITY4HEYREACTTOACHANGEINTHEBODYȀS POSITION )N OTHER WORDS THE SEMICIRCULAR CANALS DO NOT MEASURE MOTION ITSELF BUT CHANGEINMOTION.OTSURPRISINGLY THESEMICIRCULARCANALSARENOTAFFECTEDBYSPACE ʅIGHT AS SHOWN BY THE ABSENCE OF CHANGES IN THE PERCEPTION OF ROTATION OR IN THE COMPENSATORYEYE MOVEMENTSINRESPONSETOROTATIONBOTHIN ʅIGHTANDAFTERʅIGHT SEE3ECTIONBELOW   ,INEARACCELERATIONANDGRAVITY 7HENOURHEADISHORIZONTALTHEHAIRCELLSINTHEUTRICLESARENOTBENTANDTHISSTIMULA TIONISINTERPRETEDASSIGNIFYINGȃNORMALPOSTUREȄ)FOURHEADISTILTEDFORWARD THE OTOLITHSSHIFTDOWNWARDUNDERTHEACTIONOFGRAVITY BENDINGTHEHAIRCELLS)FWETRANS LATEBACKWARD AGAINTHEREISASHIFTOFTHEOTOLITHSFORWARDDUETOTHEINERTIALFORCES 4HUS ANEQUIVALENTDISPLACEMENTOFTHEOTOLITHSANDCONSEQUENTLYTHESAMEINFORMA TIONISCONVEYEDTOTHECENTRALNERVOUSSYSTEM CANBEGENERATEDWHENTHEHEADIS TILTEDmFORWARD ORWHENTHEBODYISTRANSLATINGATGBACKWARD&IGURE 4HIS EXAMPLESIMPLYILLUSTRATES%INSTEINȀSPRINCIPLESTATINGTHAT ON%ARTH ALLLINEARACCEL EROMETERSCANNOTDISTINGUISHBETWEENANACTUALLINEARACCELERATIONANDAHEADTILTRELA TIVETOGRAVITY

Figure 3.5. The Otoliths Bend the Hair Cells of the Utricles the Same Way When the Head Is Maintained at a Constant Tilt Angle of 30° Relative to Gravity and When the Whole Body in Translated Backwards at 0.5 g.

)NANORMALSITUATION THEBRAINWOULDEASILYDISTINGUISHBETWEENATILTOFTHEHEADRELATIVETOGRAVITYANDA HEADTRANSLATIONBYCOMPARINGTHESENSORYINFORMATIONFROMTHEOTOLITHORGANSWITHTHATFROMTHEEYESOR MUSCLEPROPRIOCEPTORS"UTINCOMPLETEDARKNESS THERECOULDBEACONʅICTBETWEENTHEPROPRIOCEPTIVEINPUT EG SIGNALINGTHATTHEHEADISTILTED ANDTHEOTOLITHINPUTEG SIGNALINGTHATTHEHEADTRANSLATES 



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/N%ARTH OTOLITHSIGNALSCANBEINTERPRETEDASEITHERLINEARMOTIONTRANSLATION OR ASTILTWITHRESPECTTOGRAVITY"ECAUSESTIMULATIONFROMGRAVITYISABSENTINWEIGHT LESSNESS INTERPRETATIONOFOTOLITHSIGNALSASTILTISINAPPROPRIATE&IGURE 4HEREFORE IT IS POSSIBLE THAT DURING ADAPTATION TO WEIGHTLESSNESS THE CENTRAL NERVOUS SYSTEM REINTERPRETSALLOTOLITHSIGNALSTOINDICATETRANSLATION4HISHYPOTHESISISKNOWNASTHE /TOLITH4ILT 4RANSLATION2EINTERPRETATION/442 4HISCENTRALREINTERPRETATIONWOULD PERSISTFOLLOWINGRETURNTO%ARTH ANDBEATTHEORIGINOFSPATIALDISORIENTATION UNTIL RE ADAPTATIONTOTHENORMALGRAVITYENVIRONMENTOCCURS;0ARKERETAL 9OUNG ETAL = %VIDENCEFORTHE/442HYPOTHESISCOMESFROMSUBJECTIVEREPORTSBYASTRONAUTS RETURNINGFROMSPACEʅIGHTWHOHAVEASENSEOFBODYTRANSLATIONWHENTHEYVOLUNTARILY PITCHORROLLTHEIRHEAD&OREXAMPLE MANYEXPERIENCEABACKWARDTRANSLATIONWHEN THEYPITCHTHEIRHEADFORWARD ORARIGHTWARDTRANSLATIONWHENTHEYROLLTHEIRHEADTO THELEFT4HEUTRICLEANDTHESACCULEARENOTLOCATEDATTHEAXISOFHEADROTATIONDURING ROLLORPITCHHEADMOVEMENTS4HEREFORE THISMOVEMENTMUSTEVOKEOTOLITHSTIMULA TION WHICH COULD READILY BE PERCEIVED AS TRANSLATION DURING AND IMMEDIATELY AFTER LANDING3UCHAMISLEADINGINTERPRETATIONOFOTOLITHSIGNALSMIGHTBERESPONSIBLEFOR THESTAGGERINGPOSTUREOFTHEASTRONAUTSASSOONASTHEYLAND4HEASTRONAUTSTENDTO LEANTOTHEOUTSIDEOFTHETURNWHENWALKINGANDTURNINGCORNERSIMMEDIATELYAFTER LANDING ALSOSUGGESTINGAMISEVALUATIONOFTHEAPPARENTVERTICALFROMOTOLITHSIGNALS 4HE/442HYPOTHESISHASBEENTHETHEORETICALBASISOFMUCHSPACERESEARCHONTHE NEURO VESTIBULARSYSTEMFORTHEPASTYEARS)WASFORTUNATEENOUGHTOBEABLETO PERFORM A SPACE EXPERIMENT THAT TESTED THIS HYPOTHESIS IN  4HIS EXPERIMENT WHICH ʅEW ON BOARD THE .EUROLAB 343  MISSION USED A HUMAN RATED CENTRIFUGE CONSTRUCTEDBY%3!;"UCKEYAND(OMICK =/N%ARTH WHENANINDIVIDUALIS ROTATEDINACENTRIFUGEINDARKNESS HESHESENSESTHEDIRECTIONOFTHERESULTANTGRAVITO INERTIALFORCEANDREGARDSTHISASTHEVERTICAL)FACENTRIFUGALFORCEEQUIVALENTTOGIS DIRECTED SIDEWAYS THE GRAVITO INERTIAL FORCE IS DISPLACED m RELATIVE TO THE UPRIGHT BODY ANDTHESUBJECTHASASENSEOFBEINGTILTEDBYmTOTHEOUTSIDE&IGURE  )NMICROGRAVITY HOWEVER THEGRAVITATIONALCOMPONENTISNEGLIGIBLEANDTHEGRAVITO INERTIAL FORCE IS EQUIVALENT TO THE CENTRIFUGAL FORCE 4HIS FORCE COULD BE INTERPRETED

Figure 3.6. In Microgravity, the Otoliths Are Stimulated by Head Translation, but Not by Head Tilt. Consequently, It Is Hypothesized that, After a Period of Adaptation, the Brain Reinterprets All Otolith Signals as Signaling Head Translation. (Credit Philippe Tauzin).



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Figure 3.7. On Earth, a Subject Sitting at the End of a Centrifuge Arm in Darkness Adopts the Direction of the Gravito-Inertial Force (GIF) as the New Direction of “Gravity”. In Microgravity, the GIF Is Equivalent to the Centrifugal Force and the Subject Could Perceive Either a Body Tilt or a Body Translation, Depending on the Interpretation of the Otolith Signals by the Central Nervous System.

EITHERASAmTILTOFTHEBODY ORAWHOLEBODYTRANSLATIONINTHEOPPOSITEDIRECTION $URING THE .EUROLAB MISSION FOUR ASTRONAUTS WERE ASKED TO REPORT THEIR PERCEIVED ANGLEOFTILTDURINGSTEADY STATECENTRIFUGATIONINDARKNESSTHROUGHOUTTHEʅIGHTAND DURINGTHEPOSTʅIGHTRE ADAPTATIONPERIOD#ENTRIFUGATIONWASALWAYSPERCEIVEDASTILT NOTTRANSLATION4HEREFORETHEʄNDINGSDONOTSUPPORTTHE/442HYPOTHESIS$ESPITE THEFACTTHATTHEOTOLITHSDONOTRESPONDTOHEADTILTINORBIT THEBRAINCONTINUESTO SENSE A STEADY STATE LINEAR ACCELERATION APPLIED TO THE OTOLITHS AS THE UPRIGHT IN ALL CIRCUMSTANCES 4HEDEBATEREGARDINGTHE/442HYPOTHESISISSTILLRAGING3OMEHAVEPROPOSEDTHAT THE/442ONLYOCCURSDURINGVOLUNTARYHEADMOVEMENTS ORONLYDURINGROTATIONAL HEAD MOVEMENTS OR THAT /442 MUST BE FREQUENCY DEPENDENT #ENTRIFUGATION BY APPLYINGVERYLOWFREQUENCYPASSIVELINEARACCELERATIONTOTHEENTIREBODY WOULDTHUS NOTELICIT/442)AMCURRENTLYCONDUCTINGFOLLOW UPSTUDIESONASTRONAUTSRETURNING FROMSPACEʅIGHT BYSPINNINGTHEMABOUTATILTEDAXISORTILTINGTHEMINROLLORINPITCH WHILETRANSLATINGATVARIOUSFREQUENCIESTOFURTHERADDRESSTHISHYPOTHESIS 4HE.EUROLABCENTRIFUGEEXPERIMENT HOWEVER BROUGHTANOTHERINTERESTINGRESULT !TTHEBEGINNINGOFTHEʅIGHT DURINGA GCENTRIFUGATIONINDARKNESS THEASTRONAUTS PERCEIVED A m TILT TO THE SIDE VERY MUCH LIKE ON %ARTH (OWEVER AS THE MISSION PROGRESSED THEYFELTMOREANDMORETILTED UNTILTHEYFELTAmTILTTOTHESIDEONʅIGHT DAY&IGURE 4HISSIMPLERESULTINDICATESTHATTHEBRAINDOESNOTCONTINUOUSLY CALCULATE THE DIRECTION OF GRAVITY BUT USES AN INTERNAL ESTIMATE OF GRAVITY WHOSE WEIGHTINGCHANGESDURINGSPACEʅIGHT4HEINTERNALESTIMATENORMALLYUSEDON%ARTH CARRIESOVERTOTHEEARLYPERIODOFEXPOSURETOWEIGHTLESSNESS ANDTHEREFORETHEASTRO NAUTSCONTINUETOPERCEIVEAmTILT DESPITETHEABSENCEOFSENSEDGRAVITY!FTERA PERIODOFADAPTATION THEINTERNALESTIMATEDECLINESTOZEROANDTHEASTRONAUTSPERCEIVE AFULLBODYTILTTOTHESIDE;#L¦MENTETAL  =

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 #HANGESINTHEVESTIBULARRECEPTORS !LTHOUGHITISDIFʄCULTTOMEASURECHANGESINTHEVESTIBULARENDORGANSDIRECTLY SEVERAL ATTEMPTSHAVEBEENMADETOEXAMINETHEQUESTIONȃ)STHEREANATOMICALANDPHYSIOLOG ICALCHANGESINTHEVESTIBULARENDORGANSANDTHEIRPRIMARYAFFERENTSAFTEREXPOSURETO MICROGRAVITYȄ %XPERIMENTSONFROGSHAVEREVEALEDNOALTERATIONOFTHESENSORYEPITHELIUMOFTHE VESTIBULARORGANOFADULTSRETURNEDFROMAN DAYSTAYABOARD-IR ORFOLLOWINGLARVAL DEVELOPMENTINMICROGRAVITY(OWEVER CHANGESINTHESTRUCTUREOFTHEOTOLITHCRYSTALS INRATSHADBEENOBSERVEDDURINGANEARLIER#OSMOS MISSION!DEGENERATIONOF THEOTOLITHCRYSTALSCOULDOCCURBECAUSEOFCHANGESINBODYCALCIUM PROTEINMETABO LISM ANDCALCIUMEXCHANGE)NADDITION ITISUNCLEARHOWMANYOFTHESECHANGESWERE DUETOTHEHIGHACCELERATIONSEXPERIENCEDBYTHEANIMALSDURINGTAKE OFFANDLANDING -ORERECENT3PACELABEXPERIMENTSINDICATEDNODELETERIOUSEFFECTSINTHEOTOLITHS OFRODENTSWHOʅEWASCOMPAREDWITHTHEGROUNDCONTROLS(OWEVER ANUNEXPECTED CHANGE FOUND DURING THE 3PACELAB 3,3  MISSION AND LATER CONʄRMED DURING THE .EUROLABMISSION WASANINCREASEBYAFACTOROF INTHENUMBEROFSYNAPSESIN HAIRCELLSFROMTHEIN ʅIGHTMACULAEASCOMPAREDWITHTHECONTROLDATA4HESEʄNDINGS SUGGESTTHATMATUREUTRICULARHAIRCELLSRETAINSYNAPTICPLASTICITY PERMITTINGADAPTATION TOANALTEREDENVIRONMENT#ONSISTENTWITHTHESERESULTSISDATATHATSHOWADECREASEIN SYNAPSE ACTIVITY IN CENTRIFUGED RATS 4HESE DATA SUGGEST THAT THE MACULAE ADAPT TO G FORCESCHANGESINEITHERDIRECTIONBYUP ORDOWN REGULATIONOFSYNAPTICCONTACTSIN ANATTEMPTTOMODULATENEURALINPUTSTOTHE#.3;2OSSAND4OMKO =2ECENT MORPHOMETRICSTUDIESOFTHEUTRICULARAREAPERFORMEDINTADPOLESFOLLOWINGSTAYSON BOARDTHE)33CONʄRMEDAVESTIBULARSENSITIZATIONINMICROGRAVITY 0RIMARYAFFERENTʄBERSOFTHEVESTIBULARNERVEARERELAYINGTHEINFORMATIONORIGI NATINGATTHEHAIRCELLSTOTHEBRAINSTEM7ITHINEACHNERVEAREALSOEFFERENTʄBERSFROM THE#.3THATPROVIDENEURALFEEDBACKTOMODULATETHEACTIVITYOFTHEPERIPHERALORGANS 4HERESTINGACTIVITYOFSINGLEOTOLITHAFFERENTSANDTHEIRRESPONSETOCENTRIFUGALFORCES WEREFOUNDTOBEDIFFERENTINMICROGRAVITYCOMPAREDTOTHEGROUNDCONDITIONINFROGS 2ECENTLY ASTUDYRECORDINGTHEVESTIBULARNERVEIMPULSEDATAFROMTHEOYSTERTOADʄSH DURINGTHE.EUROLABMISSIONCONʄRMEDTHESERESULTS/NTHEOTHERHAND THESPONTANE OUSʄRINGRATEOFSINGLEHORIZONTALSEMICIRCULARCANALSAFFERENTSDIDNOTCHANGEPOST ʅIGHT RELATIVE TO PREʅIGHT IN TWO ʅIGHT MONKEYS (OWEVER THESE MONKEYS WERE RESTRAINEDINALABORATORYCHAIR THUSPREVENTINGANYMOVEMENTSOFTHEHEADDURINGTHE ʅIGHT)TISKNOWNTHATMOVEMENTANDINTERACTIONWITHTHEENVIRONMENTARENECESSARY FACTORS TO DRIVE ADAPTIVE CHANGES &OR EXAMPLE VESTIBULAR PATIENTS SHOW A FASTER RECOVERYWHENMOVINGAROUNDAFTERVERTIGOCRISISORUNILATERALSURGERY &EWEXPERIMENTSADDRESSINGTHEEARLYDEVELOPMENTOFTHEVESTIBULARSYSTEMHAVE BEENCARRIEDOUTINSPACE4HISISANINTERESTINGRESEARCHTOPICGIVENTHATINALLSPECIES THEVESTIBULARSYSTEMBEGINSTORESPONDTOLINEARORANGULARACCELERATIONPRIORTOHATCH INGORBIRTH INCONTRASTTOHEARINGORVISION WHICHCANBEPOSTNATALINSOMESPECIES -AMMALIAN OFFSPRING EMERGE FROM THE BIRTH CANAL IN A SPECIES TYPICAL ORIENTATION WHICH FOR RATS AND HUMANS IS HEADʄRST &ETUSES TYPICALLY ACHIEVE THE APPROPRIATE ORIENTATIONVIAACTIVE IN UTEROBEHAVIOR0ERHAPSTHEVESTIBULARSYSTEMISEMPLOYED FOR THIS EARLY TASK )NDEED MANY INFANTS BORN IN THE BREACH POSITION ARE BORN WITH VESTIBULARDISORDERS!LSO THESO CALLEDȃRIGHTINGRESPONSE ȄBYWHICHTHENEWBORN

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MAMMALSACTIVELYADJUSTFROMASUPINETOAPRONEPOSITION ISDISRUPTEDBYINDUCED VESTIBULARDISORDERSDURINGDEVELOPMENT )NTHEDEVELOPMENTOFTHEVISUALSYSTEM ACTIVITYINTHERETINALPATHWAYINʅUENCES THESPECIʄCATIONOFTHOSECONNECTIONSTHATDETERMINEHOWVISUALINFORMATIONISPRO CESSEDINTHECEREBRALCORTEX)NEVERYOTHERSENSORYSYSTEMKNOWN ESPECIALLYTHOSE THAT MAKE UP THE NEURAL SPACE MAPS IN THE BRAINSTEM SENSORY STIMULATION HAS BEEN IMPLICATEDINTHEINITIALSPECIʄCATIONSOFTHECONNECTIONSANDPHYSIOLOGICALPROPERTIES OFTHECONSTITUENTNEURONS/NLYINTHEUTRICLEANDSACCULEGRAVITATIONALPATHWAYHASIT BEENIMPOSSIBLETOSTUDYTHEROLEOFSENSORYDEPRIVATION BECAUSETHEREISNOWAYTO DEPRIVETHESYSTEMOFGRAVITATIONALSTIMULATIONON%ARTH&ORTHISREASON EXPERIMENTS INMICROGRAVITYSHOULDBEPLANNEDTOTESTTHEHYPOTHESISTHATGRAVITYITSELFPLAYSAROLE INTHEDEVELOPMENTANDMAINTENANCEOFTHECOMPONENTSOFTHEVESTIBULARSYSTEM4HESE COMPONENTSINCLUDEBOTHTHEVESTIBULARRECEPTORSOFGRAVITYIE THESENSORYHAIRCELLS INTHEUTRICLEANDSACCULE VESTIBULARGANGLIONCELLSTHATFORMSYNAPSESWITHVESTIBULAR HAIRCELLS ANDVESTIBULARNUCLEINEURONS ANDTHEMOTORNEURONS4HELATTERRECEIVEINPUT FROMAXONSOFTHEVESTIBULARNUCLEUSNEURONSCOMPOSINGTHEVESTIBULARREʅEXPATHWAYS 4HEVESTIBULARSYSTEMALSORECEIVESINPUTSFROMTHEPROPRIOCEPTIVESYSTEM INVOLVEDIN THECONTROLOFMUSCLELENGTHANDTENSION ANDFROMTHEVISUALSYSTEM INVOLVEDINTHE CONTROLOFEYEMOVEMENTS,ITTLEISKNOWNABOUTTHEEXACTNATUREOFTHESEINTERACTIONS ANDVIRTUALLYNOTHINGCONCERNINGTHEDEVELOPMENTOFTHESECONNECTIONS 

4HEOTHERSENSES

)NCOMMONSPEECH ʄVEDIFFERENTSENSESAREUSUALLYRECOGNIZEDSIGHTVISION HEAR ING TASTE SMELL ANDTOUCH/FTHESE THEʄRSTFOURUSESPECIALORGANSǻTHEEYE EAR TONGUE ANDNOSE RESPECTIVELY WHEREASTHELASTUSESNERVEENDINGSTHATARESCATTERED EVERYWHEREONTHESURFACEOFTHEBODY ASWELLASINSIDETHEBODYVISCERALSENSATIONS  0ROPRIOCEPTIVESENSATIONSARISEFROMORGANSWITHINTHEBODY FROMMUSCLES TENDONS ANDJOINTS4OWHATLEVELTHESEʄVESENSESAREAFFECTEDBYSPACEʅIGHTISUNCERTAIN  6ISION 4HEVISUALENVIRONMENTINSPACEISALTEREDINSEVERALWAYS&IRST OBJECTSAREBRIGHTER UNDER SOLAR ILLUMINATION %ARTHȀS ATMOSPHERE ABSORBS AT LEAST  OF THE INCOMING SOLARRADIATION7ATERVAPOR SMOG ANDCLOUDSCANINCREASETHISABSORPTIONCONSIDER ABLY)NGENERAL THISMEANSTHATTHELEVELOFILLUMINATIONINWHICHASTRONAUTSWORK DURINGDAYLIGHTISABOUTONE FOURTHHIGHERTHANON%ARTH3ECOND THEREISNOATMO SPHERIC SCATTERING OF LIGHT 4HIS CAUSES AREAS NOT UNDER DIRECT SOLAR ILLUMINATION TO APPEARMUCHDARKER&IGURE  %ARLYANECDOTALREPORTSTHATORBITINGASTRONAUTSWEREABLETOSEEOBJECTSSUCHASSHIPS AIRPLANES ANDTRUCKSWITHTHENAKEDEYESUGGESTEDIMPROVEDVISUALACUITYINSPACE %XTENSIVE TESTING OF 'EMINI ASTRONAUTS WAS PERFORMED USING A SMALL SELF CONTAINED BINOCULAR OPTICAL DEVICE CONTAINING AN ARRAY OF HIGH AND LOW CONTRAST RECTANGLES !STRONAUTS JUDGED THE ORIENTATION OF EACH RECTANGLE AND INDICATED THEIR RESPONSE BY PUNCHINGHOLESINARECORDCARD!NOTHERMETHOD TAKINGINTOACCOUNTTHEPARTICULARITY OFTHEVISUALENVIRONMENTOFSPACEDESCRIBEDABOVE ALSOUSEDLARGERECTANGULARPATTERNS DISPLAYEDATGROUNDSITESIN4EXASAND!USTRALIA!STRONAUTSWEREREQUIREDTOREPORTTHE ORIENTATIONOFTHERECTANGLES$ISPLAYSWERECHANGEDINORIENTATIONBETWEENPASSESAND

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Figure 3.8. An Astronaut Uses a Still Camera to Photograph a View of Earth from a Window in the Cupola of the ISS. (Credit NASA).

ADJUSTMENTSFORSIZEWEREMADEINACCORDANCEWITHSLANTRANGE SOLARELEVATION ANDTHE VISUALPERFORMANCEOFASTRONAUTSONPRECEDINGPASSES2ESULTSWITHBOTHMEASUREMENT METHODSINDICATEDTHATVISUALPERFORMANCEWASNEITHERDEGRADEDNORIMPROVEDDURING SPACEʅIGHT 4HE ASTRONAUTSȀ REPORTED ABILITY TO DETECT MOVING OBJECTS AIRPLANES AND SHIPS WASPROBABLYBASEDONTHEDETECTIONOFTURBULENCEORWAVESBEHINDTHEVEHICLES !LSO THE COLOR CONTRAST MIGHT IMPROVE THE ABILITY TO IDENTIFY FEATURES AS !STRONAUT 7ILLIAM0OGUEDESCRIBEDITDURINGHIS3KYLABMISSIONȃ7EWEREABLETOSEEICEBERGS ABOUTAHUNDREDYARDSINDIAMETERQUITEEASILYBECAUSEOFTHEHIGHERCONTRASTOFWHITE ICEWITHTHEDARKBLUESEA;#L¦MENTAND2ESCHKE =Ȅ -OREREʄNEDVISUALTESTINGHASBEENPERFORMEDONSEVERALSHUTTLEʅIGHTSUSINGA SPECIALLY DESIGNED VISUAL TEST APPARATUS TO ASSESS CONTRAST SENSITIVITY PHORIA EYE DOMINANCE ʅICKER FUSION FREQUENCY STEREOPSIS AND ACUITY &IGURE   7ITH THE EXCEPTIONOFREDUCEDCONTRASTSENSITIVITY NOSIGNIʄCANTCHANGESDUETOWEIGHTLESSNESS WERE FOUND 4HESE CHANGES WERE TOO SMALL TO IMPACT OPERATIONAL PERFORMANCE (OWEVER IFCONTRASTSENSITIVITYCONTINUESTOCHANGEDURINGLONGEREXPOSURETOWEIGHT LESSNESS THEDECREMENTCOULDBECOMEOPERATIONALLYSIGNIʄCANT !N INTERESTING OBSERVATION IS THAT SOME ASTRONAUTS HAVE DESCRIBED A DECREASE IN THEIRABILITYTOSEECLEARLYATCLOSERANGEWHENINSPACE)NTERESTINGLYENOUGH MOSTOF THEASTRONAUTSEXPERIENCINGTHISCHANGEWEREINTHEIREARLYFORTIESANDCOULDSEECLEARLY WITHOUT READING GLASSES WHEN THEY WERE ON THE GROUND /NE THEORY AS TO WHY THIS MIGHTHAPPENISTHATTHEEYEISLIKEAWATERBALLOON2ESTITONATABLEANDITGETSLONGER ASITʅATTENSOUTWHICHISTHENORMALCONDITIONON%ARTH 0UTTHATBALLOONINSPACE ANDITSHORTENS BECOMINGMOREROUND4HEEYECOULDDOTHESAMETHINGANDWHENIT SHORTENSITBECOMESFARSIGHTED CAUSINGMOREDIFʄCULTYSEEINGOBJECTSUPCLOSE 2ECENT STUDIES REVEALED THAT OPTIC DISC EDEMA GLOBE ʅATTENING CHOROIDAL FOLDS HYPEROPICSHIFTS ANDRAISEDINTRACRANIALPRESSUREHAVEBEENOBSERVEDINAPPROXIMATELY  OF ASTRONAUTS ON LONG DURATION MISSIONS BOTH DURING AND AFTER SPACEʅIGHT )NSOMECASES THESECHANGESWERETRANSIENTANDINOTHERS THECHANGESWEREPERSISTENT WITH VARYING DEGREES OF VISUAL IMPAIRMENT &URTHERMORE THERE ARE INDICATIONS THAT



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Figure 3.9. Near-Visual Acuity Test Performed by an Astronaut on Board the Space Shuttle. (Credit NASA).

VISUALALTERATIONSANDCHANGESTOTHEEYEDISCEDEMA HAVEOCCURREDINASTRONAUTSON SPACESHUTTLEʅIGHTS BUTTHECONDITIONISNOTWELLDEʄNEDANDLACKSCONSISTENTDATA 4HESEALTERATIONSCOULDHAVEPROFOUNDMISSIONIMPACTSANDLONG TERMHEALTHIMPACTS FOR THE INDIVIDUAL SUCH AS A PERMANENT LOSS OF VISION /NE HYPOTHESIS FOR THESE CHANGESISINTRACRANIALHYPERTENSION DUETOTHEHEADWARDSHIFTOFBODYʅUIDSFOLLOW ING ORBITAL INSERTION -ICROGRAVITY IS KNOWN TO PRODUCE A HEADWARD SHIFT OF ǻ   M, OF ʅUID SEE #HAPTER  3ECTION   0HOTOGRAPHIC STUDIES SHOW A SIGNIʄCANTDECREASEINTHESIZEOFTHERETINALVASCULATUREAFTERʅIGHT)NTRAOCULARPRES SURERISESDURINGʅIGHTANDDROPSBELOWPRE ʅIGHTLEVELSAFTERLANDING4HERELATION SHIPBETWEENINTRACRANIALPRESSUREANDCHANGESINVISUALACUITYCOULDALSOBEDUETO EXCESSIVE #/ EXPOSURE /PERATIONAL DATA FROM )33 AND -IR IS BEING MINED AND STUDIES ARE PLANNED TO DETERMINE IF THERE IS INDEED A RELATIONSHIP BUT NO DEʄNITIVE INFORMATIONISCURRENTLYAVAILABLE )TISALSOWORTHNOTINGHERETHATTHELIGHTʅASHESPERCEIVEDBYTHEASTRONAUTSINTHE ABSENCEOFNORMALVISUALSTIMULATIONWERECAUSEDBYHEAVYIONIZEDCOSMICPARTICLES PASSINGTHROUGHRETINALCELLSSEE#HAPTER 3ECTION !LTHOUGHNOPERFORMANCE DISTURBANCEHASBEENASSOCIATEDWITHTHESELIGHTʅASHES ITISLIKELYTHATTHEʅASHES MASKTRANSIENTVISUALSTIMULI -ANY ASTRONAUTS HAVE REPORTED IMPAIRMENT IN EVALUATING DISTANCES BOTH ON THE -OONANDDURINGORBITALʅIGHTS4HECOLLISIONOFTHE0ROGRESSSPACECRAFTWITHTHE-IR

 4HE FOLLOWING QUOTES ARE EXERTED FROM THE POSTʅIGHT DEBRIEʄNGS OF THE ASTRONAUTS WHO WALKED ON THE -OONDURINGTHE!POLLO MISSION;'ODWIN = ȃ%VERYTHINGLOOKEDALOTSMALLERANDCLOSERTOGETHERINTHEAIRTHANITTURNEDOUTTOBEONTHEGROUND7HEN WEWEREONTHEGROUND THINGSTHATWEREFARAWAYLOOKEDALOTCLOSERTHANTHEYREALLYWERE4HETHINGTHAT CONFUSEDMEWASTHATWEWERESOCLOSETOTHE3URVEYORCRATER)DIDNȀTREALIZEWEWEREASCLOSETOITASWE WEREȄǼ0ETE#ONRAD

4HE.EURO 3ENSORY3YSTEMIN3PACE



STATIONINCOULDHAVEBEENDUETOAMISEVALUATIONBYTHE-IRCOSMONAUTSOFTHE ACTUALDISTANCEBETWEENTHETWOVEHICLES)HAVEAPERSONALINTERPRETATIONFORTHESE CHANGESINDISTANCEPERCEPTION;#L¦MENTAND2ESCHKE =)THINKTHATPERCEPTION OFABSOLUTEDISTANCESISALTEREDAFTERALONGEXPOSUREINACONʄNEDENVIRONMENTWHERE THEREISONLYASHORTDISTANCESIGHTING)TISKNOWNTHATDISTANCESBETWEENOBJECTSAND THEOBSERVERAREALTEREDWHENTHEREARENOOBJECTSWITHFAMILIARSIZES SUCHASTREES PEOPLE ORVEHICLES INTHEBACKGROUND4HISISTHECASEONTHE-OON INSIDEASPACE VEHICLE ORANYOTHERCONʄNEDPLACE0EOPLEWHOSPENDALONGTIMEINENCLOSEDCHAM BERS SUCHASDIVERSORSUBMARINERS HAVETROUBLEEVALUATINGDISTANCEWHENTHEYGET OUT&ORTHISREASON SUBMARINECREWMEMBERSARENOTALLOWEDTODRIVEIMMEDIATELY AFTERRETURNINGFROMLONGTOUROFDUTYINTHECONʄNEDSPACEOFASUBMARINE 4HEOBJECTSSEENINSIDETHE)33AREWITHINDISTANCESOFSEVERALCMTOAFEWMETERS WHEREASTHEOBJECTSOUTSIDE%ARTHORTHESTARS AREVERYFARAWAY4HEREISNOINTERME DIATE DISTANCE RANGE )T IS THEREFORE POSSIBLE THAT THE PERCEPTION OF THE DISTANCES TO OBJECTSISALTEREDINTHISINTERMEDIATERANGE %VENWHENOBJECTSOFAFAMILIARSIZEAREPRESENT OURPERCEPTIONOFDISTANCESISDIF FERENTWHENWELOOKINTHEVERTICALDIRECTION&OREXAMPLE WHENWELOOKDOWNFROM THETOPOFA MTALLBUILDING THEPEOPLEANDTHEVEHICLESBELOWLOOKNOTICEABLY SMALL"UTWHENWELOOKMȃDOWNȄTHESTREETATGROUNDLEVEL WEDONȀTCOMMENT ONHOWSMALLTHEPEOPLEANDVEHICLESLOOK4HEREASONISTHATWEHAVELEARNEDTHE ȃRULESȄFORSCALINGPEOPLEATADISTANCE BUTNOTFROMAHEIGHT)NTHEABSENCEOFAVERTI CALGRAVITATIONALREFERENCE THEPERCEPTIONOFDISTANCEMIGHTBEDISTORTEDINTHESAME WAYASWHENWELOOKDOWNORUP;#L¦MENTAND2ESCHKE = !NEXPERIMENTCURRENTLYINPROGRESSONBOARDTHE)33SEEMSTOINDICATETHATTHE ASTRONAUTS UNDERESTIMATE DISTANCE FOR THE INTERMEDIATE RANGE OF ǻ  M &IGURE !LSO THEPERCEPTIONOFDISTANCEINTHEVERTICALDIRECTION WHICHISCLEARLY OVERESTIMATEDONTHEGROUNDEG WHENONTOPOFABUILDING THEPEOPLEINTHESTREETS LOOKSMALL BECOMEASACCURATEASINTHEHORIZONTALDIRECTIONAFTERMONTHINORBIT)T ISUNCLEARIFTHESEILLUSIONSAREDIRECTEFFECTSOFREDUCEDGRAVITYONTHENEURO VESTIBULAR SYSTEM ASSEENINVESTIBULARPATIENTSON%ARTH;#L¦MENTETAL B =ORDUETO OTHERFACTORSOFTHESPACEENVIRONMENT SUCHASHIGHCONTRAST CONʄNEMENTTOCRAMPED QUARTERS AND THE ABSENCE OF KNOWN LANDMARKS IN THE CREWMEMBERȀS INTERMEDIATE SPACE.EVERTHELESS THESEERRORSINVISUALPERCEPTIONANDMISPERCEPTIONSOFSIZE DIS TANCEANDSHAPECOULDREPRESENTPOTENTIALLYSERIOUSPROBLEMS&OREXAMPLEIFACREW MEMBERDOESNOTACCURATELYGAUGETHEDISTANCEOFATARGET SUCHASADOCKINGPORTOR AN APPROACHING VEHICLE THEN THE SPEED OF THIS TARGET COULD ALSO BE MISEVALUATED )N ADDITION DISTURBANCES IN THE MENTAL REPRESENTATION OF OBJECTS AND THE SURROUND MAY INʅUENCE THE ABILITY OF ASTRONAUTS TO ACCURATELY PERFORM PERCEPTUAL MOTOR AND PERCEPTUAL COGNITIVETASKSSUCHASTHOSEINVOLVEDINROBOTICCONTROL

ȃ)NAPPEARANCES ITTOOKUSALONGTIMETOCONVINCEOURSELVESTHATSOMEOFTHECRATERSWHICHLOOKEDSOCLOSE WEREREALLYMUCHFARTHERAWAYȄǼ!LAN"EAN ȃ7HENWEWEREATTHE!,3%0SITE ITLOOKEDASIFWEWEREABOUTFEETWESTANDFEETNORTHOFTHEPOSI TIONOFTHE,-)TWASAPRETTYGOODLEVELSITE,ATERWHEN)GOTBACKTOTHE,-ANDLOOKEDBACK )NOTICED ITDIDNȀTLOOKASIFTHESITEWERETHATFARAWAY4HISWASTHECONTINUALPROBLEMWEHAD TRYINGTOJUDGEDIS TANCESȄǼ!LAN"EAN



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Figure 3.10. ESA Astronauts During a Training Session for the 3D-SPACE Experiment. This ISS Experiment Uses a Head-Mounted Visual Display, a Trackball, and a Digitizing Tablet. The Subject Is Presented with Depth-Related Visual Illusions, or 3D Objects That He Can Adjust So That They Look “Normal”, or Natural Scenes in Which He Has to Judge the Distance Between Identified Landmarks. The Digitizing Tablet Is Used for Neuropsychological Testing of Writing Horizontally and Vertically and Drawing Geometrical Figures with the Eyes Closed. (Credit ESA).

3USPICIONSARETHATDAYLIGHTISNOTBRIGHTONTHESURFACE-ARS4HESUNLIGHTON-ARS ISABOUTONE HALFOFTHEBRIGHTNESSOFTHATSEENON%ARTH4HESKYOFTHE2ED0LANET DOESNOTAPPEARBLUE BUTPINKDUETOSUSPENDEDDUST WHICHMEANSTHATTHESURFACEOF -ARSIS INFACT DARKERTHANWHATISEXPERIENCEDON%ARTH;/NLINESOURCEHTTPQUEST ARCNASAGOVMARSASKATMOSPHERE= !LSO ON -ARS THE TERRAIN MAY BE MORE SLOPED THAN THAT EXPLORED BY THE !POLLO ASTRONAUTS4HEASTRONAUTSMAYBETRAVERSINGAREASOFDEEPSHADOW POSSIBLYREQUIRING THEUSEOFLIGHTS3CIENTISTSAREALSOINVESTIGATINGOPTIONSFOR%6!SENSORYSUPPLEMEN TATION!LTHOUGHVIBROTACTILEANDELECTRODERMALCUEINGSYSTEMSHAVEBEENDEMONSTRATED INPATIENTS THESETECHNIQUESAPPEARENCUMBERINGANDIMPRACTICAL ANDREQUIRETHATTHE SUITALSOINCORPORATEACAPABLEINERTIALATTITUDEANDHEADINGREFERENCESYSTEM.IGHT VISION SENSOR IMAGERY AN ARTIʄCIAL HORIZON AND A NAVIGATION DISPLAY COULD ALSO BE INCORPORATEDINTOANADD ONEXTERNALHEADS UPDISPLAY;(IRMERAND#L¦MENT =  (EARING ȃ)NSPACE NOONECANHEARYOU;SCREAM=Ȅ4HISCLICH¦ WHICHISCOMMONLYUSEDIN SCIENCEʄCTIONMOVIES HASAPPARENTLYNOTATTRACTEDTHEINTERESTOFSCIENTISTSFORSTUDY INGHEARINGDURINGSPACEʅIGHT SINCEVERYLITTLEDATAISAVAILABLEYET 4HE)33ISANOISYPLACE4OBETTERCHARACTERIZETHEACOUSTICENVIRONMENT ASOUND MEASUREMENTSURVEYISPERFORMEDONCEEVERYMONTHSTOMEASURETHEACOUSTICSPEC TRALLEVELSATSPECIʄEDLOCATIONS!NACOUSTICENGINEERINGEVALUATIONISPERFORMEDTO DIAGNOSEACOUSTICABNORMALITIES INVESTIGATECREWCOMPLAINTS ANDEVALUATEEFFECTIVE NESSOFNEWLYINSTALLEDNOISEREDUCTIONMEASURES.OISEEXPOSURELEVELSAREMEASURED BYCREW WORNDOSIMETERSCOMPLEMENTEDBYDOSIMETERSDEPLOYEDATʄXEDLOCATIONSTO DETERMINEWORK SLEEP AND HNOISEEXPOSURELEVELSWITHAMICROPHONEONTHESHIRT

4HE.EURO 3ENSORY3YSTEMIN3PACE



COLLAR 2ECENTDATAINDICATETHATNOISELEVELSONTHE)33 EVENDURINGSLEEPPERIODS CANAVERAGEMORETHAND"! ANDTHATTHERECORDINGSHAVEȃMAXEDOUTȄATOVER D"!DURINGSCHEDULEDSLEEPINTERVALS 3EVERALASPECTSOFSPACEʅIGHTCANHAVEANIMPACTONHEARINGCAPABILITYA LIFE SUPPORTEQUIPMENTISCONTINUOUSLYRUNNINGRANGINGFROMD"!FORTHEAIRCONDI TIONINGTOD"!FORSOMEVENTRELIEFVALVES ANDTHENOISEREVERBERATESTHROUGHTHE SPACECRAFTȀSSTRUCTUREB ASTRONAUTSSPEND HADAYINTHEOFʄCE ALWAYSCLOSETO NOISESOURCESANDC THEREISNOPRIVACY WITHACONSTANTINTERACTIONWITHOTHERCREW MEMBERS4HUSQUIETNESSPERIODSSUCHASON%ARTHDONOTEXISTEARPLUGSCANREDUCE NOISEBUTNOTVIBRATIONS 3PACEʅIGHT RAISES A SPECTRUM OF NOISE QUESTIONS ITS EFFECT ON PERCEPTION AND PERFORMANCE ADAPTATIONEFFECTS THEFATIGUINGANDANNOYINGASPECTSOFNOISE ANDINDI VIDUAL SENSITIVITY DIFFERENCES 4HE DEGREE TO WHICH NOISE AND ENVIRONMENTAL DISTURBANCES AFFECT SLEEP DURING SPACEʅIGHT MISSIONS REMAINS TO BE DETERMINED "ECAUSECERTAINMINIMUMNOISELEVELSAREALWAYSPRESENT SPACEʅIGHTPOTENTIALLYCON STITUTES A MORE STRESSFUL NOISE ENVIRONMENT THAN A SIMPLE CONSIDERATION OF DECIBEL LEVELSWOULDIMPLY&IGURE 

Figure 3.11. Canadian Space Agency Astronaut Robert Thirsk Works with a Sound Level Meter for an Acoustic Survey in the Destiny Laboratory of the ISS. Note the Procedure Documents on His Lap. (Credit NASA).

4HE THRESHOLD FOR HEARING IS DEʄNED AS  D"! CORRESPONDING TO CORRESPONDS TO  OF A TMOSPHERICPRESSUREBILLIONTH 4HETHRESHOLDFORPAINISOFATMOSPHERICPRESSURE ORAPPROXI MATELYD"!&ORCOMPARISON ACIRCULARSAWCREATESNOISELEVELSFROMTOD"!%VENWHATWECALL ȃSILENCEȄON%ARTHISINFACTABACKGROUNDNOISEOFABOUTD"!





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!LTHOUGHVERYSTRINGENTNOISEREQUIREMENTSFOR)33RESULTINANOISEENVIRONMENT COMPARABLETOHOMEANDOFʄCE INTELLIGIBILITYOFHEARINGASNOISEINCREASESMAYVARY ACROSSINDIVIDUALS&OREXAMPLE ITISKNOWNTHATBOTHTHELACKOFLANGUAGEPROʄCIENCY ANDTHEREVERBERANCEINAROOMIMPAIRHEARING4HEPERFORMANCEOFANATIVE%NGLISH SPEAKER ON BOARD THE )33 AT  D"! THEREFORE MUST TO BE COMPARED WITH THAT OF A NON NATIVE%NGLISHSPEAKERATD"!
)NADDITION LOWNOISELEVELSCANALSOBEANNOY INGANDAFFECTINDIVIDUALANDGROUPCOMMUNICATION BEHAVIOR 4HEINVESTIGATIONOFHEARINGINASTRONAUTSISDIFʄCULTTOCONDUCTDURINGSPACEʅIGHT BECAUSECLASSICALHEARINGASSESSMENTTECHNIQUESDONOTWORKINTHENOISYENVIRONMENTS OFTENFOUNDINSPACECRAFTNOSOUNDPROOFLABORATORY "ECAUSECREWMEMBERSAREATRISK FORHEARINGLOSSDUETONOISELEVELSOFTENENCOUNTEREDDURINGSPACEʅIGHT TECHNIQUES ANDINVESTIGATIONTOTRACKTHISLOSSARENEEDEDDURINGANDAFTERTHEMISSION !UDITORYBRAINSTEMRESPONSERECORDINGSWEREINVESTIGATEDDURINGSHUTTLEʅIGHTS .OSIGNIʄCANTDIFFERENCESWEREOBSERVEDBETWEENMEANLATENCYVALUESFORANYPOTEN TIALONTHEGROUNDORDURINGʅIGHT SUGGESTINGTHATTHEAUDITORYFUNCTIONISNOTALTERED INMICROGRAVITY;4HORNTONETAL =!NOTHEREXPERIMENTPERFORMEDON-IRSHOWED THATTHELOCALIZATIONOFASOUNDSOURCEINMICROGRAVITYWASWITHINTHESAMERANGEAS ON%ARTH IE BETWEENmANDm3INCETHEFACULTYOFLOCALIZINGSOUNDSOURCESDEPENDS ONNORMALBINAURALHEARING ITWASCONCLUDEDFROMTHISSTUDYTHATHEARINGWASNOT ALTEREDINCOSMONAUTS  3MELLANDTASTE )TISWELLKNOWNTHATDURINGSPACEʅIGHT ASTRONAUTSASKFORMORESPICESANDCONDI MENTSTOADDTASTETOTHEPREPAREDFOOD$IMINISHEDSENSITIVITYTOTASTEANDODORCOULD RESULTFROMTHEPASSIVENASALCONGESTIONREPORTEDINCONJUNCTIONWITHTHEHEADWARD SHIFT OF ʅUID 4ASTE PARTICULARLY THE NON VOLATILE COMPONENT MEDIATED BY THE TASTE BUDS MAY BE SUSCEPTIBLE TO THRESHOLD SHIFTS IN MICROGRAVITY BECAUSE OF A REDUCED MECHANICALSTIMULATIONASARESULTOFCHANGESINTHECONVECTIONPROCESS %VALUATION OF OLFACTORY RECOGNITION USING PAPER IMPREGNATED WITH LEMON MINT VANILLA ORDISTILLEDWATER ANDTASTERECOGNITIONUSINGSOLUTIONOFSOLUTIONSOFSUCROSE UREA SODIUMCHLORIDE ANDCITRICACID DEMONSTRATEDNOSUBJECTIVECHANGESINSMELLOR TASTEFUNCTIONPOSTʅIGHT(OWEVER THEREWERELARGEDIFFERENCESAMONGINDIVIDUALS3OME OFTHEMCOULDHAVEBEENDUETOTHEREMINISCENCEOFSPACEMOTIONSICKNESSSYMPTOMS
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Figure 3.12. An Astronaut with the Feet Attached to the Floor of the Space Shuttle and Placed in Darkness Using an Occluding Goggle Is Instructed to Maintain an “Upright” Posture on Flight Day Two. In the Absence of Gravitational and Visual Inputs, His Body Is Tilted Forward, Suggesting a Recalibration of the Proprioceptive Inputs from the Ankle Joint. (Credit NASA).

THE SKIN IF THE OBJECT IS PLACED UPON A SUPPORTED LIMB 7EIGHT CAN ALSO BE JUDGED ACTIVELY IFTHEOBJECTISHELDAGAINSTTHEFORCEOFGRAVITYBYTHEMUSCULAREFFORT ORIS REPEATEDLYLIFTED-ASSCANONLYBEJUDGEDACTIVELY DERIVEDFROMTHEFORCEREQUIREDTO PRODUCEAGIVENACCELERATION ORFROMTHEACCELERATIONPRODUCEDBYIMPARTINGAGIVEN FORCE4HUS ACTIVEWEIGHTPERCEPTIONUSUALLYINCLUDESMASSPERCEPTION)TISTHEREFORE DIFʄCULTTOINVESTIGATEWEIGHTWITHOUTMASSDURINGACTIVEMOVEMENT EXCEPTINWEIGHT LESSNESS5SINGBALLSOFVARIOUSMASSESTHATTHEASTRONAUTSSHOOKUPANDDOWNMOVING THEIR ARMS IT WAS FOUND THAT THE PROCESS OF DISCRIMINATING THE MASS OF OBJECTS IN MICROGRAVITY WAS LESS ACCURATE THAN IN NORMAL GRAVITY 7EIGHT DISCRIMINATION WAS IMPAIREDFORORDAYSPOSTʅIGHT WHILECREWMEMBERSFELTTHEIRBODIESANDOTHER OBJECTSTOBEEXTRAHEAVY4HEIMPAIRMENTIN ʅIGHTWASPARTLYDUETOTHELOSSOFWEIGHT INFORMATIONAREDUCTIONINTHEPRESSURESTIMULATION ANDPROBABLYALSOTOINCOMPLETE ADAPTATIONTOMICROGRAVITY4HEINCREASEINAPPARENTHEAVINESSOFOBJECTSREPORTEDFOR STATIC WEIGHT JUDGMENT AFTER THE ʅIGHT SUGGESTS THAT SOME CENTRAL RE SCALING OF THE STATICPRESSURESYSTEMSHADOCCURRED;2OSSETAL =

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(UMANFACTORSTUDIES AFTERINVESTIGATINGPHOTOGRAPHSTAKENDURING3KYLABMISSIONS HAVELEDTOTHE.EUTRAL"ODY0OSTUREMODEL&IGURE 4HISMODELISCHARACTERIZED BYAFORWARDTILTOFTHEHEADWITHTHELINEOFSIGHTmLOWERTHANTHEBODY CENTERED HORIZONTAL REFERENCE SHOULDERS UP LIKE A SHRUG AND ARMS AʅOAT UP AND FORWARD WITHHANDSCHESTHIGH 2ECENTINVESTIGATIONS TAKINGINTOACCOUNTBODYSIZE GENDER ANDMISSIONDURATION SUGGEST HOWEVER THATTHENEUTRALBODYPOSTUREMODELISTOOGENERALIZED ANDSHOULD BEMODIʄEDWITHADDITIONALDATATOPROVIDEMOREREPRESENTATIVESPACEʅIGHTCREWPOS TURES(OWEVER ITISUNCLEARHOWTHEDIRECTIONOFTHELINEOFSIGHTHASBEENEVALUATED FROMTHE3KYLABPHOTOGRAPHS!LSO THEDOWNWARDDEVIATIONOFGAZEINMICROGRAVITY IN THIS MODEL IS IN CONTRADICTION WITH THE RESULTS OF SEVERAL SPACE EXPERIMENTS THAT ACTUALLYMEASUREDTHEEYEDEVIATIONDURINGSPACEʅIGHTSEE3ECTION 

Figure 3.13. The Neutral Body Posture and the Rest Position of Foot, Leg, Hip, Elbow, Shoulder, and Neck Joints in Microgravity, as Well as the Direction of the Line of Sight, Were Modeled Based on the Photographs of Skylab Astronauts. (Adapted from NASA [1995]. Credit NASA).

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Figure 3.14. Subjects’ Ability to Stand as Still as Possible Is Investigated Using a Computerized Force Platform Inside a Visual Booth. The Platform and the Booth Are Designed to Isolate the Multiple Sensory Information Used in Balance – Visual, Vestibular, and Proprioceptive. An Equilibrium Score Is Calculated from Various Sensory Tests, E.g., with the Eyes Open or Closed, the Platform Still or Translating, the Visual Environment Still or Tilting. The Graph Compares the Data for 13 Crewmembers Before (Pre) and After Landing (in Hours Following Shuttle Wheel Stop), Compared with a Large Normative Database. A Few Hours After Landing, the Average Returning Crewmember Was Below the Limit of Clinical Normality (Dashed Line). Preflight Stability Levels Were Achieved by 8 Days After Landing, Following a Double Exponential Time Course. (Adapted from Paloski et al. [1993]).

TRAUMATICINJURIESTOTHEINNEREARCANSEVERELYINʅUENCEQUALITYOFLIFE&ALLSARETHE LEADINGCAUSEOFINJURY RELATEDDEATHSINTHEELDERLYANDTHESENUMBERSCONTINUETO INCREASE)NNEREARDISORDERSARETHOUGHTTOACCOUNTFORǻOFFALLSAMONGSENIOR CITIZENS #URRENTLY HUMAN SPACEʅIGHT IS THE ONLY MEANS AVAILABLE FOR STUDYING THE RESPONSETOSUSTAINEDLOSSANDRECOVERYOFINNEREARINFORMATION#OMPARISONBETWEEN DATAFROMASTRONAUT SUBJECTSANDSIMILARDATAFROMPATIENTSANDELDERLYSUBJECTSDEM ONSTRATESSIMILARITIESBETWEENTHESEBALANCEDISORDERS/NESENSIBLEDIFFERENCEISTHAT THE POSTURE PROBLEMS RECOVER IN A FEW DAYS FOR THE ASTRONAUTS WHEREAS IT CAN TAKE WEEKSINTHEPATIENTS SOMEOFWHONEVERRECOVER)TISHOPEDTHATABETTERUNDERSTAND ING OF THE STRATEGIES USED DURING THE RECOVERY PROCESS IN THE ASTRONAUTS AND OF THE PLASTICITYOFTHISSYSTEMINGENERAL WILLHELPTOIMPROVEREHABILITATIONTREATMENTSFOR PATIENTSWITHBALANCEDISORDERSON%ARTH 

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 $AN"ARRY ANASTRONAUTOFTHE343 3HUTTLEMISSION GOTSTRANDEDINTHEMIDDLEOFAN)33MODULE WITH THE HELP OF TWO FELLOW CREWMEMBERS (E THEN TRIED TO KICK HIMSELF OVER TO THE WALL (E RECALLED LATER ȃ7HEN)REACHEDOUTANARM MYBODYMOVEDBACKANDMYCENTERREMAINEDINTHEMIDDLEOFTHEROOM )INSTINCTIVELYTRIEDMOVINGFAST THENSLOW ANDTHENBICYCLEDMYLEGS.ONEOFITHELPED)JUSTHADTOWAIT FORTHEAIRCURRENTSTODRIFTMETOTHEWALL3NEEZINGANDSPITTINGDIDNȀTDOMUCHGOODEITHER/NTHEOTHER HAND THROWINGCLOTHINGASFASTAS)COULDPRODUCEDENOUGHREACTIONTOSENDMETOTHEOPPOSITEWALL

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;0OZZOETAL =!FTERSPACEʅIGHT HOWEVER CHANGESHAVEBEENDOCUMENTEDIN BOTH HEAD TRUNK AND LOWER LIMB PATTERNS OF COORDINATION "LOOMBERG ET AL ;= REPORTEDCHANGESINHEADPITCHVARIABILITY AREDUCTIONOFCOHERENCEBETWEENTHETRUNK ANDCOMPENSATORYPITCHHEADMOVEMENTS ANDSELFREPORTSFROMCREWMEMBERSTHAT INDICATED AN INCREASED INCIDENCE OF OSCILLOPSIA THE ILLUSION OF A VISUAL SURROUND MOTION DURINGPOSTʅIGHTTREADMILLWALKING&IGURE !NUMBEROFCHARACTERISTICS OFWALKINGALSOAPPEARTOBECHANGEDAFTERSPACEʅIGHT&OREXAMPLE DURINGTHECON TACTPHASEOFWALKING THEFOOTȃTHRUSTSȄONTOTHESUPPORTSURFACEWITHAGREATERFORCE THANTHATOBSERVEDBEFOREʅIGHT 4HEALTERATIONSINLOCOMOTIONSEENAFTERSPACEʅIGHTRAISESOMECONCERNABOUTTHE CREWCAPABILITYFORUNAIDEDEGRESSFROMTHESPACESHUTTLEORTHE3OYUZINACASEOF EMERGENCY !S DISCUSSED EARLIER MANY CREWMEMBERS EXPERIENCE MARKED VERTIGO WHENMAKINGHEADMOVEMENTSDURINGRE ENTRY LANDING ANDAFTERWARDS4HISVERTIGO COULD BE A MAJOR OBSTACLE TO SUCCESSFUL EGRESS IF VISION WERE IMPAIRED AS WITH A SMOKE ʄLLEDCABIN!NINTERESTINGINVESTIGATIONWASPERFORMEDBY"LOOMBERGETAL ;= INWHICHTHEABILITYFORCREWMEMBERSTOREPEATAPREVIOUSLYSEENTRAJECTORY WITHOUTVISIONWASEXAMINED7HENATTEMPTINGTOWALKATRIANGULARPATHAFTERʅIGHT BLINDFOLDEDSUBJECTSSHOWEDBOTHUNDER ANDOVER ESTIMATIONSOFTHEDISTANCESWALKED BUT A CORRECT ESTIMATION OF THE ANGLE TURNED 4HESE RESULTS SUGGEST A DIFʄCULTY FOR RECONSTRUCTING MOTION CUES FROM THE OTOLITHS BUT NOT FROM THE SEMICIRCULAR CANALS (OWEVER THECHANGESFOUNDCOULDALSOBERELATEDTOTHELOWERWALKINGVELOCITYDURING POSTʅIGHT TESTING 4HESE RESULTS IMPLY THAT MECHANISMS LIKE COMPUTING SELF DISPLACEMENTANDUPDATINGSPATIALINFORMATIONBOTHOFWHICHBEINGALSOCALLEDNAVI GATION AREDISTURBEDBYSPACEʅIGHTANDHAVETOBEREACQUIREDAFTERRETURNTO%ARTH !POLLOASTRONAUTSFELLFREQUENTLYONTHESURFACEOFTHE-OON)NPARTICULAR THEHIGH ANDREARWARDCENTEROFGRAVITYOFTHE!POLLOSUITINʅUENCEDUPSLOPEWALKING ANDTHE STIFFNESSOFTHEINʅATEDSUITSTRONGLYINʅUENCEDGAIT ANDMADEITIMPOSSIBLETOSQUAT TO RETRIEVE DROPPED OBJECTS .EW REQUIREMENTS FOR SUIT CENTER OF GRAVITY AND BIOMECHANICALPROPERTIESOFVARIOUSMOTIONSONTHE-ARTIANSURFACEMUSTBEDEʄNED

Figure 3.15. Head Movements Along the Fore-Aft (X), Lateral (Y), and Vertical (Z) Directions in One Crewmember During Walking on a Treadmill Before Spaceflight and on the Day Following Landing of the Space Shuttle. (Adapted from Bloomberg et al. [1999]).

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)TISHIGHLYDESIRABLETOREDUCETHEINCIDENCEOFFALLSNOTONLYTOREDUCETHERESIDUAL MEDICALRISKS BUTALSOBECAUSEFALLSCUTINTO%6!EFʄCIENCY ANDREGAININGONEȀSFEET REQUIRESPHYSICALEFFORT/NCETIRED ANASTRONAUTMIGHTBEEXPECTEDTOFALLMOREFRE QUENTLYǻAPHENOMENONVERYFAMILIARTOANYBEGINNERSKIER0REʅIGHTSENSORIMOTOR LOCOMOTIONTRAININGMIGHTHELPTOEXPANDTHEREPERTOIREOFAUTOMATICMOTORRESPONSES TOLOCOMOTORDISTURBANCES;0ALOSKIETAL = 

"ODYMOVEMENT

/N%ARTHȀSSURFACE GRAVITYSIGNIʄCANTLYAFFECTSMOSTOFOURMOTORBEHAVIOR)THAS BEENESTIMATEDTHATABOUTOFOURMUSCULATUREISDEVOTEDTOOPPOSINGGRAVITY&OR EXAMPLE WHENMAKINGLIMBMOVEMENTSDURINGSTATICBALANCE ANTICIPATORYINNERVA TIONSOFLEGMUSCLESCOMPENSATEFORTHEIMPENDINGREACTIONTORQUESANDTHECHANGES IN LOCATION AND PROJECTION OF THE CENTER OF MASS ASSOCIATED WITH THESE MOVEMENTS 3IMILARPATTERNSOFANTICIPATORYCOMPENSATIONSARESEENIN ʅIGHT ALTHOUGHTHEYARE FUNCTIONALLYUNNECESSARY!LSO RAPIDLYBENDINGTHETRUNKFORWARDANDBACKWARDAT THEWAISTISACCOMPANIEDON%ARTHBYBACKWARDANDFORWARDDISPLACEMENTSOFHIPS ANDKNEESTOMAINTAINBALANCE4HESAMECOMPENSATORYMOVEMENTSOFHIPSANDKNEES AREMADEINWEIGHTLESSNESS"ECAUSETHEEFFECTIVEGRAVITYTORQUESAREABSENTDURING SPACEʅIGHT THEINNERVATIONSNECESSARYTOACHIEVETHESESYNERGIESINWEIGHTLESSNESS AREDIFFERENTFROMTHOSENEEDEDON%ARTH#ONSEQUENTLY THESEIN ʅIGHTMOVEMENTS MUSTREʅECTREORGANIZEDPATTERNSOFMUSCLEACTIVATION $URING THE ʄRST SPACE EXPERIMENTS IN WHICH ) PARTICIPATED IN  WHICH WERE CONDUCTEDONBOARDTHE3ALYUT SPACESTATION WEFOUNDTHATDORSI ʅEXORMUSCLES EG THE4IBIALISANTERIORLEGMUSCLE ASSUMEALARGERROLEINSPACETHANON%ARTHIN REGULATINGTHEORIENTATIONOFTHEINDIVIDUALRELATIVETOHISHERSUPPORT4HISISINCON TRASTWITHTHEGENERALUSEOFMUSCLEEXTENSORSON%ARTH WHICHAREUSEDTOCOUNTERACT GRAVITY4HISTRANSFEROFMOTORSTRATEGIESFROMONEMUSCLEGROUPTOANOTHEREXPLAINS THE FORWARD TILTED POSTURE OF CREWMEMBERS PLACED IN DARKNESS WHEN INSTRUCTED TO MAINTAINAPOSTUREPERPENDICULARTOTHEFOOTSUPPORTSEE&IGURE  5SINGASIMPLEBALLCATCHINGEXPERIMENTINWEIGHTLESSNESS ITHASBEENELEGANTLY SHOWNTHATTHECENTRALNERVOUSSYSTEMUSESANINTERNALESTIMATEOFGRAVITYINTHEPLAN NINGANDEXECUTIONOFMOVEMENTS$URINGTHEACTOFCATCHINGABALLON%ARTH THEBRAIN ESTIMATESTHETRAJECTORYOFTHEBALL ACCURATELYTAKINGINTOACCOUNTITSDOWNWARDACCEL ERATIONDUETOGRAVITY)NSPACE ASEATEDASTRONAUTWASREQUIREDTOCATCHABALLTRAVEL INGATACONSTANTVELOCITY INCONTRASTTOTHECONSTANTACCELERATIONTHATWOULDOCCURON %ARTH&IGURE 4HEABILITYTOANTICIPATEANDPREDICTISONEOFTHENERVOUSSYS TEMȀSBASICFUNCTIONS7HENWECATCHABALL THEBRAINDOESNOTWAITFORITTOTOUCHTHE HANDBEFORESTIMULATINGARMʅEXORMUSCLECONTRACTIONTOCOMPENSATEFORTHEIMPACT !BOUTONETHIRDOFASECONDBEFOREIMPACT THEBRAINELICITSJUSTTHERIGHTAMOUNTOF CONTRACTIONTOCOUNTERACTTHEFORCEEXERTED WHICHITSELFDEPENDSONTHEWEIGHTOFTHE OBJECTCOMBINEDWITHTHEACCELERATIONOFITSFALL4HEEXPERIMENTLEDTOTHECONCLUSION THATTHEBRAINWORKSBYANTICIPATINGTHEEFFECTSOFGRAVITYONTHEBALLRATHERTHANBY MAKINGDIRECTMEASUREMENTSOFITSACCELERATION4HISANTICIPATIONABILITYREMAINSEVEN INCONDITIONSOFWEIGHTLESSNESS4HANKSTOCHILDHOODEXPERIENCE THEBRAINPOSSESSES INTERNALMODELSOFTHEGRAVITYLAWSGOVERNINGTHEBEHAVIOROFAFALLINGOBJECT AND PERHAPSMOREGENERALLY .EWTONȀSLAWOFMECHANICS7ESEEHERETHEBEGINNINGSOF

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Figure 3.16. Ball Catching Experiment During the Neurolab STS-90 Mission. A Ball Was Thrown at the Subject at a Constant Velocity. The Trajectory of the Subject’s Arm and the Activity of His Forearm Muscles Were Recorded as He Was Trying to Catch the Ball. (Credit NASA).

ANADAPTATIONTONEWLAWS!LONGERPERIODINWEIGHTLESSʅIGHTWOULDNOWBENEEDED TOASSESSHOWSUCHANADAPTATIONMIGHTDEVELOP;-C)NTYREETAL = ,IKEWISE THE ANALYSIS OF ASTRONAUTSȀ WRITING OR DRAWING SHOWED THAT SUCH ʄNE MOVEMENTS ARE NOT ALTERED IN MICROGRAVITY 7HEN COSMONAUTS WERE ASKED TO DRAW ȃHORIZONTALȄ ELLIPSES IN THE AIR WITHOUT THE AID OF VISION RESULTS INDICATED MINIMAL CHANGESASAFUNCTIONOFMICROGRAVITY SUGGESTINGTHATTHEBODYEGOCENTRIC REFERENCE SYSTEMWASNOTDISTURBED4HESUBJECTSWERECAPABLEOFMAINTAININGASENSEOFVERTI CALITYDESPITEDISAPPEARANCEOFTHEMAINFACTORCONTRIBUTINGTOVERTICALITYON%ARTH IE THEGRAVITATIONALFORCE;'URʄNKELETAL =(OWEVER BENDINGTHEHEADOVERTHE TRUNKCAUSESTHECOSMONAUTSARMMOVEMENTPATTERNTOBEMOREALIGNEDWITHTHEHEAD VERTICALAXIS INDICATINGTHATTHEHEADAXISCOULDALSOBEUSEDASAREFERENCEFRAME 

%YEMOVEMENT

%YE MOVEMENT IS PROBABLY THE RESPONSE OF THE VESTIBULAR SYSTEM THAT HAS BEEN THE MOSTSTUDIEDDURINGSPACEʅIGHT&ORSEVERALDECADES THESTUDYOFEYEMOVEMENTSHAS BEENASOURCEOFVALUABLEINFORMATIONTOBOTHBASICSCIENTISTSANDCLINICIANS4HESIN GULARVALUEOFSTUDYINGEYEMOVEMENTSSTEMSFROMTHEFACTTHATTHEYARERESTRICTEDTO



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ROTATIONS IN THREE PLANES AND THE EYEBALL OFFERS VERY LITTLE INERTIA TO THE EYE 4HIS FACILITATES ACCURATE MEASUREMENT FOR EXAMPLE USING VIDEO EYE RECORDING IN NEAR INFRAREDLIGHT APREREQUISITEFORQUANTITATIVEANALYSIS %YE MOVEMENTS MUST CONTINUOUSLY COMPENSATE FOR HEAD MOVEMENTS SO THAT THE IMAGEOFTHEWORLDISHELDFAIRLYSTEADYONTHERETINA ANDTHUSAPPEARSCLEARANDSTA TIONARY$URINGHEADMOVEMENTS THEVESTIBULARAPPARATUSMEASURESHEADVELOCITYAND RELAYSTHISINFORMATIONTOTHOSECENTERSCONTROLLINGEYEPOSITIONTOGENERATECOMPENSA TORY EYE MOVEMENTS THIS REʅEX BEHAVIOR ENSURES THAT VISION IS NOT BLURRED 7HEN PERFORMEDINDARKNESS THISLEADSTOAPATTERNOFRHYTHMICEYEMOVEMENTSKNOWNAS NYSTAGMUS CONSISTINGOFSLOWPHASESINTHEDIRECTIONOPPOSITETOTHEHEADANDFAST PHASESTHATBRINGTHEEYEBACKWHENITREACHESTHEEXTREMEOFITSTRAVEL4HENYSTAG MUSRESPONSETOARAPIDHEADMOVEMENTOUTLASTSTHECHANGESINSIGNALSINTHESEMICIR CULARCANALS THROUGHTHEACTIVATIONOFAVELOCITYSTORAGEMECHANISMLOCATEDINTHE BRAINSTEM 4HISSO CALLEDȃVESTIBULO OCULARREʅEXȄHASBEENSTUDIEDSYSTEMATICALLYINORBITAL ʅIGHT BOTHDURINGACTIVEVOLUNTARY ANDPASSIVEMOVEMENTSOFTHEHEAD;#L¦MENT =7ITHMYCO INVESTIGATORS WEWERETHEʄRSTTOREPORTTHATTHEAMPLITUDEOFVER TICAL EYE MOVEMENTS WAS DECREASED DURING THE ʄRST  DAYS OF WEIGHTLESSNESS COM PARED TO NORMAL VALUE ON %ARTH BUT NOT THE HORIZONTAL EYE MOVEMENTS )N THIS EXPERIMENT THE EYE MOVEMENTS OF AN ASTRONAUT WERE RECORDED WHEN HE VOLUNTARY MOVEDHISHEADWHILEEITHERʄXATINGAVISUALTARGETORIMAGININGTHATTARGETINDARK NESS$URINGTHEʄRSTFEWDAYSINORBIT THEVESTIBULO OCULARREʅEXWASLESSEFʄCIENTIN STABILIZINGTHEVISUALIMAGE4HISRESPONSERECOVEREDQUICKLY BUTSUBSEQUENTINVESTI GATIONSCONʄRMEDTHATAFTERSPACEʅIGHT THEPATTERNOFEYEANDHEADMOVEMENTSWAS AGAINSIGNIʄCANTLYALTEREDWHENSUBJECTSMOVEDTHEIRHEADINANATTEMPTTOʄXATEA VISUALTARGET&IGURE  0ROBLEMS IN HAND EYE COORDINATION AND BLURRINESS OF THE VISUAL SCENE WHEN RE ENTERINGINNORMALGRAVITYHAVEALSOBEENREPORTEDAFTERLONG DURATIONMISSIONS 4RACKINGOFMOVINGVISUALTARGETSSEEMSTOBEALTERED ESPECIALLYINTHEVERTICALDIREC TION!FTERLANDING SUBJECTSHAVEDIFʄCULTIESFOLLOWINGAVERTICALLYMOVINGVISUALDOT 7HENTHETARGETMOVESUP THEEYESTRYTOCATCH UPTHEVISUALTARGETWITHFASTSACCADES RATHERTHANSMOOTHPURSUIT4HEVESTIBULARNUCLEILOCATEDINTHEBRAINSTEMAREPARTOF ASYSTEMTHATALLOWSONETOʄXTHEGAZEONASTATIONARYTARGETDURINGVOLUNTARYHEAD MOTIONSASWELLASTOTRACKMOVINGTARGETS4HISSYSTEMAPPEARSTOBEDISTURBEDDURING SPACEʅIGHT PRESUMABLYASACONSEQUENCEOFALTEREDVESTIBULARRECEPTORFUNCTIONDUE TOTHEABSENCEOFGRAVITY4HESEDEʄCITSMIGHTPOSEAPROBLEMFORPILOTINGTASKSDURING LANDINGON-ARS /NEPROBLEMINSTUDYINGEYEMOVEMENTSBYASKINGSUBJECTSTOPERFORMVOLUNTARY HEADMOVEMENTSISTHATTHE#.3ISȃAWAREȄOFTHEMOVEMENTTOBEPERFORMED!COPY OFTHEMOTORCOMMANDTHESO CALLEDEFFERENCECOPY ISPRESUMABLYSENTTOTHEEYE HEADCOORDINATIONCONTROLSYSTEM ANDTHISHELPSTOACHIEVETHEADEQUATE COMPENSA TORYEYEMOVEMENTS&ORTHISREASON SCIENTISTSALSOUSEPASSIVEROTATIONGENERATEDBY SERVO CONTROLLEDROTATINGCHAIRORSLEDTOGENERATEUNPREDICTABLEINERTIALSTIMULATIONOF THEVESTIBULARSYSTEMANDTOSTUDYTHERESULTINGRESPONSES3EVERALOFTHESEDEVICES HAVEʅOWNONBOARDTHE3PACELAB)N A MLINEARSLEDGENERATEDSINUSOIDAL OSCILLATIONSINSUBJECTSSITTINGEITHERFACINGTHETRACK ORPERPENDICULARTOIT ORLYING

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Figure 3.17. The Ability to Maintain Visual Fixation on Targets While Turning the Head Is Diminished Immediately After Landing. Compared with the Preflight Response, the Head Movement Is Delayed and Its Amplitude Is Reduced Postflight (1). As a Consequence, the Vestibulo-Ocular Reflex Is Initiated at an Inappropriate Time (2), Pulling Gaze from Target (3). Large Eye Saccades (4) Are Then Required to Direct Gaze Back on Target (5).

ON THEIR BACK 4HE PEAK LINEAR ACCELERATION WAS  G !BSOLUTE THRESHOLDS FOR THE PERCEPTIONOFLINEARACCELERATIONIN ʅIGHTANDPOSTʅIGHTWEREFOUNDTOBEELEVATEDIN SOMEASTRONAUTSANDLOWEREDINOTHERSFORSOMEAXES RELATIVETOGROUND BASEDCON TROLS!NOTHERMEASUREOFLINEARACCELERATIONSENSITIVITY THETIMEELAPSEDFROMACCEL ERATION ONSET TO REPORTS OF SELF MOTION WHICH VARIES INVERSELY WITH MAGNITUDE OF ACCELERATION HAVEBEENMORECONSISTENT2ESULTSINDICATEANELEVATIONOFTHESENSITIV ITY WHEN LINEAR ACCELERATIONS ARE EXERTED ALONG THE BODY LONGITUDINAL AXIS AND A DECREASEINSENSITIVITYFORTHEOTHERAXES)TIS HOWEVER DIFʄCULTTORULEOUTACONTRIBU TIONOFTHESOMATO SENSORYSENSATIONINTHESERESULTS )N AROTATINGCHAIRʅEWONBOARDTHE3PACELAB)-, MISSION ALLOWINGTHE EVALUATIONOFTHEVESTIBULO OCULARREʅEXEVOKEDBYPASSIVEROTATIONOFFOURCREWMEM BERS ABOUT THE YAW OR PITCH OR ROLL AXIS DURING THE COURSE OF A  DAY SPACEʅIGHT 2ESULTS SHOWED THAT THE RESPONSES GENERATED BY ROTATION IN PITCH AND ROLL WERE THE MOSTAFFECTEDINSPACE -ORERECENTLY IN AHUMAN RATEDCENTRIFUGEʅEWONTHE.EUROLABMISSION IN WHICH CREWMEMBERS WERE BOTH EXPOSED TO ANGULAR AND LINEAR ACCELERATION SEE &IGURE /NEOBJECTIVEOFTHISEXPERIMENTWASTOSTUDYTHEADAPTATIONOFTHE#.3 BY MEASURING THE EYE MOVEMENTS IN RESPONSE TO ANGULAR AND LINEAR ACCELERATION IN SPACE%YEROTATIONSCANCOMPENSATEFORBOTHTHEROTATIONALANDTHETRANSLATIONALCOM PONENTSOFHEADMOTION/NTHE%ARTHȀSSURFACE TWOMAJORSOURCESOFLINEARACCELERA TIONARENORMALLYENCOUNTERED/NEISRELATEDTOTHE%ARTHȀSGRAVITYTHEGRAVITATIONAL



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FORCEPULLSTHEBODYTOWARDTHECENTEROFTHE%ARTH ANDTHEBODYOPPOSESTHISFORCETO MAINTAINANUPRIGHTSTANDINGPOSTURE4HEOTHERSOURCESOFLINEARACCELERATIONARISEIN THE SIDE TO SIDE UP DOWN OR FRONT BACK TRANSLATIONS OF THE HEAD WHICH COMMONLY OCCURDURINGWALKINGORRUNNING ANDFROMTHECENTRIFUGALFORCESENSEDWHENTURNING ORGOINGAROUNDCORNERS4HEBODYRESPONDSBYTENDINGTOALIGNTHELONGITUDINALBODY AXISWITHTHERESULTANTLINEARACCELERATIONVECTOR0UTINSIMPLETERMS WEHAVETOEXERT ANUPWARDFORCESUCHASTOBALANCEGRAVITYWHENSTANDINGUPRIGHTANDTOTILTINTOTHE DIRECTIONOFTHETURNWHENINMOTION!SMENTIONEDABOVE INMICROGRAVITY THEOTO LITHSARENOTSTIMULATEDBYHEADTILT ANDTHEREFORETHEEYEMOVEMENTSINRESPONSETO HEADPITCHORROLLARELIKELYTOBEALTEREDDURINGANDAFTERSPACEʅIGHT4HERESULTSOFTHE CENTRIFUGEEXPERIMENTHAVENOTCONʄRMEDTHISHYPOTHESIS THOUGHTHETORSIONALALONG THELINEOFSIGHT EYEMOVEMENTELICITEDBYTHELINEARACCELERATIONKNOWNASOCULAR COUNTER ROTATION WAS UNCHANGED IN ʅIGHT AND POSTʅIGHT RELATIVE TO PREʅIGHT -ORE INVESTIGATIONS ARE THEREFORE NECESSARY TO FULLY UNDERSTAND THE ADAPTATION OF THE COMPENSATORYEYEMOVEMENTSDURINGSPACEʅIGHT .EWTESTSOFTHEOTOLITHFUNCTIONARECURRENTLYINTRODUCEDTOEVALUATETHERE ADAPTATION OFEYEMOVEMENTSINRESPONSETOBODYTILTAFTERSPACEʅIGHT2ECENTLY WEINVESTIGATED THEEYEMOVEMENTSANDTHEPERCEPTIONOFCREWMEMBERSEXPOSEDTOBODYROTATIONABOUT ANAXISTILTEDFROM%ARTHȀSVERTICAL&IGURE LEFT 4HISOFF VERTICALAXISROTATION /6!2 CAUSES WHENROTATIONISINDARKNESSATACONSTANTLOWVELOCITY THEPERCEPTION OFBEINGSUCCESSIVELYTILTEDINALLDIRECTIONS#ONSEQUENTLY BOTHACOUNTER ROTATIONOF THEEYESANDAPERCEPTIONOFMOVINGALONGTHEEDGEOFANINVERTEDCONE APPEAR!T HIGHERROTATIONRATESTHEILLUSIONISTHATOFBEINGUPRIGHT BUTMOVINGALONGTHEEDGESOF ACYLINDERHENCEMORETRANSLATIONALMOTION ANDEYEMOVEMENTSAREPREDOMINANTLY HORIZONTAL !STRONAUTS RETURNING FROM SPACE MISSIONS GENERALLY EXPERIENCE A LARGER

Figure 3.18. Left. A Subject Rotating at Constant Velocity About an Axis Tilted Relative to the Vertical (Off-Vertical Axis Rotation) Has the Illusion of Describing Either a Conical or a Cylindrical Motion When Rotation Is at Low or High Velocity, Respectively. Right. In the z-Axis Aligned Gravitoinertial Force (ZAG) Paradigm, the Subject Is Sinusoidally Translated While Simultaneous Tilted Such as the Gravito-Inertial Force (GIF) Remains Aligned with the Longitudinal Body Axis. Both OVAR and ZAG Allow the Investigation of the Ambiguity Between tilt and Translation Motion Perception During Stimulation of the Otoliths on Earth [Clément and Reschke, 2008]. (Credit Philippe Tauzin).

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Figure 3.19. Left: Because the Observation Windows of the Shuttle and ISS Face Earth, Astronauts Often Have the Sensation of Looking “Down” to Earth. Right: Astronauts During EVA Occasionally Feel Uncomfortable When Working Upside-Down or When Their Feet Point to the Earth “Below”. (Credit NASA).

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Figure 3.20. Examples of Shapes Used for a Mental Rotation Test. When the Shape on the Extreme Left Is Presented with, Let’s Say, the Shape on the Extreme Right (a 180° Rotation), the Time Taken to Decide that Both Shapes Are the Same Is About 5 s. When the Shape on the Extreme Left Is Presented with the Shape in the Middle (a 90° Rotation), the Response Time Is Now Only 2.5 s. Therefore the Speed of Mental Rotation in This Test Is About 33°/s.

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VERTICALAXISOFSYMMETRYISEASIERTOIDENTIFYTHANAHORIZONTALORANOBLIQUEAXISOF SYMMETRY!CHANGEINTHEPOSITIONOFTHEHEADRELATIVETOTHETRUNKON%ARTHINʅU ENCES SYMMETRY DETECTION /NE EXPERIMENT PERFORMED IN SPACE ON ʄVE ASTRONAUTS INDICATED THAT BOTH VERTICAL AND HORIZONTAL AXES OF SYMMETRY WERE EQUALLY EASY TO IDENTIFY;,¦ONE = )NTERESTINGLYENOUGH MENTALTASKSTHATDEMANDLOGICALREASONING DECISION MAKING ASWELLASMEMORYRETRIEVALFUNCTIONS SEEMUNIMPAIREDDURINGSPACEʅIGHT4HISRESULT ISINCONʅICTWITHWHATISFREQUENTLYREPORTEDBYCREWMEMBERS4HATIS ITISDIFʄCULT TOEVALUATEELAPSEDTIMEPERIODSWHILEINSPACE  -ENTALREPRESENTATION !N ACCURATE REPRESENTATION OF THE VISUAL ENVIRONMENT IS CRUCIAL FOR THE SUCCESSFUL INTERACTIONWITHOBJECTSINANENVIRONMENT)TISCLEARTHATHUMANSHAVEMENTALREPRE SENTATIONSOFTHEIRSPATIALENVIRONMENTANDTHATTHESEREPRESENTATIONSAREUSEFUL IFNOT ESSENTIAL IN A WIDE VARIETY OF COGNITIVE TASKS SUCH AS IDENTIʄCATION OF OBJECTS AND LANDMARKS GUIDING ACTIONS AND NAVIGATION AND IN DIRECTING SPATIAL AWARENESS AND ATTENTION )NPHYSICS ACOORDINATESYSTEMTHATCANBEUSEDTODEʄNEPOSITION ORIENTATION AND MOTIONISCALLEDAREFERENCEFRAME)THASBEENARGUEDTHATTHE%ARTHȀSGRAVITATIONAL ʄELDISONEOFTHEMOSTFUNDAMENTALCONSTRAINTSFORTHECHOICEOFREFERENCEFRAMESFOR THE DEVELOPMENT AND THE USE OF COGNITIVE REPRESENTATIONS OF SPACE &OR EXAMPLE A SUBJECTLOOKINGATADIAMOND SHAPEDʄGUREINRETINALCOORDINATES PERCEIVESASQUARE SHAPEDʄGUREWHENHESHEANDTHEʄGUREAREBOTHTILTEDRELATIVETOGRAVITY4HISRESULT INDICATESTHATTHEPERCEPTIONOFTHEFORMOFANOBJECTGENERALLYDEPENDSMOREONTHE ORIENTATIONOFTHEOBJECTINWORLDSPATIAL COORDINATESTHANONITSORIENTATIONINRETINAL COORDINATES)NOTHERWORDS GRAVITYISCRITICALFORTHEEXTRACTIONOFANOBJECTȀSREFER ENCEFRAME /NEPROBLEMWITHGROUND BASEDSTUDIESONPERCEPTIONISTHATTILTINGTHEOBSERVER RELATIVETOGRAVITYON%ARTHCREATESACONʅICTBETWEENPERCEIVEDGRAVITATIONALEXTRIN SIC VERTICALANDRETINAL ORBODY DEʄNEDINTRINSIC VERTICAL BUTDOESNOTSUPPRESSTHE GRAVITATIONALINFORMATION/NTHEOTHERHAND THELOSSOFTHEGRAVITATIONALREFERENCEIN SPACEʅIGHTPROVIDESAUNIQUEOPPORTUNITYTODIFFERENTIATETHECONTRIBUTIONOFINTRINSIC ANDEXTRINSICFACTORSTOTHESPATIALORIENTATIONSYSTEM -EASURINGTHECHANGESINTHEMENTALREPRESENTATIONOFANOBJECTTHROUGHOUTASPACE MISSIONISASIMPLEWAYTOASSESSHOWTHEGRAVITATIONALREFERENCEFRAMEISTAKENINTO ACCOUNTFORSPATIALORIENTATION2ESULTSOFSPACESTUDIESBYOURGROUPSUGGESTTHATTHE ABSENCEOFTHEGRAVITATIONALREFERENCESYSTEM WHICHDETERMINESON%ARTHTHEVERTICAL DIRECTION INʅUENCESTHEMENTALREPRESENTATIONOFTHEVERTICALDIMENSIONOFOBJECTSAND VOLUMES&OREXAMPLE )ONCEASKEDA&RENCHASTRONAUTTOWRITEHISNAMEWITHHISEYES CLOSEDVERTICALLYANDTHENHORIZONTALLYONANOTEBOOKATTACHEDBY6ELCROTOHISKNEE 4HEPHYSICALLENGTHDIMENSIONOFTHESEWORDSONTHEPAGEWASCOMPAREDBETWEEN IN ʅIGHT AND PREʅIGHT TESTS 2ESULTS SHOWED THAT THE LENGTH OF THE WRITTEN WORDS DECREASEDIN ʅIGHTFORBOTHVERTICALANDHORIZONTALDIRECTIONS BUTTHEVERTICALDIREC TIONWASTHEMOSTAFFECTED;#L¦MENTETAL =)NANOTHERASTRONAUT THEREDUCTION INTHEVERTICALLENGTHOFWORDSWASOBSERVEDDURINGSEVERALDAYSAFTERRETURNINGFROM A DAYSPACEMISSION&IGURE )TISINTERESTINGTONOTETHATINBOTHEXPERIMENTS



&UNDAMENTALSOF3PACE-EDICINE

Figure 3.21. Left: Vertical Writing Test with the Eyes Closed in an Astronaut Before (Pre) and After (R + 1 to R + 7 Days) a Spaceflight. Right: Vertical Wri-ting Test in a Vestibular Patient. (Adapted from Fukuda [1983]).

THESIZEOFTHELETTERSDIDNOTCHANGEIN ʅIGHTORPOSTʅIGHT BUTTHEVERTICALDISTANCE BETWEENTHEMWASDECREASED4HISOBSERVATIONINDICATESTHATTHECHANGESWERENOT DUETOANALTERATIONINPROPRIOCEPTIONORMOTORCONTROL)NTERESTINGLY THESETESTSARE VARIANTSOFTESTSTRADITIONALLYUSEDINORIENTALMEDICINETHE&UKUDA7RITINGTEST THE 3QUARE$RAWINGTEST TODIAGNOSEPATIENTSWITHIMPAIRMENTINMOTORFUNCTIONWHEN THESIZEOFALLCHARACTERSISIRREGULAR FROMTHOSEWITHVESTIBULARDISORDERSTHEWRITING ORDRAWINGISDEVIATEDTOONESIDE !NDTHEASTRONAUTSȀRESPONSESARECLOSETOTHOSEOF PATIENTSWITHOTOLITHICDISORDERSON%ARTH4HESERESULTSSUGGESTTHATADAPTIVECHANGES INTHEMENTALREPRESENTATIONOFAVERTICALLAYOUTOFLETTERSTAKEPLACEWHENTHEGRAVITA TIONALFRAMEOFREFERENCEISREMOVEDEITHERBYMICROGRAVITYORBYCENTRALDISORDERS ;#L¦MENTAND2ESCHKE = $URING ANOTHER TEST TWO CREWMEMBERS WERE REQUESTED TO DRAW THE WELL KNOWN .ECKERȀSCUBE4HISʄGUREISTHESIMPLESTREPRESENTATIONOFATHREE DIMENSIONALOBJECT INATWO AXISCOORDINATESYSTEM#OMPARISONBETWEENTHELENGTHOFTHELINESBETWEEN THECUBESDRAWNONTHEGROUNDANDTHECUBESDRAWNINSPACEREVEALEDADECREASE INLENGTHINTHEVERTICALDIMENSIONIE THEHEIGHT OFTHECUBESDRAWNINWEIGHTLESS NESS&IGURE 3IMILARRESULTSHAVEBEENFOUNDINANOTHERSTUDYINVOLVINGTWO ASTRONAUTS4HETRAJECTORYOFHAND DRAWNELLIPSESINTHEFRONTALPLANEINTHEAIRWITH THEIREYESCLOSEDREVEALEDAǻDECREASEINTHEVERTICALLENGTHOFTHEELLIPSES WHEREASTHEHORIZONTALLENGTHOFTHEELLIPSESWASBASICALLYUNCHANGED4HISRESULTSUP PORTSOURHYPOTHESISTHATTHEMENTALREPRESENTATIONOFTHEVERTICALDIMENSIONOFOBJECTS ORVOLUMESISALTEREDDURINGEXPOSURETOWEIGHTLESSNESS  $EPTHPERCEPTION $EPTHPERCEPTIONISBASEDONACCOMMODATION BINOCULARDISPARITY MOTIONPARALLAX AS WELLASAERIALANDGEOMETRICALPERSPECTIVES&IGURE LEFT )NTHEABSENCEOFATMO SPHEREANDWITHDIFFERENTLIGHTINGCONDITIONSAFFECTINGCOLORANDCONTRAST ASINSPACE ʅIGHT AERIALPERSPECTIVEISPRESUMABLYTHEMOSTRELIABLEOFCUESFORDEPTHPERCEPTION 3PACE EXPERIMENTS HAVE BEGUN TO INVESTIGATE THE ROLE OF DEPTH CUES IN ABSENCE OF A GRAVITATIONALFRAMEOFREFERENCE(OWARDETAL;=HADSHOWNTHATTHEPERCEPTIONOF CONCAVITYORCONVEXITYOFASHAPEDEPENDSONAȃLIGHTCOMESFROMABOVEȄASSUMPTION

4HE.EURO 3ENSORY3YSTEMIN3PACE



Figure 3.22. Top: Mean ± SD of Each Point of Cubes Drawn by an Astronaut Preflight and In-Flight. Bottom: Averaged Mean Preflight and In-Flight Cubes. Horizontal and Oblique Lines Were Unchanged, but the Vertical Lines Were Shorter in Microgravity. (Adapted from Lathan et al. [2000]).

Figure 3.23. Monocular Cues for Depth Include Aerial Perspective, Which Entails the Loss of Contrast, Color, and Shading with Increasing Distance Due to Scattering of Light in the Atmosphere (left) and Geometrical Perspective, in Which Objects Appear Smaller When They Are Farther Away (right). Aerial and Geometrical Perspectives Are Both Affected by the Spaceflight Environment, Either Directly or Indirectly.

WHEREȃABOVEȄDEPENDSONTHEHEADORIENTATIONRELATIVETOTHEOBJECTANDGRAVITY$URING THE.EUROLABMISSION CREWMEMBERSWEREPRESENTEDWITHCONVEXORCONCAVESHADED ʄGURES!FTERSEVERALDAYSINSPACE THEYCOULDNOTUSESORELIABLYTHATLIGHTINFORMATION FORDEPTH BECAUSETHEYHADBEENEXPOSEDTOSITUATIONSWHERETHELIGHTSOURCECOULD COMEFROMANYDIRECTIONWHILETHEYWEREFREE ʅOATINGINTHECABIN;/MAN = /UR)33EXPERIMENTCALLED$ 30!#%SEE&IGURE ISUSINGCLASSICGEOMETRI CAL ILLUSIONS OF SIZE WHICH ON %ARTH GENERATE INACCURATE JUDGMENTS BECAUSE THEY PROVIDEMISLEADINGDEPTHCUES4HOSEILLUSIONSBASEDONPERSPECTIVEDEPTHCUESARE



&UNDAMENTALSOF3PACE-EDICINE

PARTICULARLYRELEVANTTOTHESPACEENVIRONMENT)NDEED GEOMETRICALPERSPECTIVEUSES CONVERGINGLINESANDVANISHINGPOINTSTODETERMINEHOWMUCHANOBJECTȀSAPPARENT SIZECHANGESWITHDISTANCE&IGURE RIGHT )TISBASEDONTHEPRINCIPLETHATTHERE ISATHEORETICALHORIZONLINEREPRESENTINGTHEPOINTOFVIEWOFTHEOBSERVER ANDTHATTHE ANGLEOFCONVERGINGLINESTOWARDAVANISHINGPOINT GENERALLYINTHESTRAIGHT AHEAD DIRECTION PROVIDESDEPTHINFORMATION)NTHEABSENCEOFAGRAVITATIONALREFERENCE SUCH AS IN MICROGRAVITY IT IS MORE DIFʄCULT TO DEʄNE A HORIZONTAL LINE !LSO PREVIOUS STUDIESHAVESHOWNSIGNIʄCANTDEVIATIONSINTHEVERTICALPOSITIONOFTHEEYEINMICRO GRAVITYDUETOTHESTIMULATIONOFTHEOTOLITHORGANSBYCHANGESINTHEAMPLITUDEOFTHE GRAVITO INERTIAL FORCES WHICH COULD ALTER THE DIRECTION OF THE ȃSTRAIGHT AHEADȄ #ONSEQUENTLY BECAUSETHERULESOFGEOMETRICALPERSPECTIVEARELESSACCURATELYDEʄNED INMICROGRAVITY THESUBJECTSSHOULDRELYLESSONTHEPERSPECTIVECUESFORDEPTHPERCEP TION4HEPRELIMINARYDATAFROMTHISEXPERIMENTTENDTOSUPPORTTHISHYPOTHESIS 4HERESULTSOFTHESESTUDIESMAYHAVEIMPORTANTCONSEQUENCESFORHUMANPERFOR MANCEDURINGSPACEʅIGHT&OREXAMPLE IFANASTRONAUTCANNOTACCURATELYVISUALIZETHE VOLUMEOFTHESTATION ITSSURROUNDINGS ORAPLANETARYSURFACE NAVIGATIONMAYCAUSE DELAYSANDFRUSTRATION4HEREMAYALSOBECONSEQUENCESFORSPACEHABITATDESIGNIF SQUAREDVOLUMESDONOTLOOKSQUARETOPEOPLEINSPACE6IRTUALREALITYTRAININGMIGHT BEAWAYTOTRAINTHEASTRONAUTSTOCOMPENSATEFORSUCHALTEREDSPATIALREPRESENTATION 2ECENT RESEARCH STUDIES HAVE USED ELECTROENCEPHALOGRAM %%' RECORDINGS TO MONITOR AND MEASURE WORKING MEMORY AND OTHER INDICATORS OF COGNITIVE ABILITY ! RECENT EXPERIMENT CONDUCTED OVER THE COURSE OF THREE SPACEʅIGHTS QUANTIʄED THE %%'OSCILLATIONSAT(Z WHICHARETHEMOSTPROMINENTRHYTHMSOBSERVEDINSUB JECTSWHOAREAWAKEWITHTHEIREYESCLOSED4HISACTIVITYINCREASEDINʄVECOSMONAUTS IN ʅIGHTCOMPAREDTOPREʅIGHT4HEAUTHORSOFTHISSTUDYATTRIBUTETHISINCREASETOA REDUCTIONINGRAVICEPTIVEINPUTSTOCORTICALNETWORKSPARTICIPATINGINTHEMENTALREPRE SENTATIONOFSPACE;#H¦RONETAL =&URTHERINVESTIGATIONSCARRIEDOUTINSPACE WILL PERHAPS REVEAL THAT OTHER HIGHER CORTICAL FUNCTIONS ARE IMPAIRED IN WEIGHTLESS CONDITIONS4HECOMBINATIONOFVIRTUALREALITYWITH%%'RECORDINGSFORTHEMEASURE MENTOFEVOKED RELATEDPOTENTIALSANDBRAINMAPPING SHOULDSOONPROVIDEINSIGHTFUL RESULTSONTHEADAPTIVEMECHANISMSOFCEREBRALFUNCTIONSINABSENCEOFGRAVITY (OWWILLTHECOGNITIVEPROCESSESOFSPATIALORIENTATIONDIFFERFROMTHETERRESTRIAL NORMAFTERALONGABSENCEOFAGRAVITATIONALREFERENCE7ESPECULATETHATTHEWAYOF PROCESSINGTHREEDIMENSIONSWILLBEMOREDEVELOPED#REATIVITYWILLCERTAINLYBEMORE THREE DIMENSIONALANDDEʄNITELYTHINKINGWILLBEOUTOFTHEGRAVITATIONALBOX,IKETHE WAYCULTUREANDLANGUAGEINʅUENCESOURABILITYTOTHINKCREATIVELY BEINGFREEFROM GRAVITYWILLELICITTHOUGHTSNEVERBEFOREPOSSIBLEFORTHEHUMANMIND ANDTHUSGIVE OPPORTUNITIESFORNEWARTANDSCIENTIʄCDISCOVERIES;0ETTIT =

 7HATDOWEKNOW  3PACEMOTIONSICKNESSEXPERIENCE 4HESEVERITYOF3-3ISCATEGORIZEDDEPENDINGONITSIMPACTUPONCREWPERFORMANCE 4ABLE &OREXAMPLE ȃ-ILDȄ3-3HASNOOPERATIONALIMPACT BECAUSETHECREW MEMBERCANSTILLPERFORMALLTHEREQUIREDACTIVITIESȃ-ODERATEȄORȃ3EVEREȄ3-3ARE

4HE.EURO 3ENSORY3YSTEMIN3PACE Table 3.1.



NASA Categorization of Space Motion Sickness According to the Severity of Symptoms. None

No signs or symptoms reported

Mild

One to several transient symptoms No operational impact All symptoms resolved in 36–48 h.

Moderate

Several symptoms of a persistent nature Minimal operational impact All symptoms resolved in 72 h.

Severe

Several symptoms of a persistent nature Significant performance decrement Symptoms may persist beyond 72 h

OPERATIONALCONCERNSSINCETHEWORKLOADMUSTBEREDISTRIBUTEDAMONGTHEREMAINING UNAFFECTEDCREW )NTHESPACESHUTTLEMISSIONSBETWEENAND ABOUTOFTHECREW MEMBERSMAKINGTHEIRʄRSTʅIGHTREPORTEDSYMPTOMSOF3-3!BOUTREPORTED MILDSYMPTOMS MODERATESYMPTOMS ANDSEVERESYMPTOMS-OSTRECOV EREDBYTHEENDOFTHETHIRDDAYINSPACE)NAFEWCASESINTHE2USSIANAND53MIS SIONS HOWEVER CREWMEMBERSWEREILLFORǻDAYS 4HESEVERITYOF3-3AMONGTHOSEMAKINGASECONDʅIGHTREMAINEDUNCHANGEDIN OFCREWMEMBERS WHEREASASLIGHTIMPROVEMENTWASOBSERVEDIN BUTEVEN MORESYMPTOMSWERENOTEDIN4HISINDICATESTHATSYMPTOMSARENOTSIGNIʄCANTLY REDUCEDONAFOLLOWINGʅIGHT )N ADDITION TO FEELINGS OF VERTIGO AND NAUSEA 3-3 CAN CAUSE SOPITE SYNDROME WHICHINCLUDESLACKOFMOTIVATIONTOWORKORINTERACTWITHOTHERS DROWSINESS FATIGUE ANDTHEINABILITYTOCONCENTRATE3OPITESYNDROMEISOFTENABYPRODUCTOFDIZZINESS EXPERIENCEDBYASTRONAUTSDURINGSPACETRAVEL 3-3ISSELF LIMITED#OMPLETERECOVERYFROMMAJORSYMPTOMSIE ADAPTATIONTO THE SPACEʅIGHT ENVIRONMENT OCCURS WITHIN ǻ DAYS !FTER COMPLETE ADAPTATION OCCURS CREWMEMBERSAPPEARTOBEIMMUNETOTHEDEVELOPMENTOFFURTHERSYMPTOMS 4HISDEVELOPMENTOFIMMUNITYTOFURTHER3-3SYMPTOMSWASDEMONSTRATEDBYROTAT INGCHAIRTESTS DESIGNEDTOPROVOKEAN3-3RESPONSE THATWERECONDUCTEDIN ʅIGHT DURING3KYLABMISSIONS 

4HEORIESFORSPACEMOTIONSICKNESS

4WOMAJORTHEORIESADVANCEDTOACCOUNTFOR3-3ARETHEʅUIDSHIFTTHEORYANDTHE SENSORYCONʅICT ALSOKNOWNASTHENEURALMISMATCH SENSORYMISMATCH ORSENSORY REARRANGEMENT THEORY ;#RAMPTON = !LTHOUGH BOTH THEORETICAL POSITIONS HAVE SOMEMERITANDNEITHERISIDEAL THEʅUIDSHIFTTHEORYDOESNOTEXPLAINTHEDEVELOPMENT )NTHEJARGONOFTHEʅIGHTSURGEONS ȃ-ILDȄSYMPTOMSARESOMETIMESREFERREDTOȃONEBAGȄ ȃ-ODERATEȄTO ȃTWOBAGSȄ ANDȃ3EVEREȄTOȃTHREEBAGSȄ





&UNDAMENTALSOF3PACE-EDICINE

OFMOTIONSICKNESSDURINGSPACEʅIGHTWEDONȀTGETSICKWHENLYINGINABED 7HILE THE ʅUID SHIFT THEORY OF 3-3 COULD BE ASSOCIATED WITH SENSORY CONʅICT THERE ARE MECHANISMS WHEREBY THE HEADWARD ʅUID SHIFT ACCOMPANYING MICROGRAVITY COULD BYPASSTHECLASSICVESTIBULARINPUTSTOINDUCEVOMITING "RIEʅY THESENSORYCONʅICTTHEORYOFMOTIONSICKNESSASSUMESTHATHUMANORIENTA TIONIN$SPACE UNDERNORMALGRAVITATIONALCONDITIONS ISBASEDONATLEASTFOURSEN SORY INPUTS TO THE CENTRAL NERVOUS SYSTEM 4HE OTOLITH ORGANS PROVIDE INFORMATION ABOUTLINEARACCELERATIONSANDTILTRELATIVETOTHEGRAVITYVECTORANGULARACCELERATION INFORMATIONISPROVIDEDBYTHESEMICIRCULARCANALSTHEVISUALSYSTEMPROVIDESINFOR MATIONCONCERNINGBODYORIENTATIONWITHRESPECTTOTHEVISUALSCENEORSURROUNDAND TOUCH PRESSURE AND SOMATO SENSORY OR KINESTHETIC SYSTEMS SUPPLY INFORMATION ABOUTLIMBANDBODYPOSITION)NNORMALENVIRONMENTS INFORMATIONFROMTHESESYS TEMS IS COMPATIBLE AND COMPLEMENTARY AND MATCHES THAT EXPECTED ON THE BASIS OF PREVIOUSEXPERIENCE7HENTHEENVIRONMENTISALTEREDINSUCHAWAYTHATINFORMATION FROM THE SENSORY SYSTEMS IS NOT COMPATIBLE AND DOES NOT MATCH PREVIOUSLY STORED NEURALPATTERNS MOTIONSICKNESSMAYRESULT 4HESENSORYCONʅICTTHEORYPOSTULATESTHATMOTIONSICKNESSOCCURSWHENPATTERNS OFSENSORYINPUTSTOTHEBRAINAREMARKEDLYRE ARRANGED ATVARIANCEWITHEACHOTHER ORDIFFERSUBSTANTIALLYFROMEXPECTATIONSOFTHESTIMULUSRELATIONSHIPSINAGIVENENVI RONMENT)NMICROGRAVITY SENSORYCONʅICTCANOCCURINSEVERALWAYS&IRST THERECAN BE CONʅICTING INFORMATION IE REGARDING TILT TRANSMITTED BY THE OTOLITHS AND THE SEMICIRCULARCANALS3ENSORYCONʅICTMAYALSOEXISTBETWEENTHEVISUALANDVESTIBULAR SYSTEMSDURINGMOTIONINSPACETHEEYESTRANSMITINFORMATIONTOTHEBRAININDICATING BODYMOVEMENT BUTNOCORROBORATINGIMPULSESARERECEIVEDFROMTHEOTOLITHSSUCH ASDURINGCARSICKNESS !THIRDTYPEOFCONʅICTMAYEXISTINSPACEBECAUSEOFDIFFER ENCESINPERCEPTUALHABITSANDEXPECTATIONS/N%ARTH WEDEVELOPANEURALSTOREOF INFORMATION REGARDING THE APPEARANCE OF THE ENVIRONMENT AND CERTAIN EXPECTATIONS ABOUTFUNCTIONALRELATIONSHIPSEG THECONCEPTSOFȃUPȄANDȃDOWNȄ )NSPACE THESE PERCEPTUAL EXPECTATIONS ARE AT VARIANCE ESPECIALLY DURING THE INVERSION ILLUSIONS DESCRIBEDABOVE )TISIMPORTANTTONOTETHATNOSINGLECOURSEOFSENSORYCONʅICTAPPEARSTOENTIRELY ACCOUNTFORTHESYMPTOMSOFSPACESICKNESS2ATHER ITISTHECOMBINATIONOFTHESE CONʅICTSTHATSOMEHOWPRODUCESSICKNESS ALTHOUGHTHEEXACTPHYSIOLOGICALMECHA NISMSREMAINUNKNOWN4HUS SENSORYCONʅICTEXPLAINSEVERYTHINGINGENERAL BUT LITTLEINTHESPECIʄC3HORTCOMINGSOFTHESENSORYCONʅICTTHEORYINCLUDEA ITSLACK OFPREDICTIVEPOWERB THEINABILITYTOEXPLAINTHOSESITUATIONSWHERETHEREISCONʅICT BUTNOSICKNESSC THEINABILITYTOEXPLAINSPECIʄCMECHANISMSBYWHICHCONʅICT ACTUALLYGIVESRISETOVOMITINGANDD THEFAILURETOADDRESSTHEOBSERVATIONTHAT WITHOUTCONʅICT THERECANBENOADAPTATION4HEHYPOTHESESOUTLINEDBELOWMAYBE HELPFULINOVERCOMINGSOMEOFTHEWEAKNESSESASSOCIATEDWITHTHECONSTRUCTOFTHIS THEORY

 )THASBEENPROPOSEDTHATMOTIONSICKNESSRESULTSFROMTHEACTIVATIONOFAVESTIBULARMECHANISMWHOSE PHYSIOLOGICALFUNCTIONISTHEREMOVALOFPOISONSFROMTHESTOMACH.AUSEAANDVOMITINGWOULDALSOTEND TOKEEPADISORIENTEDORDIZZYINDIVIDUALFROMMOVINGABOUTTHEENVIRONMENTINSEARCHOFFOODWHENHE WOULDBEATRISKDOINGSO;-ONEY =

4HE.EURO 3ENSORY3YSTEMIN3PACE



3OME INVESTIGATORS HAVE PROPOSED A MECHANISM COMPLEMENTARY TO THE SENSORY CONʅICTTHEORYTOEXPLAININDIVIDUALDIFFERENCESIN3-3SUSCEPTIBILITY4HEYSUGGEST THATSOMEINDIVIDUALSPOSSESSSLIGHTFUNCTIONALIMBALANCES FOREXAMPLEWEIGHTDIFFER ENCES BETWEENTHERIGHTANDLEFTOTOLITHRECEPTORSTHATARECOMPENSATEDBYTHE#.3IN G!WEIGHTIMBALANCEBETWEENTHELEFTANDRIGHTOTOCONIAISREASONABLESINCETHERE ISACONTINUALTURNOVEROFOTOCONIA ANDITISUNLIKELYTHATTHETWOOTOLITHSWOULDEVER WEIGHEXACTLYTHESAME4HISCOMPENSATIONISINAPPROPRIATEING HOWEVER BECAUSE THEWEIGHTDIFFERENTIALISNULLIʄEDANDTHECOMPENSATORYRESPONSEEITHERCENTRALOR PERIPHERAL ISNOLONGERCORRECTFORTHENEWINERTIALENVIRONMENT4HERESULTWOULDBE ATEMPORARYASYMMETRYPRODUCINGROTARYVERTIGO INAPPROPRIATEEYEMOVEMENTS AND POSTURALCHANGESUNTILTHEIMBALANCEISCOMPENSATEDORADJUSTEDTOTHENEWSITUATION ! SIMILAR IMBALANCE WOULD BE PRODUCED UPON RETURN TO  G RESULTING IN POSTʅIGHT VESTIBULAR DISTURBANCES )NDIVIDUALS WITH A GREATER DEGREE OF ASYMMETRY IN OTOLITH MORPHOLOGYWOULDTHUSBEMORESUSCEPTIBLETO3-3 !SENSORYCOMPENSATIONHYPOTHESISHASALSOBEENPROPOSED3ENSORYCOMPENSA TIONOCCURSWHENTHEINPUTFROMONESENSORYSYSTEMISATTENUATEDANDSIGNALSFROM OTHERSAREAUGMENTED)NTHEABSENCEOFANAPPROPRIATEGRAVICEPTORSIGNALORPERHAPS THEPRESENCEOFATYPICALSIGNALS INMICROGRAVITY INFORMATIONFROMOTHERSPATIALORIEN TATIONRECEPTORSSUCHASTHEEYES THESEMICIRCULARCANALS ANDTHENECKPOSITIONRECEP TORSWOULDBEUSEDTOMAINTAINSPATIALORIENTATIONANDMOVEMENTCONTROL4HEINCREASE INRELIANCEONVISUALCUESFORSPATIALORIENTATIONCOULDBEEXPLAINEDBYTHISMECHA NISM#LOSELYRELATEDTOTHISSENSORYCOMPENSATIONHYPOTHESISISTHE/442HYPOTHESIS ALREADYDISCUSSEDSEE&IGURE  

#OUNTERMEASURES

4HEDISRUPTIVENATUREOF3-3 OCCURRINGASITDOESDURINGTHEEARLY CRITICALSTAGESOF AMISSION HASLEDTOAVARIETYOFAPPROACHESFORTHEPREVENTIONORCONTROLOFTHISMEDI CALPROBLEM 0REDICTIONOFSUSCEPTIBILITYHASBEENAMAJOROBJECTIVEOFTHE3-3RESEARCH6ARIOUS APPROACHESRANGINGFROMTHEUSEOFQUESTIONNAIRES HISTORY EXPERIENCEORPERSONALITY TRAITS VESTIBULARFUNCTIONTESTS PHYSIOLOGICALCORRELATES ANDTESTSINSPECIʄCNAUSEO GENIC ENVIRONMENTS HAVE BEEN DIRECTED TOWARD THE QUESTION OF 3-3 SUSCEPTIBILITY (OWEVER STRIKINGDIFFERENCESWEREFOUNDINTHEPATTERNOFSYMPTOMSGENERATEDDURING ʅIGHT COMPARED TO THE PATTERN GENERATED DURING THE GROUND BASED TESTS &URTHER THE SPECIʄCNATUREANDTIMECOURSEOFIN ʅIGHTSYMPTOMATOLOGYWEREHIGHLYVARIABLE4HE PREʅIGHTQUESTIONNAIRERESULTSDIDNOTCORRELATEWITHTHEREPORTEDINCIDENCEOF3-3 $IFFERENCESINTHERESULTSBETWEENSUSCEPTIBLEANDNON SUSCEPTIBLECREWMEMBERSFOR EACH OF THE PREʅIGHT TESTS WERE NOT SIGNIʄCANT NOR WAS THE CORRELATION BETWEEN SUSCEPTIBILITYTOMOTIONSICKNESSINTHEGROUND BASEDTESTSANDSUSCEPTIBILITYTO3-3 )NDIVIDUALVARIATIONSINPREʅIGHTEXPERIENCE MEDICATIONS IN ʅIGHTTASKSIE MOBILITY ANDPERSONALSTRATEGIESFORSYMPTOMMANAGEMENTHAVEFURTHERCOMPOUNDEDTHEPROB LEM #ONSEQUENTLY THE USE OF A SINGLE GROUND BASED PARAMETER OR TEST PROCEDURE IS INADEQUATEFORPREDICTING3-3SUSCEPTIBILITY$ESPITETHEINABILITYTOIDENTIFYGROUND BASEDPREDICTORSOF3-3SUSCEPTIBILITY ONEREASONABLYACCURATEPREDICTORWASIDENTI ʄED ANDTHATISSPACEʅIGHTITSELF/FCREWMEMBERSWHOHADʅOWNTWOORMORE SPACEMISSIONS THERESPONSEPATTERNOFONLYTHREECHANGEDFROMONEʅIGHTTOTHENEXT



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Figure 3.24. Preflight Adaptation Training. Before the Flight, Crewmembers Are Passively Tilted in Roll or in Pitch While Exposed to a Lateral Translation of the Visual Scene (Such as on the left panel) or to a Fore/Backward Translation, Respectively, in Order to Induce a Reinterpretation of Their Otolith Signals by the Visual System. (Credit NASA).

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Figure 3.25. Scanning Electron Micrographs of Otoliths from Quail Embryos That Were Raised from Fertilization in Microgravity (left), in an Onboard 1-g Centrifuge (center), and in a 2-g Centrifuge on Earth. (Adapted from Evans et al. [2009]).

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Figure 4.1. Astronauts Onboard the ISS Are Using an Ultrasound Machine to Perform Exam of the Heart and Other Internal Organs. Ultrasound Probes Send HighFrequency (Megahertz) Sound Waves into the Body. Because Sound Waves Travel Through Each Organ, or Tissue, at a Different Speed, the Probe Is Able To “See” What the Reflected Sound Waves Have Found. (Credit NASA).

/RTHOSTATIC INTOLERANCE AFFECTS ABOUT TWO THIRDS OF THE ASTRONAUTS RETURNING FROM SPACEʅIGHT EVEN AFTER MISSIONS OF RELATIVELY SHORT DURATION ;"UCKEY ET AL A= 4HISISANEVENGREATERPROBLEMFORSPACESHUTTLEPILOTS WHOMUSTPERFORMCOMPLEX RE ENTRYMANEUVERSINANUPRIGHT SEATEDPOSITION/PERATIONALCONCERNSHAVEINCREASED SINCEASTRONAUTSBEGANUSINGTHEHEAVY BULKYPARTIAL PRESSURIZEDLAUNCHANDRE ENTRY SUIT REQUIREDFORALLPOST #HALLENGERʅIGHTS(OWEVER ESSENTIALLYNOTESTINGOFCAR DIO VASCULARFUNCTIONHASBEENPERFORMEDONSPACESHUTTLEPILOTSDURINGRE ENTRY4HIS MAYPOSEAPROBLEMFORȃSPACETOURISTSȄDURINGSUBORBITALʅIGHT4HEYWILLBEEXPOSED TO RE ENTRY FORCES EVEN HIGHER THAT THOSE EXPERIENCED IN THE SPACE SHUTTLE OR 3OYUZ CAPSULES BY WELL CARDIO VASCULAR ʄT PROFESSIONAL ASTRONAUTS  !NOTHER THREAT IS WHETHERADEBILITATEDCREWCANRESPONDTOANEMERGENCYUPONLANDING )TISESTIMATEDTHATAPPROXIMATELYOFCREWSONLONG DURATIONMISSIONSEXPERI ENCESOMEDEGREEOFORTHOSTATICINTOLERANCEAFTERRETURNTO%ARTH4HEEXTENTOFORTHO STATIC INTOLERANCE POSTʅIGHT IS VARIABLE AND DEPENDS ON THE DURATION OF THE ʅIGHT INDIVIDUAL DIFFERENCES IN CARDIO VASCULAR FUNCTION AMONG THE ASTRONAUTS AND THE ELAPSEDTIMEAFTERLANDINGANDMETHODOFPOSTʅIGHTTESTING2ECOVERYTOTHEPREʅIGHT LEVELOFORTHOSTATICTOLERANCEOCCURSWITHINADAYORSOFOLLOWINGʅIGHTSOFLESSTHANA  MONTH DURATION BUT LONGER RECOVERY IS ASSOCIATED WITH LONGER DURATION ʅIGHTS ;7ATENPAUGHAND(ARGENS = 2ECOVERY OF EXERCISE CAPACITY IS ALSO RELATIVELY RAPID BUT TAKES ABOUT  WEEK FOLLOWINGASHORTDURATIONSPACEʅIGHT&OLLOWINGLONGDURATIONSPACEʅIGHTSONBOARD

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THE 2USSIAN SPACE STATIONS 3ALYUT AND -IR MANY RETURNING COSMONAUTS WERE INCAPACITATEDANDWEREUNABLETOEGRESSTHECAPSULEWITHOUTASSISTANCEFROMGROUND PERSONNEL&IGURE !SASTANDARDROUTINE CREWSRETURNINGFROMA MONTHSPACE ʅIGHTUNDERGOMANYWEEKSOFREHABILITATION WITHGRADUATEDEXERCISES GUIDEDMOVE MENTSINAWARMSWIMMINGPOOL ANDMASSAGE%VENWITHTHISREHABILITATIONPROGRAM AFTERAFEWMONTHSSOMEREPORTEDTHATTHEYCOULDNȀTJOGWITHOUTBECOMINGSHORTOF BREATH;0AYNEETAL = 4HE)33CREWMEMBERSAREENCOURAGEDTOEXERCISEDURINGTHEEARLYPHASESOFAMIS SIONASACOUNTERMEASURETOMITIGATETHEEFFECTSOFMICROGRAVITY JUSTLIKETHE3KYLAB AND-IRCREWMEMBERSWHOWENTBEFORETHEM4HE3KYLABAND-IRCREWMEMBERSDID NOTMANIFESTANYDIFFERENCESBETWEENTHEIRHEARTRATERESPONSESDURINGʅIGHTASCOM PAREDTOPREʅIGHTVALUES4HEEXERCISEPROGRAMBEGINSWITHHOFSCHEDULEDEXERCISE TIMEONʅIGHTDAYANDINCREASESTOHOFEXERCISEAFTERSPACESHUTTLEOR3OYUZ UNDOCKING!DETAILEDANALYSISOF)33CREWEXERCISECAPABILITYWASNOTPOSSIBLEPRIOR TO %XPEDITION  BECAUSE OF PAYLOAD CONSTRAINTS PAYLOAD PRIORITIES AND BUDGETARY ISSUES2ECENTDATAHASREVEALEDADECREASEINFUNCTIONALCAPACITYBOTHINORBITAND UPONLANDINGINNINE53ASTRONAUTSANDFOUR2USSIANCOSMONAUTS UNLIKEWHATWAS OBSERVEDINTHE3KYLABASTRONAUTS;-OOREETAL = 4HE EFFECTS OF EXPOSURE TO MICROGRAVITY ON THE CARDIO VASCULAR SYSTEM BEYOND  MONTHS ARE LARGELY UNKNOWN 4HIS IS OF GREAT CONCERN BECAUSE SUCH EFFECTS MAY INVOLVE NOT ONLY AMPLIʄCATION OF REVERSIBLE CHANGES ALREADY KNOWN BUT ALSO THE

Figure 4.2. After a Long-Duration Stay in Orbit, Cosmonauts Are So Severely Debilitated That They Cannot Egress the Soyuz Capsule Without Assistance from Ground Personnel. (Credit Roscosmos).



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EMERGENCEOFUNRECOGNIZEDANDIRREVERSIBLEALTERATIONSINCARDIO PULMONARYFUNCTION &OREXAMPLE SOMEOBSERVERSHAVESPECULATEDTHATTHEREISALOSSOFCARDIACMASSDUR ING PROLONGED MICROGRAVITY EXPOSURE 7ILL LENGTHY MISSIONS RENDER SPACE TRAVELERS UNʄTFORRETURNTOA GENVIRONMENT *ETPILOTSOFTENʅYUPSIDEDOWNATȪGWITHNOPROBLEM&IGURE 7HYTHEN WOULDʅYINGINGPOSEAPROBLEM(OWCANTHESESPACETRAVELERSPERFORMNOMINALLY ONORBITANDTHENBESODEBILITATEDWHENTHEYLAND3YMPTOMSOFORTHOSTATICHYPOTEN SIONARESEENON%ARTHWITHPATIENTSWHOHAVECERTAINTYPESOFCARDIO VASCULARDISEASE $ID THE SPACE AGENCIES SOMEHOW PICK INDIVIDUALS WHO WERE SUSCEPTIBLE TO THESE PROBLEMS)NFACT THEASTRONAUTSSELECTEDBY.!3!AREINITIALLYSCREENEDFORSIGNIʄ CANT CARDIO VASCULAR DISEASES SEE #HAPTER  3ECTION   4HEY ARE IN EXCELLENT PHYSICALSHAPEANDMANYHAVEINCREASEDHEARTMUSCLEMASSCOMPAREDTOTHETERRESTRIAL ȃNORMALȄPOPULATION 3O WHATISTHERISK4HERISKOFCARDIO VASCULARMEDICALEVENTSHAPPENINGDURING ORAFTERAMISSIONCANBEDIVIDEDINTOTWOCATEGORIESA THOSEMEDICALEVENTSWHICH OCCURASACONSEQUENCEOFPRE EXISTINGCARDIO VASCULARDISEASEWHICHMUSTNOTBE DETECTED DURING THE SELECTION MEDICAL EXAMINATION AND ARE AGGRAVATED BY SPACE ʅIGHT AND B THOSE MEDICAL EVENTS THAT OCCUR AS A CONSEQUENCE OF THE EXPECTED CARDIO VASCULARPHYSIOLOGICALCHANGESINDUCEDBYSPACEʅIGHT!RECENTSTUDYBASED ONEXPERIENCEWITHAIRCRAFTPILOTSHASDETERMINEDTHATTHERISKOFAȃMISSIONLOSSȄ DUETOSERIOUSCARDIO VASCULAREVENT LIKEAHEARTATTACKORASUSTAINEDRHYTHMDISTUR BANCE DURINGA DAYSPACEʅIGHTWITHASIX PERSONCREWISPERʅIGHT4HE WORST CASE CARDIO VASCULAR RISK OF AN INCAPACITATING EVENT FOR )33 CREWS OVER A  YEARPERIODISPERPERSONPERYEARIFALLOTHERSPACE RELATEDFACTORSAREIGNORED ;"ARRATTAND0OOL =

Figure 4.3. During Acrobatic Flying, Pilots Often Fly Upside-Down and Are Exposed to −1 g with No Problems. (Source Unknown).

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 #ARDIO VASCULARSYSTEMPHYSIOLOGY  "ASICS 4HE MAJOR FUNCTIONS OF THE CARDIO VASCULAR SYSTEM INCLUDE A DELIVERY OF / AND NUTRIENTSTOALLAREASOFTHEBODYANDB REMOVALOF#/ANDCELLMETABOLICWASTESTO SPECIʄCORGANS SUCHASTHELUNGSORKIDNEYS/THERFUNCTIONSOFTHECARDIO VASCULAR SYSTEMASITCIRCULATESBLOODINCLUDETHETRANSPORTOFHORMONES TRANSPORTOFIMMUNE SYSTEMCOMPONENTSSUCHASWHITEBLOODCELLSORANTIBODIES ANDHEATREGULATION 4HESEFUNCTIONSWEREORIGINALLYLOCALIZEDWITHINTHEUNIQUECELLOFEARLY UNICEL LULAR ORGANISMS (OWEVER AS ORGANISMS INCREASED IN SIZE AND IN NUMBER OF CELLS ISOLATEDINDIVIDUALCELLSALSONEEDEDTOINGESTNUTRIENTSANDEXCRETEWASTE&IGURE  4HEDEVELOPMENTOFAVASCULARTREE ABLETOREACHALLINDIVIDUALCELLS WASTHEREFORE REQUIRED3UCHASYSTEMINCLUDESBOTHTHEHEARTANDTHEBLOODVESSELSTHATPASSTOAND FROMTHEHEARTTOTHETISSUESOFTHEBODY4HESEVESSELSINCLUDETHELARGEARTERIESTHAT RECEIVEBLOODFROMTHEHEART BRANCHINGINTOSMALLERARTERIOLESTHATBRANCHFURTHERINTO CAPILLARIES&ROMTHECAPILLARIES BLOODʅOWSINTOSMALLCOLLECTINGVENULES THENINTO LARGERANDLARGERVEINSFORRETURNTOTHEHEART 4HEOVERALLORGANIZATIONOFTHECARDIO VASCULARSYSTEMCONSISTSOFADRIVINGPUMP THEHEART ANDTHETWOKEYCIRCULATORYSYSTEMSTHATITPOWERSTHEPULMONARYCIRCULA TIONTHELUNGS ANDTHESYSTEMICCIRCULATIONTHERESTOFTHEBODY )NTHESYSTEMIC CIRCULATION THEARTERIESTRANSPORTOXYGENATEDBLOODUNDERRELATIVELYHIGHPRESSURESTO THEBODYATAPPROXIMATELYǻMM(GPRESSURE ANDTHEVEINSRETURNDEOXYGENATED BLOODTOTHEHEARTATLOWERPRESSURESOFǻMM(G4HECAPACITYOFTHEVENOUSSYS TEMISLARGEANDATLEASTOFTHEBLOODVOLUMEINHUMANSISFOUNDINTHEVEINS4HE MEANARTERIALPRESSUREREPRESENTSTHEAVERAGEPRESSURETHATPUSHESBLOODTHROUGHTHE CAPILLARIESANDOTHERVESSELSOFTHESYSTEMICCIRCULATION4HISPRESSURELEVELPROVIDES INSIGHTINTOTHEAVERAGEBLOODʅOWTOTHETISSUES/N%ARTH THEREISALARGEPRESSURE GRADIENTFROMTHEHEADTOTHEFEET WITHTHEMEANARTERIALBLOODPRESSUREBEINGABOUT

Figure 4.4. Why Do We Have a Cardio-Vascular System? When Single-Celled Organisms, Living in an Aqueous Environment, Evolved to Larger and Larger Multi-cellular Organisms, the Metabolic Needs of the Cells in the Interior of the Enlarging Structure Could No Longer Be Satisfied by Simple Diffusion with the Surrounding Liquid Environment. A Vascular Tree Was Eventually Required to Bring in the Necessary Materials to the Individual Cells and to Carry Out the Undesired By-Products of Their Metabolism. Thus, the Primary Function of the Cardio-Vascular System Is to Deliver a Flow of Blood to Local Tissues So That Individual Cells in Those Tissues Can Be Maintained in Optimal Condition [Churchill, 1999]. (Credit Philippe Tauzin).



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MM(GATTHEHEADLEVEL MM(GATTHEHEARTLEVEL ANDMM(GATTHEFEET LEVEL4HISISBECAUSETHEVASCULARSYSTEMISESSENTIALLYASETOFVERTICALȃCOLUMNSȄOF BLOOD ANDPRESSUREINTHESECOLUMNSINCREASESWITHDEPTH JUSTASPRESSUREINCREASES WITHDEPTHINTHEOCEAN&IGURE  )NTHEPULMONARYCIRCULATION THEDEOXYGENATEDBLOODISCARRIEDBYPERFUSIONFROM THERIGHTVENTRICLEOFTHEHEARTTOTHELUNGSVIATHEPULMONARYARTERY4HISISALOW PRESSURE SYSTEM TYPICALLY ǻ MM(G WITH LOW RESISTANCE TO BLOOD ʅOW )N AN INDIVIDUALSTANDINGUPRIGHT THISPRESSUREMAYBEINSUFʄCIENTTOOVERCOMEHYDROSTATIC GRADIENTS ANDSOVERYLITTLEʅOWREACHESTHEUPPERREGIONSOFTHELUNGS BUTARELA TIVELYLARGEPORTIONOFPULMONARYBLOODʅOWPERFUSESTHELOWERPORTIONSOFTHELUNGS !IRINTHEALVEOLIʅOWSSOMEWHATPREFERENTIALLYINTOTHEMIDDLEANDUPPERREGIONSOF THELUNGS4HESEREGIONALDIFFERENCESCREATEAMISMATCHOFAIRVENTILATIONANDBLOOD PERFUSIONANDARETHEBASISFORTHESYSTEMOFCLASSIʄCATIONOFLUNGZONES;7EST = !STHEBLOODʅOWSTHROUGHTHECAPILLARIESINTHELUNGS WASTEGASESIE #/ ARE RELEASEDANDOXYGENISABSORBEDBYSIMPLEDIFFUSION"LOODTHENPASSESTOTHELEFT ATRIUMOFTHEHEARTVIATHEPULMONARYVEINS&ROMTHERE THEOXYGENATEDBLOODPASSES TOTHELEFTVENTRICLETOBEPUMPEDOUTOFTHEHEARTAGAIN 4HE CONTRACTION OF THE HEART ʄRST ATRIA AND THEN VENTRICLES IS TERMED SYSTOLE "ETWEENBEATS THEHEARTPAUSESBRIEʅYFORTHEATRIATOREʄLLWITHBLOODFORTHENEXT CONTRACTION4HISPERIODISTERMEDDIASTOLE"LOODPRESSUREINTHEARTERIESʅUCTUATES DURINGTHESEPHASESOFTHEFULLCARDIACCYCLE!RTERIALPRESSURERISESSHARPLYDURING VENTRICULARSYSTOLEANDDROPSDURINGVENTRICULARDIASTOLE&LOWTHROUGHABLOODVESSEL ISDETERMINEDBYBOTHTHEFORCETHATPUSHESTHEBLOODTHROUGHTHATVESSELANDTHERESIS TANCEOFTHEVESSEL )TISALSOIMPORTANTTONOTETHATTHEʅOWOFBLOODINTHEBODYISDIRECTLYINʅUENCED BYGRAVITY7HENAPERSONISSTANDING GRAVITYCAUSESBLOODTOPOOLINTHERELATIVELY COMPLIANTLEGVEINS4HEFORCEOFGRAVITYALSOMAKESITMOREDIFʄCULTFORTHEBLOODTO ʅOW UPWARD TO RETURN TO THE HEART AND LUNGS FOR MORE OXYGEN "ECAUSE THE VEINS

Figure 4.5. On Earth, When We Are Standing, There Is a Hydrostatic Pressure Gradient from Head-to-Foot. The Veins of Our Lower Legs Sustain a Pressure of Approximately 200 mmHg. An Immediate Effect of Transition to Micro-Gravity Is loss of Hydrostatic Gradient in the Venous Vascular System, Similar to Being Supine on Earth.

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Figure 4.6. The Contraction of Skeletal Muscles in the Legs Helps to Pump Blood Toward the Heart, but Is Prevented from Pushing Blood Away from the Heart by Closure of the Venous Valves. (Adapted from Lujan and White [1994]. Credit Philippe Tauzin).

C OMPRISE A LOW PRESSURE SYSTEM WITH VERY DISTENSIBLE WALLS IN MANY CASES BLOOD WOULDTENDTOPOOLINTHEMUNLESSSOMETHINGAIDSTHEʅOW-OSTVEINSHAVEVALVESIN THEM WHICHPREVENTANYȃBACK ʅOWȄ)NADDITION APERIODICPUSHINGOFBLOODFOR WARDEVERYTIMESKELETALMUSCLESINTHELEGSCONTRACTASSISTSVENOUSRETURN&IGURE  4HISMECHANISMEFFECTIVELYCOUNTERACTSTHEFORCEOFGRAVITY 

#ONTROLMECHANISMS

 #ONTROLOFBLOODPRESSURE 4HECARDIO VASCULARSYSTEMISWELLKNOWNASTHEMAJORʅUIDTRANSPORTATIONSYSTEMOF THEHUMANBODY)TSREGULATEDTRANSPORTTOANDFROMTHECAPILLARIESISCENTRALTOLIFE FROMTHECELLULARTOWHOLE PERSONLEVEL9ETTHEPLASMAOFTHECARDIO VASCULARSYSTEM CONTAINSONLYABOUT,OFTHETOTALBODYWATERCONTENTOF,ABOUT FORA KG ȃAVERAGEȄ MALE !NOTHER  , OF WATER ARE LOCATED IN THE EXTRACELLULAR INTERSTITIAL SPACES THESPACESINBETWEENTHECELLS ANDINTHELYMPHATICVESSELSTHATDRAINTHOSE SPACES4HEREMAINING,OFWATERISTHEINTRACELLULARʅUIDINSIDECELLSOFTHEBODY %XCEPTINTHECASEOFBLEEDING CHANGESINBLOODVOLUMEUSUALLYOCCURBECAUSEOF CHANGESINTHEWATERCONTENTOFTHEBLOODPLASMA)NCREASINGTOTALBLOODVOLUMEULTI MATELYINCREASESTHEȃʄLLINGPRESSUREȄOFTHEVASCULARSYSTEMANDTHEAMOUNTOFBLOOD TOBEEJECTEDBYTHEHEARTWITHEACHSTROKE 4HEVOLUMEOFBLOODDISCHARGEDFROMTHELEFTVENTRICLEOFTHEHEARTWITHEACHCON TRACTIONISCALLEDTHESTROKEVOLUMEABOUTM,ATREST 7ITHAHEARTRATEOFBEATS MIN BLOODʅOWINTHEENTIREHUMANCIRCULATIONISABOUT M,MINATREST BUTMAY BEǻTIMESGREATERDURINGEXERCISE4HEAMOUNTOFBLOODPUMPEDBYTHEHEARTIN MINISCALLEDTHECARDIACOUTPUT Cardiac Output  Stroke Volume r Heart Rate

mL of blood / min mL of blood / beat beats / min

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"OTHHEARTRATEANDSTROKEVOLUMECANCHANGE THUSVARYINGCARDIACOUTPUTANDTHE SUPPLY OF BLOOD TO THE ENTIRE CIRCULATION #ONTROLLING BLOOD VESSEL RADIUS WHICH IS DONEBYTHESYMPATHETICNERVOUSSYSTEM ISALSOAVERYPOWERFULWAYFORTHEBODYTO VARYTHERESISTANCEOFTHEVESSELTOTHEBLOODʅOW DIVERTʅOWFROMONEAREATOANOTHER ANDVARYBLOODPRESSUREOVERALL"LOODPRESSUREWILLALSOVARYASAFUNCTIONOFTHE VISCOSITY OF THE BLOOD SUCH AS THE QUANTITY OF BLOOD CELLS WITHIN THE PLASMA 4ABLE  "OTHHEARTRATEANDBLOODPRESSUREARECONTROLLEDBYTHEAUTONOMIC UNCONSCIOUS NERVOUS SYSTEM WHICH CONSISTS OF TWO PARTS THE PARA SYMPATHETIC AND THE SYMPA THETIC NERVOUS SYSTEMS 4HESE TWO SYSTEMS HAVE OPPOSING ROLES AND ARE ACTIVATED ACCORDINGTOTHEDIFFERENTNEEDSOFTHEINDIVIDUAL4HEPARASYMPATHETICNERVOUSSYS TEMISACTIVATEDDURINGRESTANDASSISTSINENERGYRESTORATIONBYMEANSOFTHEDIGESTION ANDABSORPTIONOFFOOD4HISSYSTEMALSOACTSTODECREASEHEARTRATE4HESYMPATHETIC NERVOUSSYSTEM ONTHEOTHERHAND PREPARESTHEBODYFORANEMERGENCYANDCOUNTER ACTS THE PARASYMPATHETIC NERVOUS SYSTEM TO MAINTAIN THE REQUIRED ENERGY SUPPLY $URING ANY EMOTIONAL OR PHYSICAL STRESS ADRENALINE IS RELEASED BY THE SYMPATHETIC NERVOUSSYSTEM WHICHACTSTOINCREASEHEARTRATEANDBLOODPRESSURE !CCORDINGLY ABALANCEBETWEENTHEPARASYMPATHETICANDSYMPATHETICNERVOUSSYS TEMSACTIVITYCONTROLSHEARTRATE/NABEAT TO BEATBASIS HOWEVER ITHASBEENOBSERVED THATHEARTRATEISNOTCONSTANTANDTHEREAREPERIODICALʅUCTUATIONSINDICATIVEOFTHE RELATIVE CONTRIBUTIONS OF EACH OF THESE TWO COMPONENTS OF THE AUTONOMIC NERVOUS SYSTEM4HEREHAVEBEENVARIOUSMETHODSEMPLOYEDINANATTEMPTTOQUANTIFYTHERELA TIVECONTRIBUTIONSOFEACHOFTHESESYSTEMS/NEOFTHEMOSTCOMMONLYUSEDMETHODS IS THE FREQUENCY DOMAIN ANALYSIS OF HEART RATE VARIABILITY 4HIS METHOD USES HIGHLY SOPHISTICATEDTECHNIQUESTODETERMINEDIFFERENTFREQUENCIESOFHEARTRATE ANDFROMTHIS ANALYSISONECANIDENTIFYWHICHOFTHETWOSYSTEMSISPREDOMINANTLYACTIVEDURING BOTHRESTANDEXERCISE

Table 4.1.

Some Factors That Influence Arterial Blood Pressure and the Associated Mechanisms.

Factors

Why Blood Pressure Increases

Increase in blood volume

Increased total “filling pressure” in the semi-flexible cardio-vascular system; increased venous return to the heart, leading to higher stroke volume

Increase in heart hate

Increased cardiac output which, without a countering change in peripheral resistance, increases pressure

Increase in stroke volume

Same as increased heart rate

Increase in peripheral resistance

Normally varied by changing vessel diameter, particularly in the arterioles, increased constrictive resistance increase pressure in the vessels leading up to it

Increase in blood viscosity

Increased resistance, as thicker blood does not flow as easily

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 "ARORECEPTORREʅEXES "ARORECEPTORS ORȃPRESSURERECEPTORS ȄARESPECIALIZEDNERVEENDINGSLOCATEDINBOTH THE ARTERIAL AND VENOUS SYSTEMS WHICH ARE STIMULATED WHEN THE BLOOD VESSELS ARE STRETCHEDBYINCREASEDPRESSURE4HEBARORECEPTORSINTHEARTERIALSYSTEMARELOCATEDIN THENECKASTHECAROTIDARTERYASCENDSTOTHEBRAIN ANDINTHEAORTICARCH IMMEDIATELY ASBLOODLEAVESTHEHEARTINTHEAORTA&IGURE 7HENBLOODPRESSUREINCREASES THE CORRECTIVERESPONSEVIATHESTIMULATIONOFTHEBARORECEPTORSANDSYMPATHETICNERVOUS SYSTEMINCLUDESADECREASEINHEARTRATEANDSTROKEVOLUMEANDVASODILATATIONOFTHE ARTERIOLESTODECREASEVASCULARPERIPHERALRESISTANCE)NADDITION SECONDARYEFFECTSACT ONTHEKIDNEYTOALLOWINCREASEDURINEPRODUCTION4HEREVERSEEFFECTSTAKEPLACEIF BLOODPRESSUREISDECREASED "ARORECEPTORSINTHEVENOUSSYSTEMARERATHERDIFFUSELYLOCATEDANDLESSUNDERSTOOD CLASSICALLY)NGENERAL THESERECEPTORSARESCATTEREDINTHEMAJORVEINSENTERINGTHE HEART THEATRIA ANDTHEPULMONARYVESSELSALSOCALLEDTHEVENACAVA "ECAUSETHE LARGE VEINS ARE VERY COMPLIANT CHANGING GREATLY IN VOLUME WITH SMALL PRESSURE CHANGES THEVENOUSBARORECEPTORSAREACTUALLYMONITORINGRATHERSIGNIʄCANTCHANGES INVENOUSBLOODVOLUMEINTHEUPPERBODY!LTHOUGHLESSWELLCHARACTERIZEDTHANTHEIR ARTERIALCOUNTERPARTS ITISPOSSIBLETHATTHESEARETHEʄRSTBARORECEPTORSACTIVATEDBY ʅUIDSHIFTSTHATOCCURINSPACEʅIGHT )TISNOWBELIEVEDTHATSPACEʅIGHTDECONDITIONSTHEBARORECEPTORRESPONSE RESULT INGINLARGERCHANGESINTHEBARORECEPTORDISTENTIONNEEDEDTOINDUCETHESAMECHANGES

Figure 4.7. Arterial Baroreceptors Are Located in the Aortic Arch and the Carotid Sinuses of the Left and Right Internal Carotid Arteries. Whenever These Sensors Are Stretched or Relaxed, Nervous Signals Are Transmitted to the CNS, Which Communicates with the Heart and Peripheral Arterial Resistance Vessels. (Adapted from Norsk and Karemaker, [2008]).



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INHEARTRATEINGCOMPAREDTOG4HEREISALSOMOREANDMOREEVIDENCETHATTHE VESTIBULARSYSTEMPLAYSASIGNIʄCANTROLEINTHEREGULATIONOFBLOODPRESSURE$URING THE TRANSITION FROM VARIOUS POSTURES THE STIMULATION OF THE OTOLITH ORGANS BY THE CHANGESINHEADORIENTATIONRELATIVETOGRAVITYCOULDBEUSEDASASIGNALFORTRIGGERING FASTADJUSTMENTINBLOODPRESSURE;9ATES =4HISRESPONSEWOULD OFCOURSE BE ALTEREDINMICROGRAVITY /VERALL ALTHOUGH THE BARORECEPTORS AND VESTIBULAR RECEPTORS RESPOND RAPIDLY TO PRESSURE AND ACCELERATION CHANGES RESPECTIVELY THE RESPONSE IS NOT IMMEDIATE !NYONEWHOHASSTOODUPVERYQUICKLYFROMARECLININGORKNEELINGPOSITIONKNOWS THATAFEWSECONDSOFDIZZINESSMAYRESULT4HISDIZZINESSISTHEPERIODWHENTHEBRAIN ISRECEIVINGTOOLITTLEBLOODʅOWWHILETHEBODYȀSREʅEXESWORKTOCORRECTBLOODPRES SUREINTHEUPPERBODY*ETPILOTSPERFORMINGHIGH GTURNEXPERIENCETHESAMETHING 4HEREISAȃLAGȄPERIODBEFORECARDIO VASCULARRESPONSESBEGINTOACCOMMODATETOTHE G INDUCEDMOVEMENTOFBLOODDOWNWARDFROMTHEIRHEADSTOTHEIRFEET$URING AND EVENBEFORE THISCRITICALTIMEPILOTSMUSTBEESPECIALLYVIGILANTTOMAINTAINTHEIRBLOOD PRESSUREBYSPECIALSTRAININGMANEUVERSTHATINCREASEBLOODPRESSUREFURTHERAIDEDBY ARAPID REACTINGANTI GSUITTHATINʅATESONTHEIRLEGSANDABDOMENTOPUSHBLOODBACK TOWARDS THE UPPER BODY  3UCH LAG TIMES IN BODY REʅEXES ARE NOT SO IMPORTANT IN MICROGRAVITY BECAUSETHEHEADWARDʅUIDSHIFTTOWHICHTHEBARORECEPTORSARERESPOND INGISAMUCHSLOWERANDCHRONICCONDITION BEGINNINGASTHEASTRONAUTSRECLINEINTHEIR SEATSFORLAUNCHANDCONTINUINGON ORBIT  &LUIDVOLUMEREGULATION ,ONG TERMREGULATIONOFBLOODPRESSUREANDRELATEDBLOODVOLUMEAREPRIMARILYCON TROLLEDBYTHEKIDNEYS4HEMAINPARAMETERCONTROLLEDISBLOODPLASMAVOLUME THE LIQUIDPORTIONOFTHEBLOOD5LTIMATELY THECELLULARCOMPONENTSOFTHEBLOODAREALSO CONTROLLED BY PRODUCING OR DESTROYING RED AND WHITE BLOOD CELLS AND PLATELETS (OWEVER THISISASECONDARYANDLONGER TERMPHENOMENON 4HEKIDNEYSPLAYALARGEROLEINTHEREGULATIONOFʅUIDVOLUMEINTHEBODYANDAID INTHECONTROLOFREDBLOODCELLPRODUCTIONANDBLOODPRESSURE4HEKIDNEYSALSOHELP TO MAINTAIN THE NORMAL CONCENTRATIONS OF WATER AND ELECTROLYTES IN THE BODY ʅUIDS 4HISCONTROLISDEPENDENTUPONHORMONESREGULATINGTHESALTANDWATERBALANCE&OR EXAMPLE THEANTI DIURETICHORMONE!$( ISAPOLYPEPTIDEHORMONERELEASEDTHROUGH THEPOSTERIORPITUITARYGLANDOFTHEBRAINWHENITSENSESANINCREASEINPLASMAOSMOLAR ITY RELATIVE SALT CONCENTRATION 4HE !$( HORMONE ACTS DIRECTLY ON THE KIDNEYS TO CAUSETHEMTORETAINMOREWATER4HISWATERTHENDILUTESTHEBLOODPLASMAANDINCREASES PLASMAVOLUME!LTERNATELY AREDUCTIONIN!$(LEVELSWILLCAUSETHEELIMINATIONOF MOREWATERFROMTHEBODY

 %ARTHȀSGRAVITYMAYDETERMINETHELOCATIONANDSIZEOFINTERNALORGANSSUCHASTHEHEART&OREXAMPLE ,ILLYWHITEETAL;=NOTICEDTHATTHEHEARTOFTHETREESNAKE THATISCRAWLINGUPANDDOWNTREESAND THEREFOREMUSTCOPEWITHGRAVITY WASCLOSERTOTHEBRAINTHANTHELANDORSEASNAKES WHOSPENDMOSTOF THEIRLIFEINAHORIZONTALPOSITIONORARENEUTRALLYBUOYANT4HETREESNAKEWASTHEMOSTTOLERANTTOCENTRIFU GATION SUGGESTINGTHATITWOULDBEMOREGRAVITYTOLERANTTHANTHEOTHERSNAKESASITDIDNOTHAVETOCARRY BLOODOVERASGREATADISTANCEFROMTHEHEARTTOTHEBRAIN;-OREY (OLTON =

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#ERTAINKIDNEYCELLSAREALSOSENSITIVETOARTERIALPRESSUREINABARORECEPTORFASHION SYMPATHETICNERVOUSSYSTEMACTIVITY ORCIRCULATINGEPINEPHRINEFROMTHESYMPATHETIC NERVOUSSYSTEM)NRESPONSETOLOWBLOODPRESSUREORINCREASEDSYMPATHETICNERVOUS ACTIVITY THESECELLSINITIATEARATHERCOMPLEX MULTI STAGEPROCESSTHATSERVESTORETAIN ORELIMINATEWATERANDELECTROLYTES )NSUMMARY )CITETHEANALOGYPROPOSEDBY,EVINE;=ȃ)TISHELPFULTOTHINK ABOUTTHESYSTEMASMADEUPOFȃTHEPLUMBINGȄ COMPRISEDOFTHEȃPUMPȄTHEHEART AND ȃPIPESȄ THE BLOOD VESSELS AND THE ȃCONTROL SYSTEMȄ THE AUTONOMIC NERVOUS SYSTEM HORMONES REGULATING SALT AND WATER BALANCE AND LOCAL ENDOTHELIAL DERIVED MEDIATORSOFMICROVASCULARʅOW &ORACUTEDEMANDS SUCHASDURINGEXERCISEORRAPID CHANGESINPOSTURE HIGHERORDERCENTERSINTHEBRAININITIATEANINCREASEINTHEHEART RATE TERMEDȃCENTRALCOMMANDȄ3ENSORSLOCATEDINSKELETALMUSCLERESPONDTOCHANGES INBOTHMETABOLICANDMECHANICALSTATEANDSENDBACKSIGNALSTOTHEBRAINREʅECTIVEOF THEINTENSITYOFEFFORT4HEHEARTITSELFISASENSORYORGANANDDETECTSTHEADEQUACY OF HYDRATION AND CARDIAC ʄLLING THROUGH ȃMECHANORECEPTORSȄ 0RESSURE SENSORS OR ȃBARORECEPTORSȄINTHEWALLSOFTHELARGEBLOODVESSELSDETECTTHEPRESSUREWITHINTHE VASCULATURE4HESESIGNALSAREINTEGRATEDINSPECIALCENTERSINTHEBRAIN WHICHRESPOND BYREGULATINGBOTHTHESTRENGTHANDFREQUENCYOFTHEHEARTȀSCONTRACTIONANDTHERESIS TANCEOFTHEBLOODVESSELS PRIMARILYBYNEURALMECHANISMSȄ

 %FFECTSOFSPACEʅIGHT 2APIDTRANSITIONBETWEENUPRIGHT SITTING ANDLYINGDOWNPOSTURESREQUIRESTHATTHE HEART AND BLOOD VESSELS RESPOND VERY QUICKLY /N %ARTH THIS IS ACHIEVED BY VERY SOPHISTICATEDCONTROLCENTERS4HESECONTROLCENTERSARECHALLENGEDDURINGSPACEʅIGHT 7HENHYDROSTATICGRADIENTSAREREMOVED SUCHASCHANGINGFROMTHEUPRIGHTTOTHE SUPINEPOSITIONOREXPOSURETOMICROGRAVITY BLOODISSHIFTEDFROMTHELOWERPARTOFTHE BODYTOWARDSTHECHESTVIRTUALLYDOUBLINGTHEAMOUNTOFBLOODINSIDEOFTHEHEART4HE HEARTRESPONDSTOTHISVOLUMELOADBYINCREASINGTHEAMOUNTOFBLOODITPUMPS ANDBY INITIATINGBOTHAREDISTRIBUTIONANDELIMINATIONOFPLASMA 2ESEARCHSTUDIESHAVEFOCUSEDONUNDERSTANDINGTHEEFFECTSOFSPACEʅIGHTONTHE CARDIO VASCULARSYSTEMBYSTUDYINGCARDIACOUTPUT HEARTRATE BLOODVESSELBEHAVIOR BLOODPRESSURE ANDBLOODVOLUMEDURINGSPACEʅIGHTANDUPONRETURNTO%ARTH/NE AIMOFTHESESTUDIESISTODETERMINEPRECISELYWHENʅUIDSHIFTSOCCUR BECAUSETHEYARE BELIEVEDTOBETHEPRECURSOROFOTHERPHYSIOLOGICCHANGESTHATOCCURINMICROGRAVITY 

,AUNCHPOSITION

)TISIMPORTANTTOREALIZETHATTHEASTRONAUTSAREORIENTEDINALMOSTAHORIZONTALPOSITION WHILE WAITING FOR A LAUNCH IN THE SPACE SHUTTLE OR 3OYUZ &IGURE   4HE CREW IS PLACEDINTHISPOSITIONAPPROXIMATELYHPRIORTOTHEEXPECTEDLAUNCHTIME ANDTHEY CANSTAYTHEREFORASLONGASHBEFORE-ISSION#ONTROLCONSIDERSALAUNCHSCRUB4HIS SUPINEPOSITIONWITHAmHIPANDKNEEʅEXIONISCHOSENTODIRECTTHELAUNCHACCELERA TIONINTHEHORIZONTALDIRECTIONOFTHEBODY'X BACK TO CHEST FORWHICHTHETOLER ANCEISGREATER4ABLE SEE&IGURE 

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Figure 4.8. During Launch on Board Soyuz, Astronauts Are Reclined on Their Backs in Molded Couches, with Their Legs Higher Than Their Heads. This Prevents Blood from Pooling in the Legs During Ascent and Assists the Heart in Pumping Blood to the Rest of the Body. (Credit NASA).

Table 4.2. Tolerance to Vertical (Gz) and Horizontal (Gx) Acceleration [Elert, 2002].

Vertical Acceleration (g, Up Is Positive)

Event or Symptom

16

Limit of human tolerance, centrifugea

12–14

Ejection seat

11.4

Acrobatic airplane

4.5–6.3

Loss of consciousness

3.9–5.5

Complete loss of vision (black-out)

3.4–4.8

Partial loss of vision (gray-out)

4.5

Roller-coaster, maximum at bottom of first dip

−1

Congestion of blood in head

−2

Severe blood congestion, reddening of vision (red-out)

−5

Limit of sustained human tolerance

Horizontal Acceleration (g, Magnitude Only)

Event or Symptom

0.4

“Pedal to the metal” in a typical car

0.8

“Pedal to the metal” in a high performance sports car

2

Extreme Launch™ roller-coaster at start (Continued)

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE Table 4.2.



(Continued)

Horizontal Acceleration (g, Magnitude Only)

Event or Symptom

3

Space Shuttle, maximum at takeoffb Jet fighter landing on aircraft carrier

8

Limit of sustained human tolerance

21–35

Limit of human tolerance, centrifugea, 5-s duration

40–80

USAF chimpanzee, centrifugea, 60-s duration

60

Chest acceleration during car crash at 48 km/h with airbag

70–100

Car crash that killed Diana, Princess of Wales, 1997

83

Human subject, rocket powered impact sled, 0.04-s duration

247

USAF chimpanzee, rocket powered impact sled, 0.001 s

3,400

Impact acceleration limit for crash-survivable flight recorder

The passenger capsule of a human centrifuge pivots so that a test subject in a seat would experience a vertical acceleration while a test subject lying down would experience a horizontal acceleration. b During lift off, the space shuttle, which is pointing more or less upward, is accelerated in the direction of its vertical axis, but the passengers (who are lying on their backs) are accelerated in the direction of their horizontal axes. a

4HEEFFECTOFTHISSPECIʄCSUPINEPOSITIONISTHATSIGNIʄCANTBLOODVOLUMEISPLACED ABOVETHEHEART THEREBYINCREASINGPRE LOADTOTHEHEARTCENTRALVENOUSPRESSURE AND CARDIACOUTPUT$URINGTHEEARLYPORTIONOFTHISORIENTATION ASUBJECTȀSSTROKEVOLUME INCREASESFROMABOUTM,BEATTOABOUTM,BEAT4HISISENTIRELYEXPECTED BECAUSE THEREISARUSHOFʅUIDSTOTHEUPPERPARTOFTHEBODYANDTHEHEARTHASTHENMOREBLOOD TOFORCEOUTDURINGEACHBEAT4HEBODYCOMPENSATESINPARTFORTHISSITUATIONBYREDUC INGBLOODVOLUMETHROUGHURINATIONANDREDUCEDTHIRST3HUTTLEASTRONAUTSWEARUNDER GARMENTSWITHAʅUID ABSORBENTMATERIALTHATPERMITSTHEMTOURINATEINSIDETHELAUNCH SUITS IF NECESSARY (OWEVER SOME ASTRONAUTS SOMETIME PREFER TO RESTRICT THEIR ʅUID INTAKEFROMTOHBEFORELAUNCHANDȃʅYDRYȄTOPREVENTUSINGTHEDIAPER4HISMAY WORKINTHESHORTTERMHOWEVER ITPUTSTHEMINTOORBITINAʅUID DEPLETEDSTATE)NADDI TION SUCH REDUCTION IN BLOOD VOLUME ON THE LAUNCH PAD MAY IMPAIR THEIR ABILITY TO EXECUTEANEMERGENCYEGRESSANDCOULDPROVOKESYNCOPEUPONSTANDINGUPQUICKLY 3PACESHUTTLEEMERGENCYEGRESSPLANSDURINGLAUNCHORLANDINGCALLFORTHECREWTO ESCAPETHROUGHTHESIDEHATCHORʅIGHTDECKWINDOWS$URINGTHESEPHASES THECREW ISWEARINGA KGSPACESUIT WHICHINCLUDESALIFESUPPORTSYSTEMANDAPARACHUTE )TISPERTINENTTOASKWHETHER AFTERSEVERALHOURSINTHELAUNCHSUPINEPOSITION EVERY CREWMEMBERWOULDBEABLETOUSETHEESCAPESYSTEM ANDEGRESSRAPIDLYWITHOUTANY ASSISTANCE 

%ARLYON ORBIT

 &LUIDSHIFT /NCETHELAUNCHPHASEISCOMPLETE THEHEADWARDʅUIDSHIFTCONTINUESINMICROGRAVITY RELATIVETONORMAL%ARTHȀSCONDITIONS4HISSHIFTISTHOUGHTTOOCCURBECAUSETHEMECH ANISMS THAT NORMALLY ACT TO COUNTER THE POOLING OF BLOOD IN THE LOWER EXTREMITIES



&UNDAMENTALSOF3PACE-EDICINE

Figure 4.9. Fluid Shift During Space-Flight. (a). On Earth, Because of the Down-Ward Pull of Gravity, the Body Easily Supplies Blood to the Lower Limbs. (b). Early On-Orbit, Blood Volume Shifts Toward the Chest and Head, Resulting in More Blood Than Usual in the Upper Portion of the Body. (c). This Increase Triggers the Receptors, Which Then Cause the Body to Reduce the Volume of Fluid. The Body Functions with Less Fluid and the Heart Becomes Smaller. (d). When Astronauts Return to Earth, the Bulk of the Blood Goes Back Down to the Legs, and Because the Total Amount of Blood has Decreased, There Isn’t Enough to Fill up the Whole System of Blood Vessels. This Contributes to the Occurrence of Orthostatic Hypotension.

CONTINUE TO ACT EVEN IN THE PRESENCE OF GRAVITY 4HIS HEADWARD ʅUID SHIFT ACTUALLY CREATESAMOREEVENDISTRIBUTIONOFʅUIDSANDAMOREEVENDISTRIBUTIONOFBLOODPRES SURESTHANISSEENON%ARTH&IGUREB 4HISINITIALʅUIDSHIFTOCCURSRAPIDLYANDIS VIRTUALLYCOMPLETEWITHINTHEʄRSTǻHOFʅIGHT4HEEFFECTSOFTHISHEADWARDʅUID SHIFTTENDTOLASTFORTHEENTIREDURATIONOFTHEʅIGHT4HEMOSTOBVIOUSEFFECTISAVIS IBLEDISTENSIONOFVEINSINTHEHEADANDNECKREGION ASWELLASPUFʄNESSAROUNDTHE EYES4HEASTRONAUTSSENSETHISʅUIDSHIFTANDDESCRIBEITASAȃFULLNESSINTHEHEADȄOR ANASALSTUFʄNESSSIMILARTOCHRONICSINUSCONGESTION4HESENSESOFSMELLANDTASTE MAYBEALTERED ASHAPPENSON%ARTHWHENONEHASACOLD3OMEASTRONAUTSALSOREPORT INCREASEDPRESSURESINSIDETHEEYEFORAFEWDAYSANDPAININTHEEYESWHENTHEYEXE CUTELARGEOCULARSACCADES/CCASIONALHEADACHESHAVEBEENREPORTED ANDINTRACRANIAL PRESSUREISSTILLBEINGSTUDIEDTOSEEHOWANDIFITCHANGESINMICROGRAVITYASAPOSSIBLE CORRELATETOTHISANDOTHEREFFECTSSUCHASNAUSEA  )NCONTRASTTOTHEUPPERBODY THELEGSEXPERIENCEANETLOSSOFʅUIDSASGENERAL CAPILLARYPRESSURESDECREASETHERE4HISLEADSTOASO CALLEDȃCHICKENLEGSYNDROMEȄ ASLEGVOLUMEDECREASESWITHTIMEINMICROGRAVITY3TUDIESHAVESHOWNTHATLEGCIR CUMFERENCEMAYDECREASEǻ MOSTLYINTHEʅESHIERTHIGHS ASUPTO,OFʅUID

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



SHIFTHEADWARD&LUIDSHIFTSCLEARLYACCOUNTFORTHEʄRSTPHASEOFTHISDECREASE;-OORE AND4HORNTON = 4HIRSTISGENERALLYDECREASEDEARLYIN ʅIGHT ANDASTRONAUTʅUIDINTAKEISREDUCED )NPART THISMAYBEARESULTOFTHEHEADWARDʅUIDSHIFTSANDSUPPRESSIONOFNORMAL THIRST REʅEXES (OWEVER THERE ARE NO INDICATIONS THAT URINE OUTPUT IS INCREASED IN SPACE;.ORSK =4HEREDUCEDʅUIDINTAKEMAYALSOBEDUETOTHEEFFECTSOFSPACE MOTIONSICKNESSINMANYCREWMEMBERSFORTHEʄRSTǻDAYSOFSPACEʅIGHT5SEOF ANTI MOTIONSICKNESSDRUGS MISSIONACTIVITIES ANDMANYOTHERFACTORSCANALSOAFFECT HYDRATIONANDURINEVOLUMEINSPACE  "LOODPRESSURE /NEMEASUREMENTOFSPECIALINTERESTINCARDIO VASCULARPHYSIOLOGYISTHECENTRALVENOUS PRESSURE#60 4HE#60ISTHEPRESSUREINTHEVENACAVA WHICHARETHELARGEVEINS RETURNINGBLOODFROMTHESYSTEMICCIRCULATIONTOTHERIGHTATRIUMOFTHEHEART4HISPRES SUREREPRESENTSTHEBLOODȃAVAILABLEȄTOBEPICKEDUPBYTHERIGHTATRIUMBEFOREEACH CONTRACTIONCYCLE4HISMEASUREMENTSHOULDTHEREFOREESTABLISHTHEAMOUNTOFʅUIDS THATREDISTRIBUTEORSHIFTTOTHEUPPERPARTOFTHEBODYANDHOWRAPIDLYTHATʅUIDSSHIFT OCCURS4HEʄRSTDIRECTMEASUREMENTSOF#60INHUMANSOCCURREDDURINGA3PACELAB MISSIONIN WHENONEASTRONAUTWASLAUNCHEDWITHACATHETEREXTENDINGINTOTHE INFERIORVENACAVANEARTHEHEART&IGURE 2ESULTSWERECONʄRMEDINLATER3PACELAB MISSIONS$ATAHAVEINDICATEDANINCREASEIN#60BEFORELAUNCH WHENTHEASTRONAUTS AREINTHEKNEES UPSEATEDPOSITION ANDAFURTHERINCREASEDURINGLAUNCHANDASCENT /NE MINUTE AFTER REACHING MICROGRAVITY THOUGH #60 DECREASED BELOW PRE LAUNCH

Figure 4.10. One Spacelab Experiment Used a Catheter Inserted Preflight into an Arm Vein of an Astronaut and Later Moved Nearer to the Heart. This Catheter Had a Sensor Attached, Which Measured the Blood Pressure Closest to the Heart. The Experiment Showed That the Astronauts Experience a Much More Rapid Fall in Central Venous Blood Pressure Than What Was Predicted by the Model. (Adapted from Lujan and White [1994]).

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LEVELS AND STAYED LOWER THAN NORMAL ;&OLDAGER ET AL  "UCKEY ET AL B= 4HEINCREASEIN#60BEFOREANDDURINGTHEACTUALLAUNCHPHASEWEREEXPECTED BECAUSE OF THE RUSH OF ʅUIDS TO THE RIGHT ATRIUM DUE TO THE SUPINE POSITION AND THE G FORCES COMPRESSINGTHECHESTAREA RESPECTIVELY(OWEVER THEDECREASEIN#60ONCETHEASTRO NAUTSARRIVEDINSPACE EVENTHOUGHTHEBODYʅUIDSCONTINUEDTOSHIFTUPWARD ANDTHE FACTTHAT#60FELLTOALEVELBELOWNORMALWITHINMINUPONENTERINGTHESPACEENVI RONMENT WASTOTALLYUNEXPECTED )NMICROGRAVITY THEDECREASED#60MAYINDICATETHATVENOUSCOMPLIANCEOFTHO RACICBLOODVESSELSINCREASESRAPIDLYTOHOLDTHEINCREASEDʅUIDSATALOWERPRESSURE 4HISINCREASEDSPACEFORʅUIDBUILD UPAROUNDTHEHEARTCOULDBEENHANCED FOREXAM PLE BY REMOVAL OF THE WEIGHT OF THE LUNGS ON VEINS THAT SURROUND THE HEART /THER SHORT TERMCHANGESINCLUDEANINCREASEINHEARTRATEANDANINCREASEINHEARTSIZEDUE TOEXCESSIVEʅUIDVOLUME;&RISCHE 9ELLEETAL = 4O ASCERTAIN WHETHER A CHANGE IN BLOOD PRESSURE IS INDUCED BY A CHANGE IN THE AMOUNTOFBLOODPUMPEDBYTHEHEARTORBYDILATIONOFTHEPERIPHERALARTERIES CARDIAC OUTPUTMUSTBEMEASURED"ECAUSETHEAMOUNTOFBLOODTHATPASSESTHROUGHTHELUNGS ISEQUALTOTHEAMOUNTOFBLOODTHATʅOWSOUTOFTHEHEARTCARDIACOUTPUT MEASURING GASEXCHANGESCANBEUSEDTODETERMINECARDIACOUTPUT4HEREFORE SCIENTISTSMONITOR AGASMIXTURETHATTHESUBJECTINHALESANDEXHALES!SITPASSESTHROUGHTHELUNGS THE BLOODABSORBSATRACERTHATISINTHEGASMIXTURE4HEABSORPTIONSRATEISPROPORTIONAL TOTHEAMOUNTOFBLOODʅOWINGTHROUGHTHELUNGS4HISPROPORTIONALITYRELATIONSHIP ALLOWSTHENFORADIRECTCALCULATIONOFCARDIACOUTPUT!NINCREASEOFINTHERATE OFTRACERUPTAKEOCCURSDURINGTHEʄRSTDAYSTHATANASTRONAUTISINSPACE ASCOMPARED TOTHEUPRIGHTSTANDINGPOSITIONON%ARTH4OGETHERWITHTHEDECREASEINBLOODPRES SURE ASDESCRIBEDPREVIOUSLY THISINCREASEINCARDIACOUTPUTSUGGESTSTHATTHEARTERIAL RESISTANCEVESSELSAREMOREDILATEDINGTHANING4HEVALUESINSPACEARECOMPA RABLETOTHOSEOBTAINEDINASITTINGPOSITIONON%ARTH)NOTHERWORDS THECARDIO VASCULAR SYSTEMRELAXESAFTERJUSTWEEKINSPACE;.ORSKAND+AREMAKER = 

,ATERON ORBIT

 &LUIDSHIFT 4HEHEADWARDʅUIDSHIFTTRIGGERSTHEBARORECEPTORS WHICHINFORMTHECONTROLCENTERS WHICH IN TURN ELIMINATE THE EXCESS OF ʅUID IN THE UPPER BODY &IGURE C  /VER SEVERALDAYS THEBLOODVOLUMEDECREASESASARESULTOFDECREASEDTHIRSTANDINCREASED WATEROUTPUTBYTHEKIDNEYS4OTALLOSSOFʅUIDFROMTHEVASCULARANDTISSUESPACESOF THELOWEREXTREMITIESHASBEENFOUNDTOBEǻ,ABOUTAǻVOLUMECHANGE COMPAREDTOPREʅIGHT 7ITHINǻDAYSINSPACE TOTALBODYWATERSTABILIZESATABOUT ǻBELOWTHENORMALLEVELANDPLASMAVOLUMEDECREASESBYABOUT 3URPRISINGLY TOTALBODYWATER ASMEASUREDUSINGANISOTOPE DILUTIONTECHNIQUE IS UNCHANGED ALTHOUGHTHEEXTRACELLULARʅUIDANDPLASMAVOLUMEAREDECREASED4HESE RESULTSIMPLYTHATTHE,LOSTINTHEVASCULARANDINTERSTITIALCOMPARTMENTOFTHELOWER EXTREMITIESAREPARTIALLYRELOCATEDINTHEINTRACELLULARSPACE!FTERAREDUCTIONINBLOOD VOLUME INCLUDINGLOSSINPLASMAVOLUMEANDREDCELLSCOUNT ANASTRONAUTWILLREACH A NEW STATE OF INTRAVASCULAR HYDRATION THAT WHILE ADAPTED FOR MICROGRAVITY IS PRO FOUNDLYHYPOVOLEMICFOR G

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



!STRONAUTSWEREGIVENANINTRAVENOUSSALINEINFUSIONTOINVESTIGATETHERENALOUTPUT OFSALTANDʅUIDINSPACE4HERATEOFSALTEXCRETIONINSPACEWASTHESAMEASINASITTING POSITIONON%ARTH)NFACT INSPACETHEBLOODPRESSUREISALSOSAMEASWHENSITTINGON %ARTH(OWEVER THECONCENTRATIONLEVELINTHEBLOODOFTHESYMPATHETICNERVOUSSYS TEM HORMONE TRANSMITTER NORADRENALINE WAS SIGNIʄCANTLY INCREASED !N INCREASE IN CARDIACOUTPUTWOULDNORMALLYBEACCOMPANIEDBYLESSSYMPATHETICNERVOUSSYSTEM ACTIVITY WHICHWOULDMEANTHATTHEREISANINCREASEDEXCRETIONOFSALTANDADECREASED RELEASEOFNORADRENALINEINTOTHEBLOODSTREAM4HEUNIQUELUNG HEARTINTERACTIONPRES ENTINMICROGRAVITYMAYBETHESOURCEOFTHISDISCREPANCY)NMICROGRAVITY THETHO RACICCAGEEXPANDSANDLEADSTOANEXPANSIONOFTHECENTRALVESSELSANDTHEHEART4HIS THENCONTRIBUTESTOANINCREASEINBLOODʅOWTOTHEHEART!HIGHERLEVELOFACTIVITY FROMTHESYMPATHETICNERVOUSSYSTEMRESULTS3YMPATHETICACTIVITYCOULDALSORESULT FROMTHEDECREASEINEXTRACELLULARʅUIDVOLUMEINTHELEGS!NEXPERIMENTTOINVESTI GATETHELONG TERMEFFECTSOFMICROGRAVITYONSYMPATHETICNERVOUSSYSTEMACTIVITYIS NOWINPROGRESSONBOARDTHE)33"LOODPRESSUREANDCARDIACOUTPUTAREBEINGMEA SUREDOVER HPERIODSWITHNORADRENALINECONCENTRATIONINTHEBLOODPLATELETSALSO BEINGMEASURED;.ORSKAND+AREMAKER = )TWASALSODISCOVEREDTHATEXPOSURETOMICROGRAVITYIMPAIRSTHEEFʄCIENCYOFTHE BAROREʅEXLOOP!CLOSELYʄTTINGNECKCOLLAR SIMILARTOAWHIPLASHCOLLAR WASUSEDON ASTRONAUTSDURINGTHE3PACELAB3,3 MISSIONTOTESTANDRECORDTWOBLOODPRESSURE SENSINGAREASLOCATEDINTHENECK"YTHEEIGHTHDAYOFʅIGHT ASTRONAUTSHADSIGNIʄ CANTLYFASTERRESTINGHEARTRATES LESSMAXIMUMCHANGEOFHEARTRATEPERUNITOFNECK PRESSURECHANGE ANDASMALLERRANGEOFHEARTRATERESPONSES4HECHANGESTHATDEVEL OPEDWERELARGE STATISTICALLYSIGNIʄCANT ANDOCCURREDINALLASTRONAUTSSTUDIED -EASUREMENTSONHUMANSBEFORE DURING ANDAFTERSEVERALSPACEʅIGHTSHAVEALSO PROVIDED ECHO CARDIOGRAPHIC DATA TAKEN ON CARDIAC DIMENSIONS AND FUNCTION 5LTRASOUNDIMAGINGREVEALEDTHATHEARTVOLUMEINCREASESDRAMATICALLYWHENTHEASTRO NAUTSʄRSTARRIVEINSPACE PROBABLYBECAUSEOFTHEINCREASEDVOLUMEOFBLOODʅOWING INTOTHEHEART&IGURE 4HEHEARTVOLUMETHENSLOWLYDECREASESASTHEASTRONAUTȀS

Figure 4.11. Changes in the Volume of the Left Ventricle Just Before Contraction Prior to, During (FD Flight Day), and After a Spaceflight. Ventricular Filling Increases Early In-Flight and Decreases After a Few Days Relative to Preflight Levels. (Adapted from Lujan and White [1994]).



&UNDAMENTALSOF3PACE-EDICINE

BODYADAPTSTOTHESPACEENVIRONMENT ENDINGUPSMALLERCOMPAREDWITHITSSIZEON %ARTH4HISDECREASEINSIZECANBEEXPLAINEDBYTHEFACTTHATTHEEXCESSOFBLOODAND ʅUIDS HAS BEEN ELIMINATED AND THE HEART DOES NOT NEED TO PUMP THE BLOOD AGAINST GRAVITY)NADDITION PHYSICALWORKREQUIREMENTSAREGENERALLYLESSINSPACE4HEBLOOD VESSELSALSOAPPEARTOBECOMESLIGHTLYSMALLERANDSTIFFER  -AXIMALEXERCISECAPABILITY 7HENTHEASTRONAUTSWEREREQUIREDTOEXERCISEATTHEIRMAXIMALCAPABILITYANDTHEIR CONSUMPTIONOFOXYGEN6/MAX MEASUREDINORBITONBOARDTHE3PACE3HUTTLE THE MEASUREMENTSWERENOTDIFFERENTFROMPREʅIGHT4HISINDICATESTHATTHEMAXIMALCAPAC ITYOFTHECARDIO VASCULARSYSTEM ASREʅECTEDBYMAXIMALEXERCISECAPABILITY WASWELL MAINTAINEDDURINGSHORT DURATIONSPACEʅIGHT#ONSEQUENTLY THELOSSOFʅUIDVOLUME ANDTHEHEARTCHANGESSEEMEDTOREʅECTANORMALADAPTATIONOFTHEHUMANBODYTOAN EXTREMEENVIRONMENTCHANGE4HISADAPTATIONISAPHYSIOLOGICAL RATHERTHANAPATHO LOGICALRESPONSEANDDOESNOTAPPEARTOBEASSOCIATEDWITHIMPAIREDFUNCTION %XERCISE HAS ALSO PROVEN TO BE THE SINGLE MOST EFFECTIVE METHOD FOR REDUCING RE ADAPTATIONEFFECTS SUCHASTHEPOSTʅIGHTORTHOSTATICINTOLERANCE ANDFORMAINTAIN INGAHEALTHYCARDIO VASCULARSYSTEMINSPACE JUSTLIKEON%ARTH&OREXAMPLE ONLYA FEWEXERCISESESSIONSWERESCHEDULEDDURINGTHEʄRSTTWO3KYLABMISSIONS)NTHELATER MISSIONS MORE EXERCISE DEVICES WERE USED AND THE NUMBER OF SESSIONS INCREASED $URINGTHE DAY3KYLAB MISSION SOMEASTRONAUTSACTUALLYIMPROVEDTHEIRCARDIO VASCULARʄTNESS PROBABLYBECAUSETHERIGOROUSEXERCISEREQUIREMENTSOFTHEMISSION EXCEEDEDTHEIRPREʅIGHTTRAININGPRACTICES4HESPACESHUTTLECREWMEMBERSEXERCISE ONCEEVERYSECONDDAYAFTERBEINGONORBITMORETHANDAYS-ORESTRINGENTDAILY PHYSICAL EXERCISE IS SCHEDULED FOR THE )33 CREWMEMBERS WHICH INVOLVES EXERCISE PERIODSOFǻHPERDAYFORDAYS WITHSOMEOPTIONALCHANGEONTHEFOURTHDAY (OWEVER RECENTDATAREVEALALARGEDECLINEINTHEMAXIMALEXERCISECAPABILITYOVER THE ʄRST ǻ DAYS ON BOARD THE )33 &IGURE   4HIS LOSS WHICH TAKES PLACE

Figure 4.12. Left: The Amount of Gas Absorbed by the Lungs and Heart Rate Is Measured During Exercise on a Cycle Ergometer to Determine Cardiac Output and Maximal Oxygen Consumption. (Credit NASA). Right: Changes in Maximal Exercise Capability Relative to Preflight (PRE) Baseline Values During (FD Flight Day) and After (R + Days) ISS Missions. These Data Are from Nine Crewmembers Through ISS Expedition-18 Who Have Performed Exercise Testing in at Least Four Consecutive 50-Day Intervals During Flight. (Adapted from Moore et al. [2010]).

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



DESPITEOFTHECOUNTERMEASURES MAYBERELATEDTOAPHASEOFADAPTATIONOFTHECONTROL MECHANISMS OF THE CARDIO VASCULAR SYSTEM AND THE CHANGES IN BODY ʅUID VOLUMES 3UBSEQUENTIMPROVEMENTISSEENANDBYTHE MONTHMARK MAXIMALEXERCISECAPABIL ITY IS NOT DIFFERENT THAN PREʅIGHT /N THE CONTRARY 6/ MAX IS GENERALLY REDUCED IMMEDIATELYPOSTʅIGHT)TISINTERESTINGTONOTETHATʄTSUBJECTSDEMONSTRATEGENERALLY LARGERREDUCTIONIN6/MAXANDPLASMAVOLUMETHANUNʄTSUBJECTS BOTHIN ʅIGHTAND POSTʅIGHT-AXIMALEXERCISECAPACITYISRESTOREDTOPREʅIGHTLEVELSWITHINAWEEKAFTER SHORT DURATIONSPACEʅIGHT ANDWITHINMONTHAFTERLONG DURATIONSPACEʅIGHT  %XTRAVEHICULARACTIVITY $URINGTHE YEARLIFEOFTHE2USSIAN-IR3PACESTATION TWO PERSON%6!SWERE CONDUCTEDBYCREWMEMBERS-OST%6!SWEREPERFORMEDBETWEENANDDAYS OFSPACEʅIGHT ALTHOUGHSOMEOCCURREDASLATEASǻDAYSOFSPACEʅIGHT!SOF )33%XPEDITION  THEREHAVEBEEN%6!SCONDUCTEDFROMTHE)33 TOTALINGH OF%6!TIME/FTHESE WERECONDUCTEDBYLONG DURATIONCREWMEMBERSWHENTHE SPACESHUTTLEWASNOTDOCKEDTOTHE)334HE%6!SWEREPERFORMEDDURINGTIMEPERI ODSRANGINGFROMTODAYSOFʅIGHT;SOURCEHTTPWWWHQNASAGOVOSF%6! %6!?TOTALS?TABLEHTML= %6!SPERFORMEDFROMTHESPACESHUTTLEAND-IRHAVEELICITEDANAVERAGEMETABOLIC COST OF ABOUT  KCALH OR  , OF OXYGEN PER MINUTE 4HIS REPRESENTS APPROXI MATELYǻOF6/MAXDURINGUPPERBODYEXERCISEOVERPERIODSOFǻH;-OORE ET AL = -EAN METABOLIC RATES OF  KCALH AND ǻ MIN PEAKS OF OVER  KCALHHAVEBEENMEASUREDIN53AND2USSIAN%6!SUITS !STRONAUTSLOSEǻKGMOSTLYʅUIDS DURINGATYPICAL%6!4HESPACESUITIS EQUIPPEDWITHALIQUIDCOOLINGGARMENT WHICHACCOMMODATESTHEHEATPRODUCEDBY THEHIGHWORKLOADREQUIREMENTS(OWEVER OVERCOOLINGOFTHEEXTREMITIESISFREQUENTLY OBSERVED PRESUMABLYBECAUSEOFTHERELATIVEDECREASEINBLOODʅOWINMICROGRAVITY 4HEASTRONAUTCANDRINK USINGASTRAW FROMSMALLCONTAINERSOFLIQUIDSWITHINTHESUIT &AILURETODOSOWOULDRESULTINRAPIDDEHYDRATION4HISISACONCERNBECAUSETHEACUTE DEHYDRATIONCAUSEDBYAN%6!MIGHTAGGRAVATEANALREADYDECONDITIONEDSTATEBROUGHT ONBYEXPOSURETOMICROGRAVITY 4HE LARGE MASS OF THE SUITS WHICH IS ABOUT  KG IS NOT A SIGNIʄCANT ISSUE IN MICROGRAVITY (OWEVER THE WEIGHT OF THE SPACE SUITS IS EXPECTED TO HAVE A GREATER EFFECT ON %6! ACTIVITIES WHEN THE ASTRONAUTS ARE REQUIRED TO AMBULATE MANIPULATE TOOLS AND SCIENTIʄC EQUIPMENT AND CARRY LOADS OF ROCK SAMPLES ON THE -OON AND -ARS$URINGTHE!POLLOMISSIONS WITHASUITMASSOFABOUTKG THEAVERAGEMETA BOLICCOSTOFALUNAR%6!WASABOUTGREATERTHANAMICROGRAVITY%6!(EARTRATES REACHEDǻBEATSMINDURINGSOMEOFTHEACTIVITIES !POLLOASTRONAUTSRECENTLYSTATEDTHATTHEYFELTTHATAPREʅIGHTCONDITIONINGPRO GRAMWASADEQUATEFORSHORTTRIPSTOTHE-OON WHICHLASTEDFORDAYSORLESS STATING THATEXERCISECOUNTERMEASURESARENOTNECESSARYFORSUCHMISSIONS;3CHEURINGETAL =4HELONGESTSTAYONTHE-OONWASDAYS(OWEVER FOREXTENDEDPLANETARY  4HEAUTHORSOFA2USSIANREPORT;0OPOVETAL =REFERREDTOTHEINITIALPHASEOFʅIGHTASAȃDEADPERIODȄ DURINGWHICHTHEDECREASEINPHYSICALCONDITIONISSOSEVERETHATNONEOFTHECOUNTERMEASUREREGIMESARE SUFʄCIENTLYEFFECTIVE



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STAYSITISDIFʄCULTTOPREDICTHOWANASTRONAUTȀSPHYSICALʄTNESSWILLCHANGE)TISNOT KNOWNIF-OONOR-ARSGRAVITYWILLPROVIDEANYPROTECTIONAGAINSTDECREASED6/ MAX WITHOUT ADDITIONAL EXERCISE 0HYSICAL ʄTNESS MAINTENANCE DURING THE TRANSIT TO -ARSWILLALSOBEACONCERN;'ERNHARDTETAL = ! GROUP OF .!3! INVESTIGATORS HAVE INITIATED A SERIES OF PROJECTS TO STUDY THE PHYSIOLOGICAL BIOMECHANICAL ANDSUBJECTIVEASPECTSOFWORKANDEXERCISEINTHEPAR TIALGRAVITYOFTHE-OONAND-ARS4HISISPARTOFANEFFORTTODETERMINETHELEVELSOF CARDIO VASCULAREXERCISECAPACITY STRENGTH ANDCOUNTERMEASUREPROTECTIONTHATWILLBE REQUIREDFOR%6!ACTIVITIESDURINGMISSIONSINVOLVINGLONGSURFACESTAYS4HEMETA BOLICCOSTOFAMBULATIONISMEASUREDWHILEEXERCISINGONATREADMILLINNORMALGRAVITY &IGURE 4HENTHEMEASUREMENTSAREREPEATEDDURINGSIMULATED-OONAND-ARS GRAVITY4HESECONDITIONSAREOBTAINEDUSINGASERVO CONTROLLED PNEUMATICLIFTSYSTEM WITHCONSTANTFEEDBACKFROMASTRAINGAUGETOPROVIDENEARCONSTANTUNLOADING  (EARTRHYTHM )NTHEEARLYPHASEOFTHE53SPACEPROGRAM THEPRESENCEOFIRREGULARHEARTRHYTHM DYSRHYTHMIA WASTAKENASPRESUMPTIVEEVIDENCEOFCARDIACPATHOLOGY!SAMATTEROF FACT THEʄRSTCARDIACGROUNDINGOFANASTRONAUTOCCURREDBECAUSEOFAHEARTRHYTHM DISTURBANCE ;*OHNSON AND $IETLEIN = 4HE PRESENCE OF RHYTHM ABNORMALITIES

Figure 4.13. Astronaut Performing Treadmill Walking in the Mark-III Prototype EVA Suit. Ground-Based Estimates Suggest That, Depending on the Terrain, Walking on the Lunar and Martian Terrain May Be Difficult and Will Likely Require an Above-Average Aerobic Capacity to Accomplish Safely [Moore et al., 2010]. (Credit NASA).

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



D URINGACTUALSPACEʅIGHTCANONLYBEASSESSEDWHENACREWISPHYSIOLOGICALLYMONITORED EG DURINGEXTRA VEHICULARACTIVITY EXERCISE ANDAPPLICATIONOFLOWERBODYNEGATIVE PRESSURE#ONSEQUENTLY THESEHEARTRATEIRREGULARITIESSEEMMOREPREVALENTDURINGTHESE ACTIVITIES 3ERIOUS HEART RHYTHM DISTURBANCES WERE NOTED DURING THE !POLLO PROGRAM BOTH DURING%6!SONTHE-OONANDAFTERRETURNINGTO%ARTH;"ERRY =3OMEOFTHESE ABNORMALITIESHAVEBEENATTRIBUTEDTOELECTROLYTEIMBALANCEORSTRESS&OREXAMPLE THE ASTRONAUTSWEREGIVENEXCESSIVEWORKLOADSONTHE-OONANDHADLOWBLOODPOTASSIUM LEVELSUPONRETURNTO%ARTH 3IGNIʄCANTDYSRHYTHMIASWEREALSOOBSERVEDDURING3KYLAB -IR ANDSHUTTLEʅIGHTS !CREWMEMBERDURINGTHE-IR  MISSIONDEVELOPEDAPERSISTENTDYSRHYTHMIA DURINGAN%6!&IGURE 4HISRESULTEDINTHEMISSIONDURATIONBEINGSHORTENED %ARLIER ON A 3OVIET COSMONAUT WAS RETURNED AHEAD OF SCHEDULE FROM THE 3ALYUT  SPACESTATIONBECAUSEOFANINTERMITTENTCARDIACARRHYTHMIA WHICHORIGINATEDDURING THECOURSEOFAMINORMISHAPDURINGAN%6!4HE2USSIAN3PACE!GENCY23! OR 2OSCOSMOS HAS ALSO REPORTED A COSMONAUT SUFFERING FROM A MASSIVE MYOCARDIAL

Figure 4.14. During the U.S.-Russian Shuttle-Mir Program, Ambulatory ECG Recordings Were Taken on Several Crews. A Recording in One Cosmonaut Revealed a Nonsustained 14-Beat Run of Ventricular Tachycardia. (Adapted from Fritsch-Yelle et al. [1998]).

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INFARCTION AT THE AGE OF  YEARS JUST  YEARS AFTER HIS THIRD SHORT DURATION ʅIGHT -OREOVER THE2USSIANMEDICALCOMMUNITYHASREPORTEDTO.!3!THATOVERTHELAST YEARSOF-IROPERATIONS THEYOBSERVEDAPPROXIMATELYABNORMALELECTROCARDIO GRAMSANDDYSRHYTHMIAS;(AMILTON = !SPREVIOUSLYEXPLAINED THECARDIACATROPHYTHATDEVELOPSDURINGSPACEʅIGHTCOULD LEADTOORTHOSTATICHYPOTENSIONANDABNORMALLEFTVENTRICULARFUNCTION3UCHATROPHY MAYALSOBEATTHEROOTOFTHEIRREGULARHEARTRHYTHMSOBSERVEDINSOMEOFTHE-IR CREWMEMBERS AFTER LONG DURATION EXPOSURE TO MICROGRAVITY ! SIGNIʄCANT LIMITING FACTOR FOR EXTENDED DURATION SPACE EXPLORATION MISSIONS MAY BE CARDIAC ATROPHY ACCORDINGTOTHERESULTSOFRECENTSIMULATIONSTUDIESTHATSUGGESTTHATTHISCONDITION MAYBEPROGRESSIVE ANDWITHOUTACLEARPLATEAUOVERATLEASTWEEKS4HEGOALOF ANOTHERONGOING)33EXPERIMENTISTOIDENTIFYTHEMECHANISMSOFCARDIACATROPHYAND QUANTIFY ITS EXTENT TIME COURSE AND CLINICAL IMPLICATIONS DURING PROLONGED SPACE ʅIGHT)NADDITION THEFUNCTIONALCONSEQUENCESOFCARDIACATROPHY BOTHINSPACEAND FOLLOWINGRETURNTO%ARTH WILLBEDETERMINEDFORORTHOSTATICTOLERANCEUNDER%ARTH -ARS AND-OONGRAVITYCONDITIONSCARDIACʄLLINGDYNAMICSEXERCISETOLERANCEAND ARRHYTHMIASUSCEPTIBILITY)NʅIGHT ADVANCEDECHO $OPPLEREXAMINATIONSWILLBEUSED TODETERMINEHOWHEARTMUSCLEATROPHYINʅUENCESTHEWAYTHEHEARTRELAXESANDʄLLS /N THE GROUND MAGNETIC RESONANCE IMAGING -2) OF THE HEART PERFORMED BOTH BEFOREANDAFTERTHEʅIGHT WILLPINPOINTWHATKINDOFATROPHYOCCURSANDPRECISELY QUANTIFYITSEXTENT;,EVINEAND"UNGO = 

0OSTʅIGHT

!SMENTIONEDINTHEPREVIOUSSECTIONS THERE ENTRYFORCESINTHE3OYUZCAPSULESCAN GOUPTOGEXERTEDALONGTHE'XAXISCHESTTOBACK 4HEPOSITIONTHEMOSTEFFEC TIVEFORG TOLERANCE LYING ON BACKWITHTHELEGSʅEXED WASCHOSENBECAUSETHENEED FORTHECOSMONAUTTOȃʅYȄTHEVEHICLEISMINIMAL&IGURE "YCONTRAST THEASTRO NAUTSINTHESPACESHUTTLEAREEXPOSEDTORE ENTRYFORCESALONGTHE'ZAXISHEAD TO TOE DUETOTHEGLIDINGATTITUDEOFTHEVEHICLE4HESEFORCESDONOTEXCEEDǻG FORAPPROXIMATELYMIN(OWEVER SUCHSMALLFORCESDURINGRE ENTRYAFTERDAYS OFCARDIO VASCULARDECONDITIONINGINMICROGRAVITYMAYBEASPROVOCATIVEASFORCESOF ǻ G IN A ʄGHTER AIRCRAFT WITH A ʄT PILOT )N THE WORST CASE LOSS OF CONSCIOUSNESS SYNCOPE MAYRESULTFROMADECREASEINBLOODʅOWTOTHEBRAINCEREBRALHYPOPERFU SION SEE4ABLE  "OTHTHEHEARTRATEANDARTERIALPRESSUREINCREASEDURINGRE ENTRYANDJUSTAFTERLAND ING&IGURE !FTERLANDING ALLʄRST TIMEASTRONAUTSARETESTEDFORTHEDEGREEOF THEIRINTOLERANCEEITHERBYLAYINGTHEMONAȃTILTTABLEȄTHATMOVESRAPIDLYFROMTHE HORIZONTALTOVERTICALPOSITION ORBYCOMPARINGTHEIRHEARTRATESANDBLOODPRESSURES BETWEENSUPINERESTANDUPRIGHTSTANDING!FTERSHORT DURATIONSPACEʅIGHTABOUT OFCREWMEMBERSAREUNABLETOCOMPLETEA MINSTANDTESTONLANDINGDAY ANDARE FORCEDTOSITDOWNTOPREVENTSYNCOPE4HECAUSESFORTHISORTHOSTATICINTOLERANCEARE

 $URINGTHE)33%XPEDITION CREWRETURNIN-AY THE3OYUZHEADEDDOWNATASTEEPERANGLE THUS DECELERATINGFASTERTHANPLANNED!SARESULT THECREWWASSUBJECTEDTOǻGFORSEVERALMINUTES

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



Figure 4.15. Tolerance to Acceleration, Measured as the Time Before Fainting During a Run in a Centrifuge in Various Body Positions. Tolerance Is Stronger in the Supine or Prone Than in the Upright Position Due to the Effect of Acceleration on the Column of Blood.

Figure 4.16. Changes in Heart Rate and Arterial Pressure When Going from the Seated to a Standing Position Preflight and Postflight, and During Re-entry and Landing (0-g to Touchdown). When Standing Postflight, Despite an Increase in Heart Rate, There Is a Decrease in Arterial Pressure, Which Can Lead to Pre-syncope or Syncope. (Adapted from Sawin et al. [1998]).

DIVERSE )N SOME SUBJECTS THE SYNCOPE IS DUE TO A DECREASED BLOOD ʅOW LESS THAN M,MINPERGOFBRAINTISSUE INOTHERSITISDUETOADECREASEDARTERIALPRESSURE MEANARTERIALPRESSURELESSTHANMM(G  ! VERY EVIDENT CARDIAC RESPONSE POSTʅIGHT IS A MARKEDLY ELEVATED HEART RATE &IGURE 4HISISPROBABLYAREʅEXIVEACTIONTOINCREASECARDIACOUTPUTAND THUS BLOODPRESSURE4HISINCREASEDHEARTRATESEEMSESPECIALLYIMPORTANTTOCARDIO VASCULAR FUNCTION AS TESTS HAVE SHOWN THAT OTHER MECHANISMS TO INCREASE SHORT TERM BLOOD



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PRESSURE LIKE INCREASING PERIPHERAL RESISTANCE OR INCREASING STROKE VOLUME THROUGH INCREASEDHEARTCONTRACTILITY VIATHESYMPATHETICNERVOUSSYSTEMSEEMLESSEFʄCIENT AFTERSPACEʅIGHT$ECREASEDBARORECEPTORSENSITIVITYACQUIREDINMICROGRAVITYCANALSO SLOWTHETOTALRESPONSE 2ECENT STUDIES PERFORMED ON SIX ASTRONAUTS BEFORE AND AFTER LONG DURATION ǻDAYS SPACEʅIGHTSREVEALEDTHATORTHOSTATICINTOLERANCEISEVENMORESEVERE AFTERLONG DURATIONTHANAFTERSHORT DURATIONʅIGHT&IVEOFTHESIXASTRONAUTSSTUDIED BECAMEPRE SYNCOPALDURINGTILTTESTINGAFTERLONG DURATIONʅIGHTS WHEREASONLYONE HADBECOMEPRE SYNCOPALDURINGSTANDTESTINGAFTERSHORT DURATIONʅIGHTS;-ECKETAL =

 7HATDOWEKNOW  /RTHOSTATICINTOLERANCE 0OSTʅIGHT ORTHOSTATIC INTOLERANCE IS A RESULT OF MORE THAN JUST THE LOSS OF ʅUID /RTHOSTATICINTOLERANCEISPRESUMABLYCAUSEDBYTHREEFACTORSTHATARERELATEDTOEACH OTHERTHEVOLUMEOFBLOODINTHEBLOODVESSELS THEABILITYOFBLOODVESSELSTOEXPAND ORCONSTRICTTOMAINTAINBLOODPRESSURE ANDTHEFUNCTIONINGOFTHEHEARTITSELF7EHAVE ALREADYSEENTHATUPONRETURNTO%ARTH WHENGRAVITYPULLSTHEʅUIDDOWNWARDAND THEREISNOTENOUGHʅUID THESYSTEMCANNOTFUNCTIONNORMALLYANDTHISCONTRIBUTESTO THEOCCURRENCEOFORTHOSTATICHYPOTENSION&IGURED  !NOTHERCONTRIBUTORTOTHISPROBLEMISTHEAUTONOMICNERVOUSSYSTEM WHICHHELPS CONTROLBLOODPRESSURE AMONGOTHERTHINGS.ORMALLY THISSYSTEMISRESPONSIBLEFOR MAKINGMINUTEANDIMMEDIATEADJUSTMENTSTOTHECARDIO VASCULARSYSTEMTOMAINTAIN BLOODʅOWANDPRESSUREDURINGCHANGESINPOSTURE4HESYSTEMDOESTHISBYRELEASING ANEUROTRANSMITTERCALLEDNOREPINEPHRINETHATCAUSESTHEBLOODVESSELSTOCONSTRICTTO KEEPTHEPRESSUREATTHEAPPROPRIATELEVELTOSUPPLYANADEQUATEAMOUNTOFBLOODTOTHE BODYȀSORGANS)NSPACE WHENHYDROSTATICGRADIENTSAREREMOVED SUCHASCHANGING FROM THE UPRIGHT TO THE SUPINE POSITION PERHAPS THOSE MECHANISMS ȃFORGETȄ THEIR FUNCTION 2ESEARCH ON ANIMALS HAS UNDERLINED THE IMPORTANCE OF THE BARORECEPTORS IN THE REGULATION OF BLOOD PRESSURE $OGS WHOSE CAROTID SINUS BARORECEPTORS HAVE BEEN EXCISEDHAVEAVARIATIONOFFROMTOINTHEIRMEANBLOODPRESSURE-ANUALCOM PRESSIONOFCAROTIDSINUSESCANCAUSESYNCOPEANDBRADYCARDIA ORLOWHEARTRATEINA HEALTHYPERSON)NMICROGRAVITY HOWEVER THECAROTIDSINUSWOULDʄRENERVEIMPULSES ATAMOREORLESSCONSTANTRATE4HEEXTENTTOWHICHTHESENSITIVITYOFTHEBARORECEPTORS MAYDECREASEWITHPROLONGEDSPACEʅIGHT ANDTHEIRABILITYTOREGAINTHELOSTSENSITIVITY ISUNKNOWN /RTHOSTATIC HYPOTENSION IS ALSO CAUSED BY THE BLOOD VESSELS 4HE VESSELS THEM SELVESHAVEACERTAINAMOUNTOFCONTROLOVERTHEAMOUNTOFBLOODʅOWINGTOTHEORGAN THEY ARE SERVING &OR EXAMPLE WHEN A BLOOD PRESSURE CUFF IS INʅATED TO THE POINT WHERETHEREISNOBLOODʅOWTHROUGHTHEVESSELSOFTHEARM THEARMȀSVESSELSDILATETO TRYTOINCREASETHEʅOWRATE)FTHECUFFISSUDDENLYRELEASED THEDILATEDVESSELSALLOW THEBLOODTORUSHBACKINTOTHEARM4HISINCREASESSHEARSTRESS WHICHACTUALLYSTIMU LATESTHELININGOFTHEBLOODVESSELSTORELEASEADDITIONALVASODILATORS ENSURINGTHATTHE

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



ARMWILLRECEIVEINCREASEDBLOODʅOW4HISMECHANISMISCALLEDREACTIVEHYPEREMIA 3IMILARLY WHENANASTRONAUTRETURNSTO%ARTHANDBLOODRUSHESTOHISHERLEGS THEVES SELS MIGHT RESPOND NOT BY CONSTRICTING TO FORCE THE BLOOD BACK UP BUT BY DILATING FURTHER WHICHPERMITSMOREʅOWDOWNWARDANDLESSPRESSURE RESULTINGINLESSBLOOD INTHEASTRONAUTȀSUPPERBODYANDHEAD(ENCE THEYFAINT !NOTHER TREND OBSERVED IN RECENT STUDIES IS THAT THERE IS A DIFFERENCE BETWEEN WOMENANDMENINTHEABILITYOFTHEIRBODIESTOMAINTAINBLOODPRESSUREAFTERSPACE ʅIGHT7OMENGENERALLYHAVEAHIGHERHEARTRATEANDALOWERVASCULARRESISTANCETHAN DOMEN4HUS WHENFEMALEASTRONAUTSRETURNFROMSPACE THEIRVASCULARRESISTANCE ALREADYLOW ISINSUFʄCIENTTOCOMBATTHELOWERBLOODVOLUME)NARECENTPOSTʅIGHT ANALYSISAFTERASHORT DURATIONSPACEʅIGHT ALLFEMALEASTRONAUTSBECAMESYNCOPALVER SUSONLYOFMALEASTRONAUTS;(ARMETAL = !GING MIGHT ALSO BE A FACTOR 4HE DIFFERENCES THAT AGING HAD MADE TO HIS BODY BETTEREQUIPPED*OHN'LENN ATAGE TOHANDLETHECARDIO VASCULARADAPTATIONSTOA MICROGRAVITYENVIRONMENT&IGURE 7HENHERETURNEDFROMORBIT FARFROMFEEL INGFAINTORSUFFERINGFROMCARDIO VASCULARSTRESS HEWASCALMANDSTOODUPRIGHTWITH NOPROBLEM!NOLDERPERSONHASADIFFERENTSTRATEGYTHANAYOUNGPERSONINMAINTAIN INGBLOODPRESSURE'LENNHADAHIGHRELEASEOFNOREPINEPHRINE WHICHHELPEDTOMAIN TAINHISBLOODPRESSURE BOTHBEFOREANDAFTERSPACEʅIGHT4HISRESPONSEISTYPICALOF THEELDERLYANDFOR'LENN THISRESULTEDINANORMALLEVELOFVASCULARRESISTANCE'LENN ALSO HAD A HIGHER CARDIAC OUTPUT THAN THE OTHER MALE ASTRONAUTS POSSIBLY DUE TO A GREATERVENOUSRETURN4HISHIGHEROUTPUTCOUPLEDWITHANORMALVASCULARRESISTANCE

Figure 4.17. John Glenn Returned to Space on Shuttle Mission STS-95 at Age 77, i.e., 37 years After His First Flight on Board Mercury. His Cardio-Vascular Response Was Closely Monitored to Study the Effects of Aging on the Ability of the CardioVascular System to Adapt to Spaceflight. (Credit NASA).

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PRESUMABLY ENABLED 'LENN TO MAINTAIN AN ADEQUATE BLOOD PRESSURE ON LANDING DAY ;2OSSUMETAL = &INALLY ALTHOUGH THERE IS EVIDENCE THAT BOTH THE AUTONOMIC NERVOUS SYSTEM AND HORMONESECRETIONAREALTERED THEIREFFECTSONTHEKIDNEYS BLOODVESSELS ANDHEART HAVEYETTOBEFULLYUNDERSTOODANDMUSTBESTUDIEDOVERVARYINGDURATIONOFEXPOSURE TOWEIGHTLESSNESS%LUCIDATIONOFTHEMECHANISMSOFTHESEEFFECTSPROMISESTOSHED LIGHTONSOMECLINICAL NON SPACEʅIGHTPROBLEMSSUCHASHIGHBLOODPRESSUREANDHEART FAILURE )NSUMMARY HYPOVOLEMIA CARDIACATROPHY ANDAUTONOMICDYSFUNCTIONHAVEEACH BEENHYPOTHESIZEDTOCONTRIBUTETOPOSTʅIGHTORTHOSTATICINTOLERANCE BUTTHEIRRELATIVE IMPORTANCEISUNCLEAR&URTHERMORE ITISUNKNOWNWHETHERACTUALABNORMALITIESINTHE MYOCARDIUMITSELFDEVELOPWITHLONG DURATIONSPACEʅIGHT4HEREFORE RELIABLEPORTA BLENONINVASIVEMETHODSARENEEDEDTODETECTANDQUANTIFYTHESECHANGES4HEIMAG ING MODALITIES OF RADIOGRAPHY MAGNETIC RESONANCE IMAGING AND COMPUTERIZED TOMOGRAPHYWOULDBESTATE OF THE ARTTECHNIQUES!SPECIALLYMODIʄEDCOMMERCIAL ULTRASOUNDECHOCARDIOGRAPHINSTRUMENTISBEINGUSEDINTHE(UMAN2ESEARCH&ACILITY OF THE )33 FOR MEDICAL DIAGNOSIS AND PHYSIOLOGY RESEARCH &IGURE   4O DATE ECHOCARDIOGRAPHYHASTHEMOSTVERSATILEABILITYTOCHARACTERIZECARDIO VASCULARANAT OMYANDPHYSIOLOGYINGROUND BASEDMODELS PRE ANDPOSTʅIGHT ANDMOSTIMPOR TANTLYDURINGʅIGHT;-ARTINETAL = 

0ULMONARYFUNCTION

4HEPULMONARYSYSTEMWORKSINTANDEMWITHTHECARDIO VASCULARSYSTEMTOSUPPLYTHE BODYWITHTHEOXYGENNEEDEDFORLIFE5NLIKETHECARDIO VASCULARSYSTEM NOPULMO NARYSYSTEMPROBLEMSHAVEBEENASSOCIATEDWITHWEIGHTLESSNESSPERSE ANDRESEARCH ERSHAVEDEVOTEDLESSATTENTIONTOITSPHYSIOLOGYINMICROGRAVITY)NFACT ANINCREASED LUNGBLOODʅOWANDMOREUNIFORMʅOWDISTRIBUTIONWEREOBSERVEDINMICROGRAVITY SUGGESTING THAT OVERALL LUNG FUNCTION WAS ACTUALLY IMPROVED IN SPACE ;7EST ET AL =(OWEVER INTHELONGTERM LUNGFUNCTIONCANBEALTEREDBYCHANGESINVASCULAR PRESSUREANDVOLUME!LSO ITISPOSSIBLETHATLENGTHYALTERATIONSINTHERELATIVEʅOW DISTRIBUTIONOFBLOODANDAIRINDIFFERENTLUNGREGIONSMIGHTPERMANENTLYAFFECTRIGHT HEARTFUNCTION;,INNARSSON =$YSBARISM THECONDITIONTHATRESULTSFROMEXPO SURE TO DECREASED OR CHANGING BAROMETRIC PRESSURE IS ALSO A PROBLEM OF INCREASING MAGNITUDEDURINGEXTRA VEHICULARACTIVITYSEE#HAPTER 3ECTION  !LONGWITHALTERATIONSRESULTINGFROMCHANGESINVASCULARPRESSURESANDVOLUMES INHALEDGASES VAPORS ANDAEROSOLSCANDAMAGETHELUNGS)NTEGRITYOFTHEPULMONARY SYSTEMCANNOTBEASSUMEDSIMPLYBECAUSEOFLACKOFSYMPTOMSOROVERTCLINICALSIGNS 4HEFACTORSAFFECTINGTHESELECTIONOFCABINATMOSPHERESANDPRESSURESFORSPACEʅIGHT ASWELLASTHEPROBLEMSOFCABINATMOSPHEREMAINTENANCEANDCONTAMINATIONINOPENOR CLOSEDENVIRONMENTALSYSTEMSWILLBEDISCUSSEDLATERSEE#HAPTER 3ECTION  4HEKIDNEYSARECENTRALTOTHEABOVE MENTIONEDPHYSIOLOGICQUESTIONS2ENALPROB LEMS MAY OCCUR IN THE SPACE ENVIRONMENT !S WE WILL SEE IN THE NEXT CHAPTER SEE #HAPTER 3ECTION WEIGHTLESSNESSCAUSESAMONTHLYRESORPTIONOFBONE CALCIUM WHICHISEXCRETEDINTHEURINE7ITHINCREASEDCONCENTRATIONOFURINARYCAL CIUMANDSOMEOTHERCHANGESINDUCEDBYWEIGHTLESSNESS SUCHASURINEALKALINITYAND

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



POSSIBLEREDUCTIONINURINEVOLUME KIDNEYSTONESMAYFORMMOREEASILY)NADDITION TO DEBILITATING PAIN KIDNEY STONES MIGHT OBSTRUCT THE URINARY TRACT AND PRECIPITATE INFECTION WHICHISPOTENTIALLYQUITEDANGEROUSINSPACE4HUS KIDNEYFUNCTIONMUST BE UNDERSTOOD BETTER WITH REGARD TO CALCIUM METABOLISM AS WELL AS ITS RELATION TO CARDIO VASCULARPHENOMENA 7EALSOSTILLNEEDTOUNDERSTANDMORECOMPLETELYTHEACTIONSOFDRUGSTHATAFFECT CARDIO PULMONARY AND RENAL SYSTEMS IN SPACE 4HIS WILL BE ESSENTIAL FOR ADEQUATE HEALTHMAINTENANCE/RDEREDINDESCENDINGPRIORITY THEFOLLOWINGCLASSESOFAGENTS MUST BE INVESTIGATED ANTI ARRHYTHMICS BRONCHODILATORS ANTI ALLERGY AND ANTI ANAPHYLACTIC DRUGS ANALGESICS INCLUDING NARCOTICS HYPNOTICS AND PSYCHOTROPICS DIURETICS ANDANTI COAGULANTS 

"EDREST

3INCETHEBEGINNINGOFTHESPACEPROGRAM HUMANBEDRESTHASBEENCOMMONLYUSEDAS AGROUND BASEDMODELTOTESTTHEEFFECTSOFWEIGHTLESSNESSANDPROPOSEDCOUNTERMEA SURESUPONTHECARDIO VASCULARSYSTEM)NTHISMODELRESEARCHSUBJECTSAREREQUIREDTO REMAININBEDFORLENGTHSOFTIMEFROMAFEWDAYSTOSEVERALMONTHS4HEBEDISTILTED ATmHEAD DOWN SOTHATHEADISBELOWTHEHEART4HISTILTPOSITIONSIMULATESTHESAME ʅUIDSHIFTASINMICROGRAVITY,UNARAND-ARTIANGRAVITYMAYALSOBESIMULATEDWITHA BEDTILTOFmANDmRELATIVETOTHEHORIZONTAL THUSSIMULATINGAGRAVITATIONALLOAD OFANDG RESPECTIVELY ALONGTHEMAINCOLUMNOFBLOOD&IGURE  )NFACT STUDIESHADBEENCONDUCTEDONBEDRESTPATIENTSANDONNORMAL HEALTHY SUBJECTS STARTING AS EARLY AS  0HYSICIANS HAVE USED PROLONGED REST IN BED TO IMMOBILIZE AND CONʄNE PATIENTS FOR REHABILITATION AND RESTORATION OF HEALTH EVEN BEFORETHATTIME4HERATIONALEISTHATTHEHORIZONTALPOSITIONRELIEVESTHESTRAINOFTHE UPRIGHT POSTURE ON THE CARDIO VASCULAR SYSTEM BONE FRACTURES MUSCLE INJURIES OR FATIGUE#ONSEQUENTLY THEREISANALMOSTCOMPLETELOSSOFHYDROSTATICPRESSURESEE &IGURE  VIRTUAL ELIMINATION OF LONGITUDINAL COMPRESSION OF THE SPINE AND LONG

Figure 4.18. Subjects Are Lying in Bed for Duration Ranging From 5 Days to 3 Months to Simulate the Effects of Microgravity (left) or Lunar Gravity (right) on the Cardio-Vascular System Responses. (Credit National Space Biomedical Research Institute (NSBRI)).



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BONESOFTHELOWEREXTREMITY ANDREDUCEDMUSCULARFORCE0ATIENTSONPROLONGEDBED RESTEXPERIENCEHEADWARDʅUIDSHIFT DECREASEINBLOODPRESSUREANDBLOODVOLUME ANDREDUCEDPHYSICALACTIVITYSIMILARTOTHOSETHATOCCURINASTRONAUTSINSPACE;'HARIB AND#USTAUD = "EDRESTSTUDIESWERETHEʄRSTTOINDICATETHATBARORECEPTORREʅEXESMAYBEIMPAIRED WITHTIME)NEFFECT WHENCONTINUOUSLYEXPOSEDTOINCREASEDPRESSURE THEBARORECEP TORS APPARENTLY BECOME LESS SENSITIVE AND RESPONSIVE ;%CKBERG AND &RITSCH = 3IMILARʄNDINGSHAVELATERBEENFOUNDDURINGSPACEʅIGHT4HESECHANGESINSENSITIVITY ANDRESPONSIVENESSMAYTAKEDAYSTOOCCURAND SIMILARLY MAYTAKESEVERALDAYSTO READJUST UPON RETURN TO %ARTH /NGOING STUDIES ARE BEING CONDUCTED TO VERIFY THESE RESULTS &OLLOWINGABEDREST VOLUNTEERSAREMONITOREDWHILEPLACEDSUPINEONATILTTABLE ANDSUDDENLYBROUGHTUPRIGHT&IGURE 'ETTINGUPRIGHTAGAINAFTERMONTHSIN THEHORIZONTALPOSITIONEVIDENTLYHASITSCOST
%VENAFTERAFEWDAYSINBEDMOSTPEOPLE EXPERIENCEPROBLEMSWITHBALANCEANDDIZZINESS!FTERMONTHSINBEDTHESAMEAND MORE EXPRESSED PROBLEMS SUCH AS ORTHOSTATIC HYPOTENSION ARE OBSERVED 3UBJECTS NEED CONSIDERABLE TIME BEFORE THEY CAN STAND AND WALK WITHOUT ASSISTANCE 2EHABILITATION ACTIVITIES ARE THEN BEING EVALUATED .ORMALLY MOST PROBLEMS WITH STANDINGANDWALKINGAREOVERWITHINAFEWDAYS AFTERWHICHTHEREBUILDINGOFMUSCLE STRENGTHCANBEGIN4HEFULLRECOVERYOFMUSCLEANDINPARTICULARBONETISSUEMAYTAKE MUCHLONGER UPTOMONTHS ALTHOUGHNOTNECESSARILYBEINGFELTBYTHEINDIVIDUAL 4HE STUDENTS OF THE )NTERNATIONAL 3PACE 5NIVERSITY HAVE PROPOSED AN IDEA OF EXPOSINGCREWMEMBERSRETURNINGFROMA MONTHMISSIONONBOARDTHE)33TOABED RESTOFǻMONTHSSIMULATING-ARSGRAVITY&OLLOWINGTHISBEDRESTTHECREWMEMBERS

Figure 4.19. At the End of a Bed Rest Study, the Volunteers Are Placed on a Motorized Tilt Table. Their Cardio-Vascular Responses Are Measured When They Are Passively Moved from a Supine to an Upright Posture. (Credit MEDES).

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



WOULDBESENTFORANOTHER MONTHTOUROFDUTYONBOARDTHE)33;3METETAL = 4HEPROPOSEDSTUDY CALLED-ARTIAN&EELING ISADRESSREHEARSALOFAMISSIONTO-ARS AIMEDATSIMULATINGTHELONG DURATIONEFFECTSOFANDGONTHECARDIO VASCULAR SYSTEM EVALUATINGTHECARDIACTOLERANCEANDEXERCISECAPABILITY ANDVALIDATINGPOTEN TIALCOUNTERMEASURESANDANINTEGRATEDTRANSITSIMULATION

 #OUNTERMEASURES 2ESEARCHERS REMAIN CONCERNED ABOUT DEVISING AND REʄNING COUNTERMEASURES TO PREVENTORAVOIDCARDIO VASCULARPROBLEMSASSOCIATEDWITHTHERETURNFROMMICROGRAV ITYTO%ARTHȀSGRAVITY!SDISCUSSEDPREVIOUSLY THECARDIO VASCULARPROBLEMSASSOCI ATED WITH SPACEʅIGHT ARE MULTIFACTORIAL &OUR OR ʄVE DIFFERENT COUNTERMEASURES IN SOMECOMBINATIONWILLPROBABLYBENEEDEDTOSOLVETHEPROBLEMCOMPLETELY#URRENT COUNTERMEASURES INCLUDE PREʅIGHT AND IN ʅIGHT EXERCISE APPLICATION OF LOWER BODY NEGATIVEPRESSURE,".0 IN ʅIGHT ʅUIDLOADINGPRIORTORE ENTRY ANDREHABILITATION AFTERRETURNTO%ARTH 

)N ʅIGHT

 %XERCISE !SARULE CREWMEMBERSAREENCOURAGEDTODRINKADEQUATEAMOUNTSOFʅUIDSANDTO MAINTAINAREGULAREXERCISESCHEDULE%XERCISEHASAPROTECTIVEEFFECTONTHEINCREASE INHEARTRATEANDFALLINBLOODPRESSUREDURINGSTANDINGAFTERʅIGHT/NEWAYTOPREVENT HARMFULEFFECTSOFCARDIO VASCULARDECONDITIONINGISTOSTARTTHESPACEʅIGHTATAHIGHER LEVELOFCONDITIONINGBYATHLETICTRAININGBEFORETHEʅIGHT-ANYOFTHEASTRONAUTSRUN JOG ORPARTICIPATEINAEROBICEXERCISEASPARTOFTHEIRDAILYROUTINETRAINING !NAGGRESSIVEIN ʅIGHTAEROBICEXERCISEPROGRAMSEEMSTOBEPARTIALLYEFFECTIVEIN MAINTAINING POSTʅIGHT AEROBIC CAPACITY BUT ITS EFFECTS ON ORTHOSTATIC TOLERANCE ARE LARGELYUNKNOWN)TISIMPORTANTTONOTETHATTHEDISCUSSIONOFEXERCISEASACOUNTER MEASUREHEREISAIMEDATCARDIO VASCULARCONDITIONING/THERTYPESOFEXERCISEIE RESISTANCETRAINING CANALSOBEIMPORTANTASCOUNTERMEASURESFORSKELETALANDBONE LOSSSEENINMICROGRAVITYSEE#HAPTER 3ECTION  3PECIALRESTRAINTSYSTEMSLIKEBUNGEECORDSAREREQUIREDTOHOLDTHEASTRONAUTSIN PLACEDURINGEXERCISESESSIONS!NOTHERPRACTICALISSUEREGARDINGEXERCISEINSPACEIS THATITGENERATESVIBRATIONSTHATARETRANSMITTEDTHROUGHTHESTRUCTUREOFTHESPACECRAFT AND MIGHT IMPACT EXPERIMENTS REQUIRING VERY LOW GRAVITY LEVELS !LSO THERE IS NO SHOWER
&OR)33CREWMEMBERS THEDURATIONOFREQUIREDEXERCISETOBALANCEMISSIONNEEDS ANDACHIEVABLECARDIO VASCULARCONDITIONINGREMAINSDEBATED%XERCISESESSIONSTYPI CALLYLASTHPERDAY INCLUDINGTIMETOCHANGEINTOEXERCISECLOTHINGANDCLEANUP FOLLOWINGACTIVITY SOTHEEFFECTIVEDAILYEXERCISETIMEISAPPROXIMATELYH4HESE SESSIONSINCLUDETRAININGONTREADMILL CYCLEERGOMETERS&IGURE ANDRESISTIVE EXERCISEDEVICES4OSUPPORTAEROBICTRAINING THE53CREWMEMBERSTYPICALLYPER FORMFOURTOSIXSESSIONSPERWEEKFORǻMINEACHUSINGTHETREADMILL ANDTWOTO THREESESSIONSPERWEEKFORǻMINUSINGTHECYCLEERGOMETER!EROBICEXERCISEIS



&UNDAMENTALSOF3PACE-EDICINE

Figure 4.20. These Photographs Show Crewmembers Exercising on the U.S. and Russian Treadmills and Cycle Ergometers, Which Are Located in the Destiny and the Zvezda Modules of the ISS, Respectively. (Credit NASA).

USUALLYATǻOFMAXIMALHEARTRATE WITHTREADMILLRUNNINGATLESSTHANONEFULL BODYWEIGHTOFRESISTANCE;%NGLISHETAL = 7HILEEXERCISING THE2USSIANCOSMONAUTSSOMETIMESUSETHIGHCONSTRICTIONCUFFS TODECREASEHEADWARDʅUIDSHIFT$ATAONTHEEFFECTIVENESSOFTHESECUFFSARELACKING BUT MANY COSMONAUTS REPORT SIGNIʄCANT RELIEF FROM THE HEAD CONGESTION AND FACIAL EDEMAOTHERWISEASSOCIATEDWITHMICROGRAVITY;(ERAULTETAL = )TISPERHAPSSURPRISINGTHAT TODATE WEHAVEVERYLITTLEUNDERSTANDINGOFTHEEXACT PHYSIOLOGICEFFECTSBENEʄCIALORHARMFUL OFVARIOUSTYPESOFEXERCISEONTHEPHE NOMENON OF CARDIO VASCULAR DECONDITIONING &OR EXAMPLE SOME EVIDENCE SUGGESTS THATTHEAEROBICALLYTRAINEDINDIVIDUALMAYBEMOREVULNERABLETOORTHOSTATICINTOLER ANCE0ROTOCOLSFORPREʅIGHT IN ʅIGHT ANDPOSTʅIGHTEXERCISEMUSTBEDESIGNEDAND TESTEDINARIGOROUSMANNERTODETERMINEWHAT IFANY TYPESOFEXERCISEMAYBETHE BESTCOUNTERMEASURESTODECONDITIONING)NTEGRATEDINTOTHEPROBLEMOFUNDERSTANDING THE EFFECTS OF EXERCISE ON CARDIO VASCULAR DECONDITIONING IS ALSO UNDERSTANDING THE RESPONSESOFBLOODGASES ELECTROLYTES GLUCOSE INSULIN GROWTHHORMONE GLUCAGON ANDCORTISOL  ,OWERBODYNEGATIVEPRESSURE !LOWERBODYNEGATIVEPRESSURE,".0 OR#HIBIS ISADEVICETHATENCLOSESTHELOWER ABDOMENANDLOWEREXTREMITIESTOMAINTAINACONTROLLEDPRESSUREDIFFERENTIALBELOW AMBIENT&IGURE 4HISDEVICEISUSEDINCONJUNCTIONWITHHEARTRATEANDBLOOD PRESSUREMONITORINGCAPABILITIES)TPROVIDESACONTINUOUSDECOMPRESSIONANDMAINTE NANCEOFȪMM(G$ECOMPRESSIONFROMAMBIENTPRESSURETOȪMM(GCANRANGE FROMSTOMINIE RAPIDTOSLOWDECOMPRESSION (OWEVER CAREISTAKENINTHIS

)TISINTERESTINGTONOTETHATRESEARCHLITERATUREOVERWHELMINGLYSHOWSTHEGREATESTBENEʄTSINMARKERSOF CARDIO RESPIRATORYʄTNESSAREREALIZEDWITHHIGHERINTENSITYǻ LOWERDURATIONEXERCISEPROTOCOLS SUCHASINTERMITTENTORINTERVALPROGRAMSCOMBININGSHORTSPRINTSWITHSHORTTOMEDIUMRESTPERIODSFORA WIDE VARIETY OF POPULATIONS RANGING FROM HEART DISEASE PATIENTS TO ENDURANCE ATHLETES ;-IDGLEY AND -C.AUGHTON =



4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



Figure 4.21. Left: A Lower Body Negative Pressure (LBNP) Device Causes the Intravascular Volume to Shift Towards the Lower Extremities in Microgravity, in a Manner Similar to the Orthostatic Load Caused by Assuming an Upright Posture in Earth’s Gravity. (Credit Philippe Tauzin). Right: The Russian Chibis Suit. (Credit NASA).

APPROACHBECAUSE IFDECOMPRESSIONISTOOFAST SIMILAREFFECTSTOPOSTʅIGHTORTHOSTATIC INTOLERANCECANOCCUR!NADJUSTABLEFOOTSUPPORT REMOVABLESADDLE ANDKNEEʄXATION WITHINTHEDEVICEPROVIDESSKELETALȃLOADEDȄANDȃUNLOADEDȄ,".0 !SINSTANDING THECARDIO VASCULARSYSTEMRESPONDSTO,".0BYINCREASINGBLOOD PRESSURETOMAINTAINʅOWTOTHEUPPERBODYANDHEAD,".0TESTSPERFORMEDON ORBIT PROVOKEALARGERINCREASEINLEGVOLUMES ASʅUIDISSHIFTEDRAPIDLYFOOTWARD THANIN CONTROLTESTSON%ARTH4HEREISALSOAMUCHLARGERINCREASEINHEARTRATE TOMAINTAIN UPPER BODYBLOODPRESSURE THANON%ARTH4HESERESULTSMAYINDICATEALOSSOFMUSCLE TONEINLEGBLOODVESSELSANDLESSRESISTANCETOEXPANSIONBYʅUIDS ASWELLASWEAK ENEDABILITYTORESPONDTOSHORT TERMBLOODPRESSURECHANGESINGENERAL;#HARLESETAL = 4HERE IS HOWEVER SIGNIʄCANT INTER AND INTRAINDIVIDUAL DIFFERENCES IN THE RESPONSESTOIN ʅIGHT,".0TESTS WHICHMAKEITDIFʄCULTTOUSETHISTESTFORPREDICTING WHICHASTRONAUTSWILLBEMORESUSCEPTIBLETOORTHOSTATICINTOLERANCEAFTERLANDING &URTHER IN ʅIGHT ORTHOSTATIC COUNTERMEASURES AND EXERCISE EQUIPMENT CAN ALSO INCLUDE WHOLE BODY ELASTIC LOADING SUITS SUCH AS THE 2USSIAN ȃ0ENGUINȄ SUIT &IGURE PHARMACOLOGICALPREPARATIONS ANDELECTRO MYOSTIMULATION  -EDICATION /RTHOSTATICINTOLERANCEISCLINICALLYTREATEDUSINGDRUGSTHATACTBYDECREASINGPERIPH ERAL VENOUS CAPACITY PREVENTING BLOOD POOLING INCREASING VASOCONSTRICTION AND INCREASING TOTAL PERIPHERAL RESISTANCE -IDODRINE A SELECTIVE ALPHA  ADRENERGIC



&UNDAMENTALSOF3PACE-EDICINE

Figure 4.22. Left: The Inside of the “Penguin” Suit Contains a System of Elastic, Straps, and Buckles That Can Be Used to Adjust the Fit and Tension of the Suit. This Suit Forces the Subjects to Use His Extensor Muscles In-Flight to Activate Venous Return. (Credit Philippe Tauzin). Right: CSA Astronaut Robert Thirsk Exercising with Bungee Cords While Wearing the “Penguin” Suit. (Credit NASA).

A GONIST HAS BEEN EXTENSIVELY USED ON %ARTH TO TREAT LOW BLOOD PRESSURE 4HIS DRUG PRODUCESARTERIALANDVENOUSCONSTRICTIONRESULTINGINANINCREASEINBLOODPRESSUREBY BARORECEPTORREʅEXES#LINICALTRIALSHAVESHOWNTHATMIDODRINEISEFFECTIVEINTREATING ORTHOSTATIC HYPOTENSION SECONDARY TO AUTONOMIC FAILURE 4HE ABILITY OF THIS DRUG TO VASOCONSTRICTWITHOUTINCREASINGHEARTRATEMAKESITAUSEFULADJUNCTIVETREATMENTTO THEMEASURESCURRENTLYBEINGUSEDFORPOSTʅIGHTORTHOSTATICHYPOTENSION7HENADMIN ISTEREDTOCREWMEMBERSWITHINǻHAFTERLANDING MIDRODINEHASPROVENTOBEAVERY SAFEANDEFFECTIVETHERAPYFORORTHOSTATICHYPOTENSION-IDRODINEDOESNOTPASSTHE BLOOD BRAIN BARRIER WHEN TAKE ORALLY 4HEREFORE THIS DRUG HAS NO CENTRAL STIMULANT EFFECTS4HEEFFECTSOFMIDODRINEAREPARTICULARLYPROTECTIVEOFORTHOSTATICTOLERANCEIN ASTRONAUTS WHO BECOME PRESYNCOPAL ON LANDING DAY DUE TO INADEQUATE RELEASE OF NOREPINEPHRINE;&RITSCH 9ELLEETAL =  -ONITORING 4HE )33 (UMAN 2ESEARCH &ACILITY (2& IS OUTʄTTED WITH EQUIPMENT NECESSARY TO MAKEAVARIETYOFMEASUREMENTSOFTHECARDIO VASCULARFUNCTION-OSTOFTHESEMEA SUREMENTSCANBEMADEINCONJUNCTIONWITHEXERCISEEQUIPMENTUSE4HECAPABILITIES AVAILABLEFORON ORBITRESEARCHARESUMMARIZEDIN4ABLE

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE Table 4.3.



List of Equipment Available on the ISS for Cardio-Vascular Research.

Blood Pressure Capabilities include noninvasive monitoring and collection of blood pressure data, both extended duration and intermittent, on human subjects. The data can be collected by manual or automated methods during periods of rest or exercise Electrical Stimulation of Muscle Local noninvasive muscle stimulation on human subjects using a high current stimulator that provides trains of pulses up to 0.8 amps, according to pre-programmed protocols ECG/EMG/EEG Acquisition of human physiological data such as ECG, EMG, EEG, temperature, and skin galvanic responses. Multichannel data (16 differential channels) can be collected by means of portable, crew-worn devices over extended periods of time (24 h), or via rack-mounted devices Pulse/Blood Oxygen A pulse oximeter to monitor the percentage of hemoglobin oxygen saturation in the blood Lung Volume Respiration of crewmembers can be studied by continuously monitoring lung volume using respiratory impedance plethysmography Metabolic Activity/Pulmonary Physiology s 4WOGASANALYZERSAREAVAILABLE ONEBASEDONTHEUSEOFMASSSPECTROMETRYANDTHE other on infrared gas analysis techniques s #OMBINEDWITHANCILLARYEQUIPMENT INCLUDINGGASSUPPLIESFORSUPPLYINGSPECIAL respiratory gas mixtures s 4HEFOLLOWINGMEASUREMENTSAREPOSSIBLEBREATH BY BREATHMEASUREMENTSOF6/2, VCO2; diffusing capacity of the lung for CO2; expiratory reserve volume; forced expired spirometry; functional residual capacity; respiratory exchange ratio; residual volume; total lung capacity; tidal volume; alveolar ventilation; vital capacity; volume of pulmonary capillary blood; dead-space ventilation; cardiac output



%NDOFMISSION

)TISWELLKNOWNTHATDRINKINGABOUT,OFABALANCEDSALTSOLUTIONLEADSTOANINCREASED BLOOD PLASMA VOLUME LOADS BY ABOUT  M, FOR AT LEAST  H %ARLY SPACE SHUTTLE SPACEMISSIONSVERIʄEDTHATTHISTECHNIQUEOFTEMPORARILYINCREASINGPLASMAVOLUME COULDBEUSEDBYASTRONAUTSTOEASETHEORTHOSTATICINTOLERANCEONLANDING4HEʅUID LOADINGPROTOCOLCONSISTSININGESTINGABOUT,OFWATERORJUICEANDEIGHTSALTTABLETS ABOUTHBEFORELEAVINGORBIT&IGURE 4HISPRODUCES,OFISOTONICSALINESOLU TIONINTHEDIGESTIVETRACK WHICHTHENLEADSTOABSORPTIONANDSUBSEQUENTINCREASEIN PLASMA VOLUME 4HIS TECHNIQUE PROVED EFFECTIVE FOR SHORT DURATION MISSION &OR EXAMPLE FORASTRONAUTS THOSEWHOHADPRACTICEDȃʅUIDLOADINGȄHADLOWERHEART RATES MAINTAINEDBLOODPRESSUREBETTER ANDREPORTEDNOFAINTNESSCOMPAREDTO ASTRONAUTSHAVINGFAINTNESSINACONTROLGROUP (OWEVER THEEFFECTIVENESSOFʅUID



&UNDAMENTALSOF3PACE-EDICINE

LOADINGISREDUCEDWITHLONGERTIMEINORBIT-AYBEFACTORSOTHERTHANCARDIO VASCULAR DECONDITIONINGBECOMEMOREIMPORTANTONLONGERʅIGHTSWITHREGARDTOCAUSINGORTHO STATICINTOLERANCE;"UCKEYETAL A= )N THE CRITICAL PERIOD OF RE ENTRY AND LANDING ASTRONAUTS MAY ROUTINELY WEAR ANTI GRAVITY SUITS 4HESE SUITS CONTAIN BALLOON LIKE PRESSURE BLADDERS IN THE PANTS WHICHCANBEINʅATEDWITHAIRBYTHEASTRONAUT7HENTHEASTRONAUTINʅATESTHEBLAD DERSINHISPANTS THEBLADDERPRESSESAGAINSTHISORHERLEGS FORCINGBODYʅUIDINTOTHE UPPERBODY4HISHELPSTHEHEARTPUMPTHEBLOODMOREEFʄCIENTLYBYPUSHINGTHEBLOOD OUTOFTHELOWEREXTREMITIES4HE2USSIANSWRAPTHELOWERBODYTIGHTLYWITHELASTIC STRAPPING+ARKAS TOACHIEVETHESAMEEFFECTASTHEANTI GRAVITYSUIT !NYONEWHOHASBEENONORBITFORMORETHANDAYSISREQUIREDTOBERETURNEDTO %ARTHINTHESUPINEPOSITION'XACCELERATION TOREDUCETHERISKOFORTHOSTATICINTOL ERANCE DURING RE ENTRY AND LANDING 4HE SPACE SHUTTLE IS EQUIPPED WITH RECUMBENT SEATSFORRETURNINGLONG DURATIONCREWMEMBERSFROMTHE)334HE3OYUZISEQUIPPED WITHCOUCHESTHATARECUSTOM ʄTTOEACHASTRONAUTANDCOSMONAUTPRIORTOTHEIRʅIGHT SEE &IGURE   4HE NOMINAL RE ENTRY ACCELERATION LEVELS ARE ǻG (OWEVER THE 3OYUZCOUCHESAREDESIGNEDISTOENDUREBALLISTICLOADSONTHEORDEROFǻG!TLEAST SIX OF THE APPROXIMATELY  HUMAN 3OYUZ MISSIONS SINCE  HAVE EXPERIENCED HIGH GBALLISTICRE ENTRIES INCLUDINGTHREEFROMTHE)334HE3OYUZLANDINGROCKETS HAVEATTIMESʄREDPREMATURELYWHENTHESYSTEMWASARMEDATHEATSHIELDJETTISON RESULTINGINAȃHARDER THAN NORMALȄLANDING3O THEREISACONCERNTHATSOMELONG DURATIONʅIGHTCREWMEMBERSCOULDPROBABLYNOTEGRESSFROMTHE3OYUZCOUCHESWITH OUTASSISTANCE ESPECIALLYAFTERBALLISTICRE ENTRY %MERGENCYPROCEDURESWEREIMPLEMENTEDFOURTIMESBYTHE2USSIAN3PACE!GENCY DURING-IRMISSIONS4HEPROCEDURESWEREUSEDTWICEFORMEDICALEVACUATIONS ONCE FORCONTAMINATEDATMOSPHERE ANDONCEFORADAMAGEDSPACESTATIONWINDOW.!3! ʅIGHT SURGEONS PERFORMED AN EVALUATION OF THE 3OYUZ 4- SPACECRAFT ALONG WITH ITS LAUNCHANDRE ENTRYCOUCHFORTHEMEDICALTRANSPORTROLEIN*UNEOF"ECAUSEOF THE 3OYUZ HATCH AND COUCH CONSTRAINTS ESSENTIALLY NO MEDICAL RESTRAINT SYSTEM WAS POSSIBLESOTHATEACHPATIENTHADTOȃBENDINȄ!NILLORINJUREDCREWMEMBERWOULD NEED TO BE SECURED IN THE CENTER COUCH FOR REACH AND VISION 4HE STUDY SUMMARY CONCLUDED THAT 3OYUZ APPEARS FEASIBLE FOR A MEDICALLY CRITICAL BUT STABLE PATIENT ;:AK = 0ARTICIPANTSINCOMMERCIALSUBORBITALʅIGHTSCANEXPECTGFORCESRANGINGFROMTO GDURINGASCENT ANDUPTOGALONGTHEBODYȀSLONGITUDINALAXISDURINGRE ENTRY &IGURE 3OMECOMPANIESARETOUTINGANȃAERODYNAMICDESIGNFORACAREFREEAND HEATFREERE ENTRYFOLLOWEDBYAGLIDERUNWAYLANDINGȄ WHILEOTHERSCLAIMTOȃFEATURE 3OYUZ LIKECUSTOM ʄTSEATSFORENDURINGLAUNCHANDRETURNG FORCESȄ4HECUSTOMSEATS MAYBEKEPTASASOUVENIROFTHEMEMORABLEʅIGHT0ASSENGERSWHOSUFFERFROMHIGH BLOOD PRESSURE HAVE HAD A PREVIOUS HEART ATTACK USE AN IMPLANTED PACEMAKER OR DEʄBRILLATOR ANDOTHERSWITHPROVENHEARTDISEASESUCHASCARDIOMYOPATHYWILLBEAT SIGNIʄCANTRISKASARESULTOFTHESEHIGHGLOADS ! PERSON WITH AN UNKNOWN UNDOCUMENTED PRE EXISTING HEART ANOMALY IS THE GREATEST CONCERN FOR COMMERCIAL SPACEʅIGHT ENTERPRISES 4HE SPACEʅIGHT EVENT COULDTHENPROVEDEADLY4HEHIGHACCELERATIONSALSOPUTPARTICIPANTSWITHANEURYSMS INANINCREASEDRISKSITUATION4HEANEURYSMMAYRUPTUREASARESULTOFTOTHEHIGH

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



Figure 4.23. Interiors of the Rocket-Powered Space Planes that Would Take Space Tourists in Suborbital Flight. The Cabin Would Feature Hammock-Like Seats That, According to the Astrium Designer, “Balance Themselves to Minimize the Effects of Acceleration and Deceleration. (Credit Virgin Galactic (left) and Astrium (right)).

ACCELERATIONS BECAUSE OF THE PATHOLOGICALLY WEAK ARTERIAL WALL FAILING &OR MANY COMMERCIALSPACEʅIGHTPASSENGERS THEACCELERATIONSCOUPLEDTOTHEEMOTIONALSTRESS OF THE SUBORBITAL ʅIGHT ARE LIKELY TO CAUSE A DRAMATIC INCREASE IN HEART RATE BLOOD PRESSURE BODYTEMPERATURE ANDMUSCLETENSION4HEAFTEREFFECTSOFTHEȃADRENALINE RUSHȄCANALSOLEADTOSYNCOPEORFAINTINGDUETOASUDDENDROPINBLOODPRESSURE DURINGTHERECOVERYPHASE ASWELLASORTHOSTATICINTOLERANCEANDSINUSARRHYTHMIA)T IS HIGHLY RECOMMENDED THAT THE BIOMEDICAL PARAMETERS OF COMMERCIAL SPACEʅIGHT PARTICIPANTRESPONSESTOSUBORBITALʅIGHTBEMONITOREDDURINGALLPHASESOFTHEʅIGHT ;-C$ONALDETAL = )NCONCLUSION DESPITETHEUSEOFIN ʅIGHTCOUNTERMEASURES ORTHOSTATICINTOLERANCE REMAINSAMAJOR UNRESOLVED CLINICALANDOPERATIONALPROBLEM;#HURCHILLAND"UNGO =2ESEARCHONTHEEFFECTSOFSPACEʅIGHTONTHECARDIO VASCULARSYSTEMCURRENTLY INCLUDES THREE TYPES OF APPROACH A MECHANISTIC STUDIES STRUCTURED TO CONTROL FOR MANY PARAMETERS AND DEVELOP A GENERIC MODEL B DESCRIPTIVE STUDIES OF CARDIO VASCULARANOMALIESTHATMAYHAVEOPERATIONALIMPLICATIONS ASWELLASPROSPECTIVEAND RETROSPECTIVESTUDIESONALARGENUMBEROFASTRONAUTSTHATCOULDINDICATETHERISKOR INCIDENCE OF AN OBSERVED CARDIO VASCULAR ANOMALY CAUSED BY SPACE TRAVEL AND C STUDIESONTHEVALIDATIONSOFCOUNTERMEASURESTHATARECONDUCTEDAFTERTHEMECHA NISMSRESPONSIBLEFORCARDIO VASCULARDECONDITIONINGORPATHOLOGYAREWELLUNDERSTOOD .EVERTHELESS THEPROBLEMOFLONG DURATIONEXPOSURETOMICROGRAVITYLOOMSLARGE CURRENTLYOBSERVEDSPACEEFFECTSMAYINTENSIFYORNEWONESMAYAPPEAR!TPRESENT ALLCARDIO VASCULARCHANGESAREENTIRELYREVERSIBLEUPONRETURNTONORMALGRAVITY AND THEREAPPEARSTOBENODELETERIOUSEFFECTOFSPACEʅIGHTDIRECTLYUPONTHEHEART-IGHT ORTHOSTATICINTOLERANCEBECOMEIRREVERSIBLEAFTERLONG DURATIONEXPOSURE(OWWILL LONGERMISSIONSAFFECTTHETIMECOURSEOFCARDIO VASCULARRE ADAPTATIONTO%ARTHOR -ARSGRAVITY7ILLLONG DURATIONSPACEʅIGHTBRINGIRREVERSIBLEMYOCARDIALDEGEN ERATION OR ȃHYPOTROPHYȄ 4HESE ARE JUST SOME OF THE QUESTIONS THAT REMAIN TO BE ADDRESSED



&UNDAMENTALSOF3PACE-EDICINE

2EFERENCES "ARRATT- 0OOL3EDS  0RINCIPLESOF#LINICAL-EDICINEFOR3PACE&LIGHT.EW 9ORK .93PRINGER "UCKEY*# ,ANE,$*R ,EVINE"$ 7ATENPAUGH$% 7RIGHT3* -OORE7% 'AFFNEY &! "LOMQVIST#'A /RTHOSTATICINTOLERANCEAFTERSPACEʅIGHT*OURNALOF !PPLIED0HYSIOLOGYǻ "UCKEY*# 'AFFNEY&! ,ANE,$*R ,EVINE"$ 7ATENPAUGH$% 7RIGHT3* 9ANCY #- *R -EYER $- "LOMQVIST #' B #ENTRAL VENOUS PRESSURE IN SPACE *OURNALOF!PPLIED0HYSIOLOGYǻ #HARLES *" "UNGO -7 &ORTNER '7  #ARDIOPULMONARY FUNCTION )N 3PACE 0HYSIOLOGY AND -EDICINE .ICOGOSSIAN !% (UNTOON #, 0OOL 3, EDS 0HILADELPHIA 0!,EA&EBIGER #HAPTER #HURCHILL 3%  2ESPONSE OF CARDIOVASCULAR SYSTEM TO SPACEʅIGHT )N +EYS TO 3PACE (OUSTON ! 2YCROFT - EDS "OSTON -! -C'RAW (ILL #HAPTER  PPǻ #HURCHILL3% "UNGO-7 2ESPONSEOFTHECARDIOVASCULARSYSTEMTOSPACE ʅIGHT)N&UNDAMENTALSOF3PACE,IFE3CIENCES#HURCHILL3%ED -ALABAR&, +RIEGER0UBLISHING#OMPANY 6OLUME) #HAPTER %CKBERG$, &RITSCH*- )NʅUENCEOF DAYHEAD DOWNBEDRESTONHUMANCAROTID BARORECEPTOR CARDIACREʅEXFUNCTION!CTA0HYSIOOGICA3CANDINAVIAǻ %LERT' &RAMESOF2EFERENCE4HE0HYSICS(YPERTEXTBOOK;ONLINE=!VAILABLE HTTPHYPERTEXTBOOKCOMPHYSICSMECHANICS;!CCESSED/CTOBER= %NGLISH+% ,OEHR*! ,AUGHLIN-! ETAL 2ELIABILITYOFSTRENGTHTESTINGUSING THEADVANCEDRESISTIVEEXERCISEDEVICEANDFREEWEIGHTS7ASHINGTON $#.ATIONAL !ERONAUTICSAND3PACE!DMINISTRATION .!3!4ECHNICAL0APER .!340   &OLDAGER. !NDERSEN4! *ESSEN&" %LLEGAARD0 3TADEAGER# 6IDEBAEK2 .ORSK0  #ENTRAL VENOUS PRESSURE IN HUMANS DURING MICROGRAVITY *OURNAL OF !PPLIED0HYSIOLOGYǻ &RITSCH 9ELLE*- #HARLES*" *ONES-- "EIGHTOL,! %CKBERG$, 3PACEʅIGHT ALTERS AUTONOMIC REGULATION OF ARTERIAL PRESSURE IN HUMANS *OURNAL OF !PPLIED 0HYSIOLOGYǻ &RITSCH 9ELLE*- 7HITSON0! "ONDAR2,  3UBNORMALNOREPINEPHRINERELEASE RELATESTOPRESYNCOPEINASTRONAUTSAFTERSPACEʅIGHT*OURNALOF!PPLIED0HYSIOLOGY ǻ &RITSCH 9ELLE*- ,EUENBERGER5! $Ȁ!UNNO$3 ETAL !NEPISODEOFVEN TRICULAR TACHYCARDIA DURING LONG DURATION SPACEʅIGHT !MERICAN *OURNAL OF #ARDIOLOGYǻ 'ERNHARDT -, *ONES *! 3CHEURING 2! ET AL  2ISK OF COMPROMISED %6! PERFORMANCEANDCREWHEALTHDUETOINADEQUATE%6!SUITSYSTEMS)N.!3!ȀS (UMAN 2ESEARCH 0ROGRAM %VIDENCE "OOK #HAPTER  !VAILABLE AT HTTP HUMANRESEARCHJSCNASAGOVELEMENTSSMOHRP?EVIDENCE?BOOKASP;!CCESSED /CTOBER= 'HARIB # #USTAUD -!  /RTHOSTATIC TOLERANCE AFTER SPACEʅIGHT OR SIMULATED WEIGHTLESSNESSBYHEAD DOWNBED REST"ULLETIN!CADEMY.ATIONALOF-EDICINE ǻ

4HE#ARDIO 6ASCULAR3YSTEMIN3PACE



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#HAPTER 4HE-USCULO 3KELETAL3YSTEMIN3PACE

-USCLEANDBONEFORMASARESULTOFLIFEINA GENVIRONMENTANDTHEMECHANICAL FORCESEXERTEDONTHEBODY)NMICROGRAVITY SUPPORTMUSCLESSUCHASTHOSEINTHECALF ANDTHIGHDECLINEINVOLUME STRENGTH ANDMASS3IMILARLY BONESLOSECALCIUM THE MINERALFROMWHICHTHEYDERIVETHEIRSTRUCTUREANDSTRENGTH THROUGHTHEPROCESSOF DEMINERALIZATION )S THE REPORTED LOSS OF MUSCLE AND BONE MASS THAT OCCURS DURING SPACEʅIGHTSELF LIMITINGORDOESITCONTINUE)SITPERMANENTORISITREVERSIBLE#OULD THEPARALLELLOSSOFMUSCULARSTRENGTHANDCOORDINATIONJEOPARDIZETHERETURNOFPILOTED SPACECRAFTORLIMITWORKCAPABILITYANDPERFORMANCEFORSURFACEOPERATIONSON-ARS 4HIS CHAPTER EXAMINES THE EFFECTS OF SPACEʅIGHT ON STRUCTURE AND FUNCTION OF THE MUSCULO SKELETALSYSTEM WHATTHEIMPLICATIONSOFSUCHCHANGESMIGHTBEFORLONG DURATION EXPLORATORY MISSIONS AND WHAT COUNTERMEASURES MIGHT BE EMPLOYED TO PREVENTUNDESIRABLECHANGES&IGURE 

 4HEPROBLEMMUSCLEATROPHYANDBONELOSS  -USCLEATROPHY !FTERAFEWDAYSOFEXPOSURETOMICROGRAVITY MUSCLEATROPHYBEGINSANDTHEURINARY EXCRETIONOFNITROGENCOMPOUNDSINCREASES4HISATROPHYISCHARACTERIZEDBYSTRUC TURALANDFUNCTIONALALTERATIONSINTHEMUSCLETISSUE4HEREISADECREASEINMUSCLEʄBER SIZE WITH NO APPARENT CHANGE IN ʄBER NUMBER !TROPHY IS CONSIDERABLY GREATER FOR POSTURALMUSCLES IE THOSEMUSCLESTHATSUPPORTACTIVITIESSUCHASWALKING LIFTING OBJECTS AND STANDING ON %ARTH AS COMPARED TO THE NON POSTURAL MUSCLES WHICH UNDERGO ONLY MARGINAL CHANGES !STRONAUTS LOSE ǻ OF THEIR MUSCLE MASS ON SHORTMISSIONS/NLONG DURATIONʅIGHTS THEMUSCLEMASSLOSSMIGHTRISETOINTHE ABSENCEOFCOUNTERMEASURES4HEVISIBLEREDUCTIONINTHELEGCIRCUMFERENCEHASBEEN USEDASANINDICATOROFMUSCLEATROPHY&IGURE (OWEVER ASSEENINTHEPRECEDING CHAPTERSEE#HAPTER 3ECTION THISREDUCTIONISALSOINʅUENCEDBYTHESHIFTOF ʅUIDSFROMTHELOWERTOTHEUPPERBODYINMICROGRAVITY 4HEMUSCLELOSSISPRESUMABLYCAUSEDBYCHANGESINTHEMUSCLEMETABOLISM IE THEPROCESSOFBUILDINGANDBREAKINGDOWNMUSCLEPROTEINS%XPERIMENTSPERFORMED DURINGLONG DURATIONMISSIONSONBOARD-IRHAVEREVEALEDADECREASEOFABOUTIN THERATEOFPROTEINSYNTHESISINHUMANS;$I0RAMPEROETAL = )NADDITIONTOPUREMUSCLELOSS THEʄBERSINVOLVEDINMUSCLECONTRACTIONSCHANGE THEIRCONTRACTILEPROPERTIESANDAREWEAKENED3IGNIʄCANTDECREASESINSTRENGTHOFTHE TRUNK KNEEANDSHOULDERMUSCLESHAVEBEENFOUNDINASFEWASDAYSINMICROGRAVITY G. Clément, Fundamentals of Space Medicine, Space Technology Library 23, DOI 10.1007/978-1-4419-9905-4_5, © Springer Science+Business Media, LLC 2011



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Figure 5.1. Muscle Atrophy and Bone Demineralization Are Serious Concerns for LongDuration Spaceflights. (Credit NASA).

%XTENSORMUSCLESAREMOREAFFECTEDTHANʅEXORMUSCLES!NIMALSTUDIESALSOREVEALED THATMUSCLEʄBERREGENERATIONISLESSSUCCESSFULINSPACE4HEASSOCIATEDCONTINUED EXCRETIONOFNITROGENMAYALSOHAVEDELETERIOUSHORMONALANDNUTRITIONALEFFECTS 3PACEʅIGHTALSORESULTSININCREASEDSUSCEPTIBILITYOFSKELETALMUSCLETOCONTRACTION DAMAGE WHICHOCCURSINMUSCULARATROPHIESON%ARTH BOUNDPATIENTS4HESEEFFECTS MAYCOMPROMISETHEABILITYOFASTRONAUTSTOPERFORMSOMEOFTHEIRACTIVITIESINORBIT ,IKEWISE THEYMAYNOTBEABLETOWITHSTANDTHESTRESSOF GUPONRETURNTO%ARTH )NFACT THEMUSCLEWEAKNESS FATIGUE FAULTYCOORDINATION ANDDELAYED ONSETMUSCLE SORENESSTHATASTRONAUTSEXPERIENCEAFTERSPACEʅIGHTMIMICSTHECHANGESSEENINBED RESTPATIENTSANDTHEELDERLY&INALLY ITISIMPORTANTTOBEARINMINDTHATMUSCLEATRO PHYCAUSEDBYWEIGHTLESSNESSALSOPARTICIPATESINTHEPOSTURALINSTABILITYANDLOCOMO TIONDIFʄCULTIESSEENAFTERSPACEʅIGHTSEE#HAPTER 3ECTION  

"ONELOSS

"ONELOSSDURINGSPACEʅIGHTISABOUTǻPERMONTH4HEEFFECTISESPECIALLYMARKED IN THE WEIGHT BEARING BONES OF THE LEGS AND SPINE &IGURE   #ERTAIN INDIVIDUALS SPENDINGMONTHSINORBITHAVELOSTASMUCHASOFBONEMASSTHROUGHOUTTHEIR LOWEREXTREMITIES4HEREISNOINDICATIONTHATTHISBONELOSSABATESWITHLONGERʅIGHTS )NADDITION AFTERRETURNTO%ARTH BONELOSSCONTINUESFORSEVERALMONTHS

4HE-USCULO 3KELETAL3YSTEMIN3PACE



Figure 5.2. A “Cast” Placed on the Leg of an Astronaut Is Used To Measure Changes in Leg Circumference, as an Indicator of Changes in Muscle Mass During Spaceflight. Several Times Over the Course of the Mission, an Astronaut Will Put on the Cast, Pull the Tapes Tight, and Mark Them. By Comparing the Marks, Changes in Muscle Volume Can Be Measured. (Credit NASA).

"ONELOSSOFTHISMAGNITUDELEADSTOASIGNIʄCANTINCREASEINFRACTURERISK WHICH MAY BE AS MUCH AS ʄVE FOLD OVER THAT EXPECTED WITH NORMAL BONE MASS ON %ARTH "ONESCOULDFRACTUREUNDERTHEEXTREMESTRESSOFHEAVYWORKDURINGEXTRA VEHICULAR ACTIVITY FOREXAMPLE OREVENUPONRETURNTOG "ONESLOSECALCIUM THEMINERALFROMWHICHTHEYDERIVETHEIRSTRUCTUREANDSTRENGTH THROUGHTHEPROCESSOFDEMINERALIZATION4HISINCREASEDEXCRETIONOFCALCIUMMAYIN TURNAFFECTVARIOUSORGANS ESPECIALLYTHEKIDNEYS&OREXAMPLE THERISKOFRENALSTONE FORMATIONISINCREASEDANDCOULDHAVESERIOUSCONSEQUENCESDURINGAMISSION)NADDI TIONTODEMINERALIZATION CHANGESINBONEMARROW WHICHISTHESITEOFBLOOD FORMING CELLS HAVEALSOBEENLINKEDTOBONELOSS !NIMAL STUDIES HAVE INDICATED THAT THE STRUCTURE OR ȃARCHITECTUREȄ OF THE BONE FORMEDINSPACEISDIFFERENTFROMTHATOFANIMALSON%ARTH4HUS FORLABORATORYRATS THATHAVEʅOWNINSPACE STRENGTHDOESNOTINCREASEPROPORTIONALLYTOTHEINCREASEIN BONESIZEASITDOESON%ARTH)FTHESAMECHANGESOCCURINHUMANS ITISREASONABLETO ASK WHAT WILL BE THE NEW STATE FOR BONE IN MICROGRAVITY AFTER VERY LONG DURATION MISSIONS4HEMAJORHEALTHHAZARDSASSOCIATEDWITHSKELETALBONELOSSDURINGTHESE



&UNDAMENTALSOF3PACE-EDICINE

Figure 5.3. Changes in Bone Mass Relative to Preflight Level in Cosmonauts During LongDuration Missions on Board Mir. Bone Loss Seems to be a Regional Phenomenon in Which the Bone Areas with the Greatest Decrease in Load, i.e., the Hip, Lose the Most Bone. Interestingly Enough, Bone Mass Increases at the Head Level, Presumably Because of the Increase in Pressure Due To the Headward Fluid Shift in Microgravity [Clément et al., 2010].

MISSIONSAREACCUMULATIONSOFEXCESSMINERALINTISSUESSUCHASTHEKIDNEY INCREASED RISKOFFRACTURE ANDPOTENTIALLYIRREVERSIBLEDAMAGETOTHESKELETON "ONELOSSISACONCERNRIGHTHEREONOUROWNPLANETASWELL-ILLIONSWORLDWIDE SUFFERFROMBONELOSS KNOWNASOSTEOPOROSIS2ESEARCHERSHOPETHATSOLVINGTHEISSUE OFBONELOSSINSPACEWILLREVEALIMPORTANTCLUESABOUTWHATCAUSESOSTEOPOROSISON %ARTH !STRONAUTSREGULARLYPERFORMWEIGHT LOADINGEXERCISESTHATSIMULATETHEGRAVITYOF %ARTH(OWEVER EXERCISEALONEHASNOTPREVENTEDMUSCLEANDBONELOSSDURINGSPACE ʅIGHT$IFFERENTTYPESOFEXERCISEAREREQUIREDTOBUILDMUSCLESTRENGTHANDRESISTANCE TOFATIGUEANDINJURY ASWELLASMAINTAINBONEINTEGRITY3TUDIESAREBEINGCONDUCTED TOADDRESSHOWMUSCLESANDBONESSHOULDBELOADEDINMICROGRAVITYTOPREVENTTHESE CHANGES!BALANCEAMONGHEALTHYNUTRITION THERAPEUTICMEASURES DRUGS ANDEXER CISEISLIKELYTOBETHEMOSTEFFECTIVECOUNTERMEASURE

 -USCLEANDBONEPHYSIOLOGY  -USCLEPHYSIOLOGY 4HEREARESEVERALTYPESOFMUSCLETISSUEINTHEHUMANBODY4HEMUSCLESTHATARETHE MOSTAFFECTEDBYSPACEʅIGHTARETHESKELETALMUSCLES WHICHARETHOSEDIRECTLYATTACHED TOTHESKELETON3KELETALMUSCLESARETHELARGESTTISSUESINTHEBODY ACCOUNTINGFOR

4HE-USCULO 3KELETAL3YSTEMIN3PACE



ǻOFTHETOTALBODYWEIGHT4HESEMUSCLESAREATTACHEDTOTHEBONESBYTENDONS 4HEIRCONTRACTIONALLOWSFORTHEMOVEMENTOFJOINTSINEVERYDAYACTIVITIES LIKEWALK ING LIFTING OBJECTS AND STANDING 4HE ANTI GRAVITY MUSCLES ALSO KNOWN AS POSTURAL MUSCLES OWETHEIRIMPORTANCEANDSTRENGTHTOTHEPRESENCEOFGRAVITY&IGURE  3KELETALMUSCLECELLS CALLEDʄBERS ARECYLINDRICALCELLS ABOUTPMINDIAMETER %ACHMUSCLEʄBERCONTAINSSEVERALHUNDREDMYOʄBRILS ABOUTPMINDIAMETERASWELL ASMANYMITOCHONDRIAFORADENOSINETRIPHOSPHATE!40 PRODUCTIONANDACOMPLEX SYSTEMOFINTERNALMEMBRANESCALLEDTHESARCOPLASMICRETICULUM WHICHREGULATESCAL CIUMIONLEVELSINTHEʄBER!MYOʄBRILCONSISTSOFMANYʄLAMENTSOFMYOSINAND ACTIN THESTRUCTURALUNITOFCONTRACTION&IGURE  !40ISTHEBASICSOURCEOFCHEMICALENERGYFORMUSCLECONTRACTION(OWEVER THE AMOUNTOF!40PRESENTINTHEMUSCLECELLSISONLYSUFʄCIENTTOSUSTAINMAXIMALMUSCLE POWERFORǻS#ONSEQUENTLY NEW!40MUSTBEFORMEDCONTINUOUSLY4HREEPRO CESSESCANBEUSEDA THEPHOSPHAGENSYSTEMCANSUSTAINǻMORESOFMUSCLE ACTIVITYB THEGLYCOGEN LACTICACIDSYSTEMANAEROBICSTEPOFGLUCOSEBREAKDOWN ALLOWSANOTHERǻSȃBURSTSȄOFENERGYANDC THEAEROBICSYSTEMPROVIDESMUSCLE ACTIVITYTHATISONLYLIMITEDBYTHEOXYGENANDNUTRIENTSSUPPLIES %ACHMUSCLEʄBERISSUPPLIEDBYAMOTORNERVEAXON ANDCONTRACTSWHENTHAT AXONȃʄRESȄANACTIONPOTENTIAL-USCLEACTIONPOTENTIALSAREFASTǻMSINDURATION ANDAREALL OR NOTHING IE NOTGRADED7HENASINGLESTIMULUSISAPPLIEDTOTHEMUSCLE ʄBER ITRESPONDSBYATWITCH4HETWITCHFORCEISAWEAKFORCEANDISVERYSLOWCOM PAREDTOTHEDURATIONOFTHEACTIONPOTENTIAL4HEREISALATENTPERIODBETWEENTHESTART OFTHEACTIONPOTENTIALANDTHETIMEWHENTHEʄBERBEGINSTODEVELOPCONTRACTILEFORCE

Figure 5.4. Major Skeletal Muscles in the Body. The Postural Muscles (in Black) Are Used to Counteract the Acceleration of Gravity During Standing on Earth. (Adapted from Lujan and White [1994]. Credit Philippe Tauzin).



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Figure 5.5. Muscles Are Composed of Fibers, Made Up of Smaller Units, the Myofibrils, Which Contain Filaments That Slide for Contraction. (Source Unknown).

DURINGWHICHTHEMUSCLEʄBERCANNOTBESTIMULATEDAGAIN4HEDURATIONOFTHETWITCH FORANYONEMUSCLEʄBERISCONSTANTBUTITCANBESHORTEREG MSINLARGE FAST ʄBERS ORLONGEREG MSINSMALL SLOWʄBERS 4HELATENTPERIODISABOUTTHESAME FORBOTHSLOWANDFASTTYPESOFMUSCLEʄBERS 3LOWOXIDATIVE ʄBERS ALSOCALLED4YPE) ARECHARACTERIZEDBYARELATIVELYSLOW DEVELOPMENT OF FORCE BUT ARE ABLE TO MAINTAIN THIS FORCE RELATIVELY LONG -ARATHON RUNNERSTYPICALLYDEVELOPTHOSEINTHE3OLEUSMUSCLEINTHECALFFORPROLONGEDLOWER LEGMUSCLEACTIVITY&ASTGLYCOLYTIC ʄBERS ALSOCALLED4YPE)) AREABLETODEVELOP FORCEFASTER3PRINTERSANDWEIGHTLIFTERSTYPICALLYDEVELOPTHOSEINTHE'ASTOCNEMIUS MUSCLEINTHECALFANDINTHEBICEPSMUSCLEFORQUICK POWERFULȃBURSTSȄOFMOVEMENT 4HEDOWNSIDEOFFASTʄBERSISTHATTHEYFATIGUERAPIDLY #ONTRACTIONREFERSTOTHEACTIVEPROCESSOFGENERATINGAFORCEINAMUSCLE4HEFORCE EXERTEDBYACONTRACTINGMUSCLEONANOBJECTISTHEMUSCLETENSION&IGURE 4HE FORCEEXERTEDONAMUSCLEBYTHEWEIGHTOFANOBJECTISTHELOAD7HENAMUSCLESHORT ENSANDLIFTSALOAD THEMUSCLECONTRACTIONISISOTONICCONSTANTTENSION 7HENSHORT ENINGISPREVENTEDBYALOADTHATISGREATERTHANMUSCLETENSION THEMUSCLECONTRACTION ISISOMETRICCONSTANTLENGTH  !NOTHERCLASSIʄCATIONOFMUSCLECONTRACTIONISINTOCONCENTRICORECCENTRICCONTRAC TIONS#ONCENTRICCONTRACTIONMEANSTHATTHEMUSCLEʄBERSDECREASEINLENGTH5NDER THEINʅUENCEOFEXTERNALFORCES MUSCLEʄBERSCANINCREASEINLENGTHWHILECONTRACTING 4HIS IS CALLED AN ECCENTRIC CONTRACTION !N EXAMPLE OF AN ECCENTRIC CONTRACTION IS WALKINGDOWNSTAIRS WHENTHEFORCEOFGRAVITYCAUSESTHEMUSCLETOLENGTHENWHILE CONTRACTING$URINGECCENTRICCONTRACTION THEFORCETHATISPRODUCEDBYTHEMUSCLEIS EVENGREATERTHANDURINGISOMETRICCONTRACTION4HISGREATERPRODUCTIONOFFORCEISSTILL

4HE-USCULO 3KELETAL3YSTEMIN3PACE



Figure 5.6. Isotonic Contraction (Left) Is Associated with Constant Tension, Whereas Isometric Contraction (Right) Is Associated with Constant Fiber Length. (Adapted from Lujan and White [1994]. Credit Philippe Tauzin).

UNEXPLAINED BUTISSURPRISINGLYATTHECOSTOFHARDLYANY!407HENGRAVITYISABSENT ECCENTRICCONTRACTIONSRARELYOCCUR WHICHHASBEENSUGGESTEDTOBEANIMPORTANTREA SONWHYMUSCLESATROPHYINMICROGRAVITY;#ONVERTINO = $URINGMUSCLECONTRACTION THEREISASTRICTRELATIONSHIPBETWEENFORCEANDLENGTH "ECAUSEOFTHISRELATIONSHIPITISIMPORTANTTOSTANDARDIZETHEANGLESOFTHERELEVANT JOINTS IE STANDARDIZATION OF THE LENGTH OF THE MUSCLE WHEN COMPARING MUSCLE STRENGTHPRODUCTIONBEFOREANDAFTERACERTAINPERIODOFTIME)NADDITION THEHIGHEST FORCES ARE DEVELOPED AT SLOWER VELOCITIES OF CONTRACTION #ONSEQUENTLY IT IS ALSO IMPORTANT TO COMPARE MUSCLE STRENGTH PRODUCTION AT IDENTICAL ANGULAR VELOCITIES IE STANDARDIZATIONOFTHEVELOCITYOFCONTRACTION  4HE POWER A MUSCLE CAN GENERATE IS LARGELY DEPENDENT ON THE AMOUNT OF ACTIN MYOSINʄLAMENTSTHATCANBEUSED-OREʄLAMENTSMEANMOREPOTENTIALTOGENERATE MUSCULARPULL4HELENGTHANDSIZEOFAMUSCLEʄBERCANVARYCONSIDERABLYBETWEEN VARIOUSMUSCLESINTHEBODYANDBETWEENINDIVIDUALSOFDIFFERENTGENDER ʄTNESS AND AGE4HELENGTHOFAMUSCLEʄBERCANVARYBETWEENSEVERALMILLIMETERSANDAPPROXI MATELYCM ANDISMAINLYRESPONSIBLEFORTHEMAXIMUMVELOCITYOFCONTRACTION 4HESTRENGTHOFAMUSCLEISMAINLYDETERMINEDBYTHESIZEOFMYOʄLAMENTS WHICHIS OFTENINDICATEDBYTHESURFACEAREAOFAPERPENDICULARSLICEOFTHEMUSCLE THECROSS SECTIONALAREA4HEREISGENERALLYAHIGHCORRELATIONBETWEENMAXIMALSTRENGTHANDTHE CROSS SECTIONALAREAOFASPECIʄCMUSCLE ȃ%ATINGALONEWILLNOTKEEPAMANWELL ȄSAID(IPPOCRATESIN"#ȃ(EMUST ALSOTAKEEXERCISEȄ4RAININGINCREASESTHESIZEOFMUSCLEʄBERSANDEVENTHENUMBER OFMUSCLEʄBERS THEREBYINCREASINGTHEMAXIMALSTRENGTHOFAMUSCLE$URINGEXER CISE THECAPACITYOFAMUSCLEFORACTIVITYCANBEALTEREDBYA TRANSFORMATIONOFONE TYPEOFʄBERTOANOTHER EG THEMUSCLESREQUIREDTOPERFORMENDURANCE TYPEACTIVITY WILLDEVELOPMORE4YPE )ʄBERSANDTHEIRNUMBEROFBLOODCAPILLARIESWILLINCREASE

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ORB THEGROWTHINSIZEHYPERTROPHY OFTHEMUSCLESʄBERS EG WEIGHTLIFTINGWILL INDUCEHYPERTROPHYIN4YPE ))ʄBERS WITHANINCREASEINSYNTHESISOFACTINANDMYOSIN ʄLAMENTS 

"ONEPHYSIOLOGY

7ETENDTOTHINKOFBONESASSOMETHINGINERT BUTTHATȀSNOTTHECASE"ONEISALIVING TISSUE"ONETISSUEISCONSTANTLYBEINGBROKENDOWNBYCERTAINCELLS ANDBUILTUPBY OTHER CELLS TO MAINTAIN ITS FUNCTIONAL RIGIDITY -UCH OF THE ACTIVITY FROM THESE SPECIALIZEDCELLSCOMESINRESPONSETOTHESTRESSPUTONTHEBONESDURINGWALKINGOR EXERCISING%VENWHENINBED THEREARESTILLSOMEMUSCULARFORCESACTINGONTHEBONE PROVIDINGTHESTIMULUSFORTHEREMODELINGOFTHEBONE 4HEWEIGHT BEARINGBONESPROVIDEARIGIDSUPPORTFORTHEBODYIN%ARTHȀSGRAVITY &IGURE 4HEPOROUSSTRUCTUREOFTHEBONEISADAPTEDTORESISTTOMECHANICALCON STRAINTSWITHAMINIMUMMASS!NESTIMATEDOFBONESTRENGTHISDETERMINEDBY PUREBONEMASS4HEREMAININGAREDETERMINEDBYTHELABYRINTH LIKESTRUCTUREOF BONE)NADDITION THEBONESACTASAMINERALRESERVOIROFCALCIUM!NADULTCONTAINS APPROXIMATELY GOFCALCIUM OUTOFWHICHSTAYSINTHESKELETONANDONLY INTHEEXTRACELLULARSPACEANDSOFTTISSUES 4HEMAJORCOMPARTMENTSOFALONGBONE SUCHASTHEARMANDLEGBONES INCLUDE A THEPERIOSTEUMOROUTERʄBROUSENVELOPEOFCORTICALBONE WHICHCONTAINSTHEGENES FOR LOCALLY ACTING GROWTH FACTORS B THE COMPACT BONE THE OUTER BONY LAYER VERY

Figure 5.7. Major Bones of the Body with, in Black, Those Primarily Involved in Counteracting the Acceleration of Gravity. (Adapted from Lujan and White [1994]. Credit Philippe Tauzin).

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STRONG AND DENSE WHICH IS THE SITE OF CORTICAL BONE REMODELING AND C THE INNER COMPARTMENT OR MARROW SPACE WHICH CONTAINS BOTH BONE AND BLOOD FORMING CELLS &IGURE 4HECELLULARELEMENTSARECONTAINEDWITHINANINTERCONNECTINGSYSTEMOF SPONGYBONEALSOTERMEDLAMELLARORTRABECULARBONE "ONECONTAINSAMATRIXOFCOLLAGENʄBERS WHICHGIVESTHEBONEACERTAINDEGREEOF ELASTICITY 4HE MATRIX PROVIDES A MEDIUM FOR THE DEPOSITION OF CALCIUM CRYSTALS HYDROXYAPATITE 4HESECRYSTALSPROVIDESTRENGTHTOTHEBONES!LAYEROFCARTILAGE CALLEDTHEGROWTHPLATEISWHERETHEBONEGROWSLONGERBYINCREASINGITSTHICKNESS 4HECARTILAGEISLATERCALCIʄEDWITHHYDROXYAPATITE"ONEISCONTINUALLYBEINGREMOD ELEDUNDERTHEINʅUENCEOFTHREETYPESOFHIGHLYSPECIALIZEDCELLS&IRSTLY OSTEOBLASTS ORBONEFORMINGCELLS SYNTHESIZETHECOLLAGENMATRIXANDCONTROLTHEMINERALIZATION OFTHEBONE3ECONDLY OSTEOCLASTS ORBONERESORPTIONCELLS SECRETEACIDS WHICHDIS SOLVETHEMINERALSANDACTAGAINSTTHEFORMATIONOFBONE COMPONENTS&IGURE  &INALLY OSTEOCYTES PRESERVE THE HOMEOSTASIS OF BONE FORMATION AND RESORPTION /STEOCYTESAREDIFFERENTIATEDOSTEOBLASTS WHICHHAVEBECOMEACTIVETOFORMBONE AND ARECAPABLEOFBOTHSYNTHESISANDRESORPTION/STEOCYTESAREEXTREMELYSENSITIVETO MECHANICALSTRESS "ONEREMODELINGISACONTINUOUSPROCESSTHROUGHOUTLIFEINADULTS ǻOFTHE BONEISREPLACEDEACHYEAR!NASYETUNKNOWNTRIGGERACTIVATESTHEOSTEOCLASTSTOFORM HOLES AND TUNNELS 4HESE HOLES AND TUNNELS ARE ʄLLED WITH A NEW MATRIX BY THE

Figure 5.8. Structure of a Long Bone, Showing the Epiphysis, Which Forms a Joint with Another Bone, the Epiphyseal Plate Where Elongation Is Achieved in the Growth Plate, and the Three Main Compartments of Cortical Bone Within the Diaphysis. A Cross-Section of the Compact Bone Shows the Blood-Forming Cells on the Outer Surfaces, Which Continually Build New Bone to Maintain Its Thickness and Strength. (Adapted from Lujan and White [1994]. Credit Philippe Tauzin).

 !N EASY WAY TO MEMORIZE THE FUNCTION OF OSTEOBLASTS AND OSTEOCLASTS IS THE FOLLOWING OSTEOBLASTS ARE BONE BUILDINGCELLS WHEREASOSTEOCLASTSAREBONE CRUSHINGCELLS



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O STEOBLASTS#ALCIUMCOMPOUNDSMUSTBEPRESENTFOROSSIʄCATIONTOTAKEPLACE4WELVE TOʄFTEENDAYSAFTERTHIS THEMINERALIZATIONOFTHENEWLYFORMEDBONESTARTS#OMPLETE MINERALIZATIONHASTAKENPLACEAFTERǻMONTHS 4HE BALANCE OF THE OSTEOCLAST AND OSTEOBLAST ACTIVITY IS NOT EVEN 5NTIL APPROXI MATELYTHEAGEOF MOREBONEISBEINGFORMEDTHANTHEREISBEINGDISSOLVED WITHAN EXTRASTRONGPOSITIVEBALANCEDURINGPUBERTY4HEREAFTER THEBALANCEBECOMESNEGA TIVEANDTHETOTALAMOUNTOFBONEDECREASES&IGURE 4HEDECREASEISABOUTǻ OFBONEMASSPERDECADE&ORWOMENTHISRATEINCREASESTOǻPERYEARSOMEWHERE BETWEENANDYEARSAFTERMENOPAUSE 7HENHUMANSLOSEBONEDENSITY SOMEOFTHISLOSSCOMESFROMCORTICALBONE BUT THEMAINPARTCOMESFROMTRABECULARBONE4RABECULARBONEISMOSTLYLOCATEDNEXTTO JOINTSATTHEENDSOFTHELONGBONES SUCHASTHEFEMURBALLTHATʄTSINTOTHEHIPSOCKET ANDINVERTEBRALBONES!NYLOSSOFDENSITYATSUCHLOCATIONS WHERETHESKELETONEXPE RIENCESTHEMOSTSTRESS SIGNIʄCANTLYINCREASESTHERISKOFFRACTURES HENCETHELARGER NUMBEROFHIPREPLACEMENTSAMONGELDERLYPEOPLE /STEOPOROSISISABONEDISEASEINWHICHTHEBONEMASSISREDUCEDBYǻPER YEAR)TISASILENTDISEASE WHICHOFTENLEADSTOAFRACTUREWITHOUTANYPRECURSORSYMP TOMS&IGURE )N%UROPE THISDISEASEAFFECTSABOUTOFTHEWOMENAND OFTHEMENOVERYEARSOFAGE ANDCOSTSAPPROXIMATELYBILLION%UROSPERYEAR 7ITHTHEOVERALLAGINGOFPOPULATION OSTEOPOROSISISANINCREASINGPUBLICHEALTHISSUE 4HEMAINRISKFACTORSAREGENETIC HORMONAL ANDRELATEDTOSEDENTARYLIFEWITHLACKOF PHYSICALACTIVITY

Figure 5.9. Under Terrestrial Conditions, a Loss in Bone Mineral Density of 0.5% Per Year Would Be Considered Normal Past the Age of 40, So Bone Loss During Spaceflight Cannot Solely Be Attributed to That Environment. During a Mission to Mars, a 45-Year-Old Astronaut Could See Bone Deterioration Reach the Weakened State of Severe Osteoporosis. (Adapted from National Geographic [2001]).

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Figure 5.10. Scans of Normal (Left) and Osteoporosed (Right) Bone. (Credit MEDES).

 %FFECTSOFSPACEʅIGHTONMUSCLE  $ECREASEINBODYMASS "ECAUSE THE MUSCLES REPRESENT MORE THAN  OF THE BODY MASS CHANGES IN BODY WEIGHTDURINGANDAFTERSPACEʅIGHTISANINDICATOROFMUSCLEATROPHY)NMICROGRAVITY BODYWEIGHTISMEASUREDUSINGASPECIALSCALETHESUBJECTISSEATEDINADEVICEPLACED BETWEEN TWO SPRINGS OF KNOWN CONSTANT 7HEN THE SEAT IS UNLOCKED THE PERIOD OF OSCILLATION IS PROPORTIONAL TO THE SUBJECTȀS MASS 4HE MASS OF THE CREWMEMBERS IS CALCULATEDBYMEASURINGTHEOSCILLATIONPERIODOFTHEIRUNKNOWNMASSANDCOMPARING ITTOTHEPERIODOFAKNOWNMASS&IGURE !SARULE BODYMASSDECREASESBY APPROXIMATELYǻRELATIVETOPREʅIGHTDURINGTHEʄRSTWEEKSOFSPACEʅIGHT0ART OF THIS REDUCTION IS DUE TO THE ʅUID LOSS AS DISCUSSED PREVIOUSLY SEE #HAPTER  3ECTION )NTERESTINGLYENOUGH BODYWEIGHTTENDSTOINCREASEDURINGBEDRESTOR ISOLATION STUDIES &OR EXAMPLE WHEN CONʄNED TO A TERRESTRIAL -IR SIMULATOR FOR  DAYS UNDER CONDITIONS SIMULATING A LONG DURATION SPACEʅIGHT THREE SUBJECTS GAINED BETWEEN  AND  KG 4HIS INCREASE IN WEIGHT IS THOUGHT TO BE DUE TO AN ACCUMULATIONOFSODIUMINEXTRACELLULARSPACE LEADINGTOWATERRETENTIONANDWEIGHT GAIN;4ITZEETAL = 

$ECREASEINMUSCLEVOLUMEANDSTRENGTH

!DECREASEINLEGVOLUME ALSOKNOWNASTHEȃCHICKENLEGSYNDROMEȄ ISALSOOBSERVED INMICROGRAVITY"YTHEENDOFA MONTHMISSION LEGCIRCUMFERENCEMAYDECREASEBY ǻ MOSTLYINTHEʅESHIERTHIGHS0ARTOFTHISDECREASEISDUETOTHEHEADWARD ʅUIDSHIFT(OWEVER ALTHOUGHTHEʅUIDSHIFTISVIRTUALLYCOMPLETEAFTERWEEK LEG VOLUME CONTINUES TO DECREASE THROUGHOUT THE ʅIGHT SUGGESTING THAT MUSCLE LOSS SIGNIʄCANTLY CONTRIBUTES TO THIS DECREASE $URING THE POSTʅIGHT MEASUREMENTS THE LEG VOLUME DOES NOT IMMEDIATELY RETURN TO THE PREʅIGHT LEVEL DESPITE THE QUICK RE HYDRATIONOFTHEORGANISM4HISDIFFERENCEALSOINDICATESTHATLEGVOLUMEISREDUCED INSPACEPARTLYBECAUSEOFMUSCLEATROPHY



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Figure 5.11. Instruments for Measuring the Body Mass of Astronauts and Cosmonauts on Board the ISS. Left: NASA SLAMMD Device. Right: Russian IM System. Both Devices Use a Rigid Frame That Oscillates Whole Human Body, Equivalent to a Spring-Mass System. (Credit NASA).

!NOTHERPOSSIBLEINDICATOROFTHEREDUCTIONINMUSCLEMASSISTHELOSSOFNITROGEN DURINGSPACEʅIGHT.ITROGENISANESSENTIALELEMENTOFEVERYPROTEIN3KELETALMUSCLE ISTHELARGESTACTIVEPROTEINPOOLINTHEBODY THEREBYBEINGTHEMAJORSITEOFPROTEIN LOSS4HUS THEDETERMINATIONOFNITROGENEXCRETIONINURINEISANINDICATOROFMUSCLE TISSUEBREAKDOWN4HEʄNDINGOFINCREASEDEXCRETIONOFTHEPROTEINS METHYLHISTI DINE CREATININE ANDSARCOSINEDURINGSPACEʅIGHT WHICHINDICATESMUSCLEBREAKDOWN CONʄRMEDTHISCONCEPT 3IGNIʄCANT ATROPHY WAS EVIDENT IN HUMAN MUSCLES AFTER ONLY  DAYS IN SPACE &IGURE )THASNOTBEENDETERMINEDWHETHERMUSCLEDETERIORATIONREACHESAPLA TEAUDURINGLONG DURATIONSPACEʅIGHT4HEDEGREEOFATROPHYISDIFFERENTFORVARIOUS MUSCLES;%DGERTONETAL =4HEMUSCLESOFTHEARMSANDSHOULDERSSHOWSMALLER LOSSES THAN THE MUSCLES OF THE LOWER BACK ABDOMEN THIGHS AND LOWER LEGS 4HESE LOWERBODYMUSCLESARECRITICALTOTHEMAINTENANCEOFPOSTUREANDBALANCEON%ARTH ANDSUFFERTHEMOSTFROMTHEDISAPPEARANCEOFGRAVITY4HESMALLERLOSSESINTHEUPPER LIMBMAYALSOBECAUSEDBYANINCREASEDUSEOFTHEARMSDURINGSPACEʅIGHT)NDEED UNDERWEIGHTLESSNESS PREDOMINANTLYTHEARMSAREUSEDTOMOVEWITHINTHESPACECRAFT ANDDURINGEXTRA VEHICULARACTIVITIES 4HE DECREMENTS IN MUSCLE STRENGTH RESEMBLE THE DECREMENTS IN MUSCLE MASS ,ARGERLOSSESINTHEPOSTURALMUSCLESANDLARGERLOSSESWITHINCREASEDʅIGHTDURATION AREGENERALLYOBSERVED!LSO THEDECREASEINMUSCLESTRENGTHISCOMMONLYMOREPRO FOUNDINTHEEXTENSORTHANINTHEʅEXORMUSCLEGROUPSINTHELEGS4HISMAYBEDUETO THERESTPOSTUREINMICROGRAVITYSEE&IGURE WHICHSTRETCHESTHEDORSALʅEXOR MUSCLESTHEREBYMAINTAININGSIZEANDSTRENGTHOFTHESEMUSCLES

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Figure 5.12. This Photomicrograph Shows Normal Skeletal Muscle Fibers (Top) and Atrophied Skeletal Muscle Fibers (Bottom). Note the Marked Decrease in Size of the Atrophied Skeletal Muscle Below. (Credit NASA).

"ESIDESLOSSESINMUSCLEMASSANDMUSCLESTRENGTH LOSSESHAVEALSOBEENFOUNDIN MUSCULAR STAMINA AND CONTRACTILE ENDURANCE BOTH IN HUMANS AND IN RATS ;"ALDWIN ETAL =!GAIN THESEʄNDINGSWEREMADEINTHELEGS BUTNOTINTHEARMS!LTHOUGH THEUNDERLYINGMECHANISMMAYBEDIFFERENT THEREASONSFORTHESELOSSESARETHOUGHT TOBEIDENTICALTOTHEREASONSFORMAXIMALSTRENGTHLOSSESDISUSEDUETOUNLOADINGAND CONʄNEMENTINASMALLSPACE 

#HANGESINMUSCLESTRUCTURE

)TISWELLKNOWNTHAT ON%ARTH IFTHENERVEʄBERSCONNECTEDTOAMUSCLEARESEVERED ORTHEMOTORNEURONSDESTROYED THEDENERVATEDMUSCLEʄBERSBECOMEPROGRESSIVELY SMALLER THEIRCONTENTOFACTINANDMYOSINDECREASES ANDCONNECTIVETISSUEPROLIFERATES AROUNDTHEMUSCLEʄBERSDENERVATIONATROPHY !MUSCLECANALSOATROPHYWITHITS NERVESUPPLYINTACTIFITISNOTUSEDFORALONGPERIODOFTIME4HISPHENOMENONIS KNOWNASDISUSEATROPHY -USCLE WEAKNESS FOLLOWING SPACEʅIGHT IS CONSISTENT WITH THE REPORTED ǻ DECREASEINMUSCLEʄBERCROSS SECTIONALAREAANDTHELOSSOFCONTRACTILEPROTEINSISSPACE ʅOWNRATS;2ILEYETAL ="IOCHEMICALANDSTRUCTURALCHANGESATTHECELLULARAND MOLECULARLEVELSHAVEBEENSEENINMUSCLEBIOPSIESCOLLECTEDONASTRONAUTS(OWEVER THESESTUDIESAREVERYLIMITEDDUETOTHEPAINFULCHARACTEROFSUCHINVESTIGATION !NOTHER INDIRECT METHOD TO EVALUATE STRUCTURAL CHANGES IS MEASURING OXYGEN CONSUMPTION/XYGENUPTAKEANDENERGYEXPENDITUREARECLOSELYRELATED7HENSLOW TWITCH MUSCLES ARE EXERCISED THEY RELY PRIMARILY ON AN AEROBIC OXYGEN REQUIRING PROCESS TOEXTRACTTHEENERGYSTOREDINCARBOHYDRATES FATS ANDPROTEINS&AST TWITCH ʄBERS ARE MORE DEPENDENT ON ENERGY PRODUCED BY THE ANAEROBIC BREAKDOWN OF STORAGESOFGLYCOGEN)FAHUMANȀSMAXIMALOXYGENCAPACITYDECLINESINSPACE THE



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SLOW TWITCHMUSCLESMAYNOTBEASEFʄCIENTBECAUSEOFTHEIRINCREASEDDEPENDENCEON ANAEROBICENERGYSOURCES !NOTHERDIFʄCULTYININTERPRETINGDATAFROMHUMANSUBJECTSCOMESFROMTHEFACT THATTHETESTSUBJECTSPARTICIPATEINAWIDERANGEOFIN ʅIGHTPAYLOADACTIVITIES INCLUD ING%6! WHICHREQUIREVARIABLEANDUNDOCUMENTEDMUSCLEUSE!LSO AFURTHERASPECT THATMIGHTCONFOUNDTHEDATAISTHEUNKNOWNINʅUENCEOFTHEUNREPORTEDNUTRITIONAL STATUSOFTHEASTRONAUTS)TISLIKELYTHATCOSMONAUTSANDASTRONAUTSARETOSOMEDEGREE IN AN ENERGY DEʄCIT STATE DURING SPACEʅIGHT AT LEAST DURING THE SHORT DURATION MIS SIONSWITHAHEAVYSCHEDULE WITHTHECONSEQUENCEBEINGTHATMUSCLEPROTEINWILLBE LOST4HISPROBLEMBECOMESLESSIMPORTANTWITHINCREASINGMISSIONLENGTH ASINLONGER MISSIONS CREWMEMBERS HAVE MORE TIME TO PREPARE AND CONSUME FOOD AND CONSE QUENTLYGETCLOSERTOTHERECOMMENDEDDAILYENERGYINTAKE &ORTHESEREASONS MOSTSPACEʅIGHTINVESTIGATIONSONMUSCLEHAVEFOCUSEDONANI MALS GROWINGORMATURE)N ʅIGHTDISSECTIONSOFRODENTSKELETALMUSCLETISSUESHAVE SHOWN THAT ANTIGRAVITY SLOW TWITCH ʄBERS GENERALLY SHOW THE GREATEST DETERIORATION FOLLOWINGSPACEʅIGHT&IGURE )NFACTSLOWMUSCLEʄBERSSEEMSTOACQUIREFAST ʄBERPROPERTIES4HISSHIFTHASTHEDOWNSIDEOFRENDERINGTHEMUSCLEMOREFATIGABLE &IGURE 4HEGREATERRELIANCEONANAEROBICGLYCOLYSISCONTRIBUTESTOTHEREDUCED ENDURANCEANDINCREASEDFATIGABILITY "IOPSIESFROMTHECALFMUSCLES3OLEUSAND'ASTROCNEMIUS WERERECENTLYTAKEN FROMʄVE)33CREWMEMBERSFOLLOWINGSPACEʅIGHTSOFǻDAYS4HESETISSUESAM PLESALLOWEDFORDETERMINATIONOFTHECELLSIZEANDSTRUCTURALPROPERTIESOFINDIVIDUAL FAST AND SLOW MUSCLE ʄBERS 4HE SUBJECTS WERE ALSO TESTED ON A SPECIALLY DESIGNED TORQUE VELOCITY DYNAMOMETER TO MEASURE MUSCLE STRENGTH BEFORE AND AFTER ʅIGHT -ICROGRAVITYPRODUCEDADECREASEINTHEPEAKPOWEROFPOSTʅIGHTMUSCLEʄBER SAMPLES COMPARED TO PREʅIGHT MUSCLE ʄBER SAMPLES 4HIS DECREASE WAS DUE TO THE

Figure 5.13. These Light Micrographs Show the Effect of Microgravity on the Size and Type of Muscle Fibers in the Leg Muscles of Rats. The Larger Cells (Left) Are from the Muscle of a Rat That Remained on Earth and Served as a Control. The Smaller Cells (Right) Are from the Identical Muscle of a Spacelab-3 Rodent That Was in Earth Orbit for 8 days. The Dark-Stained Fast-Twitch Muscle Fibers Are More Numerous in the Muscle of the Flight Animal. (Credit NASA).

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Figure 5.14. Results of a 2 min Isometric Fatigue Test of Control and Flight Soleus Muscles of Rat. The Flight Muscles Were More Fatigable Than the Control Muscles, Presumably Because of Their Smaller Size and Their Changes to Fast-Twitch Properties. (Adapted from Baldwin et al. [1996]).

COMBINEDEFFECTSOFREDUCEDʄBERSIZEANDADECLINEINTHESIZEOFTHEMYOʄBRILSTHAT MAKEUPTHEʄBER;&ITTSETAL = &URTHEREXAMINATIONOFTHEDATATHATWERECOLLECTEDFROMTHECREWINDICATEDTHAT ASTRONAUTSWHOPERFORMEDAHIGHERLEVELOFTREADMILLEXERCISEGREATERTHANMIN WEEK VSLOW LEVELTREADMILLEXERCISELESSTHANMINWEEK EXHIBITEDASMALLER DECREASE IN PEAK POWER !STRONAUTS WHO PERFORMED HIGH LEVEL TREADMILL EXERCISE SHOWEDADECREASECOMPAREDTOADECREASEINPEAKPOWEROFASTRONAUTSWHO PERFORMEDLOWLEVELTREADMILLEXERCISE3AMPLEANALYSISOFTHEMUSCLEʄBERSINDICATED THATTHERATIOOFMYOSINANDACTINPROTEINSINTHEMUSCLEʄBERSWASNOTAFFECTEDBY LONG DURATIONSPACEʅIGHT!LTHOUGHEXERCISESLOWEDTHEONSETOFATROPHYANDLOSSOF STRENGTHINMUSCLEʄBERS ASIGNIʄCANTAMOUNTOFMUSCLEVOLUMEANDSTRENGTHLOSSSTILL OCCURREDONLONG DURATIONMISSIONS;'ALLAGHERETAL = !LTHOUGH REDUCED USE SUCH AS OCCURS DURING SPACEʅIGHT DECREASES MUSCLE SIZE AND STRENGTH CONTRACTILE PROTEINS SEEM TO ADJUST TO MAINTAIN POWER OUTPUT 5PON RETURN TO %ARTH TERRESTRIAL MOTOR STRATEGIES ARE RAPIDLY RESTORED AND EXECUTED ʅAW LESSLY 4HIS OCCURS WELL BEFORE MUSCLE ʄBER RE GROWTH IN CROSS SECTIONAL AREAS AND DURINGTHEPERIODOFSLOWMUSCLEʄBERNECROSIS)TTHENAPPEARSTHATTHECENTRALNER VOUSSYSTEMUNDERGOESSIGNIʄCANTRE PROGRAMMINGPLASTICITY ANDPERFORMSCOMPEN SATORY ACTIVATION OF MOTOR UNITS THAT MASKS THE DETERIORATED STATE OF THE MUSCULAR SYSTEM;2ILEYETAL =

 %FFECTSOFSPACEʅIGHTONBONE "ECAUSEOFTHEABSENCEOFGRAVITYCONSTRAINTSONTHEBODY ASTRONAUTSCANLOSEUPTO OFTHEIRBONEMINERALDENSITYEACHMONTH4HEBONELOSSOBSERVEDAFTERASPACEʅIGHT OFAFEWMONTHSCORRESPONDSTOTHATOFSEVERALYEARSONTHEGROUND"YCOMPARISON

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WITH OSTEOPOROSIS ON %ARTH ASTRONAUTS COULD THEREFORE BE CONSIDERED AS ȃHYPER SEDENTARYȄPERSONS)TWASRECOGNIZEDLONGAGOTHATUNDERSTANDINGTHEFUNDAMENTAL BIOCHEMISTRYANDPHYSICSOFBONEMINERALIZATIONON%ARTHISNECESSARYTOFULLYUNDER STAND THE POTENTIAL EFFECTS IN MICROGRAVITY ENVIRONMENTS ;(ATTNER AND -C-ILLAN =4HEOPPOSITEISALSOTRUE 

(UMANSTUDIES

4HE MAIN MINERAL IN BONE IS CALCIUM WHICH MAKES CALCIUM BALANCE AN IMPORTANT DETERMINANTOFTHESTATUSOFBONEMINERALDENSITY&IGURE !NINCREASEINTHE FECALANDURINARYCALCIUMEXCRETIONWASʄRSTNOTICEDAFTERTHE3OVIET6OSTOKMISSIONS #ALCIUM IN URINE AND FECES INCREASED DRASTICALLY IN 3KYLAB ASTRONAUTS PARALLEL TO A MUSCLEANDBONELOSS;,EACHAND2AMBAUT =!NAGGRESSIVEEXERCISEPROGRAM WASTHENIMPLEMENTED WITHSIGNIʄCANTCONSEQUENCESFORMUSCLEVOLUME $URINGTHE'EMINIMISSIONS BONEMINERALDENSITYWASDETERMINEDBYX RAYDENSI TOMETRY WHICHMEASURESTHEATTENUATIONOFTWOBEAMSOFX RAYSBYTHECALCIUMINTHE X RAYPATH7ITHTHISTECHNIQUE WHICHHASAPRECISIONOFǻ ALOSSOFAPPROXI MATELYǻOFBONEMASSWASDETECTEDINTHEHEELBONEAFTERǻDAYSOFSPACE ʅIGHT4HESUBSEQUENT!POLLO 3KYLAB AND3ALYUTDATAWEREOBTAINEDBYSINGLEPHOTON ABSORPTIOMETRY!FTERTHE!POLLOMISSIONSALSOLASTINGDAYS AǻDECREASEIN BONEMASSWASOBSERVED4HEREFORE ǻDAYSSPENTONTHE-OONSURFACEATGDID NOTPREVENTBONELOSS!FTER3OYUZMISSIONS BONEDENSITYHADDECREASEDBYǻ 3KYLABMEASUREMENTSREVEALEDAǻPERMONTHLOSSINBONEMINERAL #OSMONAUTS ON BOARD -IR WERE EXAMINED WITH QUANTITATIVE COMPUTERIZED TOMOGRAPHY1#4 WHICHGIVESATRUE VOLUMETRICDENSITYINGCM 2ESULTSSHOWED A  LOSS OF TRABECULAR BONE FROM LUMBAR SPINE AFTER A  YEAR MISSION /THER CREWMEMBERS WERE EXAMINED BOTH PRE AND POSTʅIGHT USING DUAL ENERGY 8 RAY ABSORPTIOMETRY$%8! $%8!ISASPECIALLYCALIBRATED8 RAYDEVICETHATPROVIDESA

Figure 5.15. Increased Urinary Calcium Excretion Observed in Astronauts in Skylab and Other Flights. Calcium That Is Flushed Out by the Kidneys with the Rest of the Urine Could Form Stones That May Need to Be Removed by Surgery.

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TWO DIMENSIONALMEASUREMENTOFTHEMASSOFANENTIREBONE IE THETRABECULARBONE ANDTHECORTICALBONE4HESESCANSREVEALEDTHATWHENUSINGONBOARDEXERCISECOUNTER MEASURES THEREWASADECREASEINBONEDENSITYINTIBIA"ONEDENSITYDIDNOT RETURN TO PREʅIGHT LEVEL IN SOME INDIVIDUALS 7ITHOUT COUNTERMEASURES THERE WAS APPROXIMATELY ǻ PER MONTH DECREASE IN BONE DENSITY )N THE WORST CASE A ǻ DECREASE WAS MEASURED IN SOME BONES AFTER A  MONTH MISSION ;,E"LANC ETAL = 4HEMOSTCOMPELLINGDATAHAVEBEENCOMPILEDFROMCOSMONAUTSWHOSPENT  ORMONTHSONTHE-IRSTATION;6ICOETAL ="ONEMINERALDENSITYWASMEA SUREDATTHEDISTALRADIUSANDTIBIABEFORE JUSTAFTERTHESPACEʅIGHTTHROUGHMONTHS AFTERTHEMISSION.EITHERTRABECULARNORCORTICALBONEOFTHERADIUSWASSIGNIʄCANTLY CHANGEDATANYOFTHETIMEPOINTS/NTHECONTRARY INTHEWEIGHT BEARINGTIBIALSITE TRABECULARBONELOSSWASNOTEDAFTERA MONTHʅIGHT ANDWASGREATERAFTERA MONTH ʅIGHT4IBIALBONELOSSPERSISTEDFORATLEASTMONTHSAFTERʅIGHT SUGGESTINGTHATTHE TIMENEEDEDTORECOVERISLONGERTHANTHEMISSIONDURATION&IGURE  /NTHE)33 BONEMINERALDENSITYISLOSTATANAVERAGERATEOFABOUTPERMONTH INTHELUMBARSPINEANDPERMONTHINTHEFEMORALNECK!SSESSEDWITH1#4 LOSSES OFMASSINTHECORTICALBONETHEBONEȀSDENSEOUTERLAYER OFTHEHIPAVERAGEAROUND ǻPERMONTH WHEREASLOSSESINTHETRABECULARBONETHEBONEȀSINNER SPONGY LOOKINGLAYER AVERAGESǻPERMONTH;,ANGETAL =$URINGMISSIONSOF  MONTH DURATION ASTRONAUTS EXPERIENCE AN AVERAGE OF  DECLINE IN FEMORAL BONE MASS"ONEMASSANDSTRUCTUREOFTHEASTRONAUTSȀFEMURSRECOVER BUTNOTFULLY AFTER YEARBACKON%ARTH7HILEBONEMASSANDVOLUMEINCREASEBACKON%ARTH THEVOLUMET RICBONEMASSDENSITYDOESNOTFULLYRECOVERPROXIMALFEMURISLARGERINSIZE BUTLESS MINERALIZEDANDMOREPOROUSTHANBONELOSTDURINGSPACEʅIGHT ;,ANGETAL =

Figure 5.16. Mean Loss of Bone Mineral Density in the Radius and the Tibia Relative to Preflight Values in Cosmonauts Following Spaceflights of 6 Months on Board Mir. In Some Individuals the Bone Loss Continues for About 6 Months After Flight. (Adapted from Vico et al. [2000]).

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)N A RELATED FOLLOW ON STUDY 3IBONGA ET AL ;= EXAMINED THE BONE MINERAL D ENSITY$%8!MEASUREMENTSINʄVEBODYSITESFORCREWMEMBERS BOTH53AND 2USSIAN WHOPARTICIPATEDONLONG DURATIONʅIGHTSOFATLEAST MONTHDURATION 4HESTUDYPOPULATIONSHOWEDVARIABLEDECREASESINBONEMASSDENSITYACROSSTHEʄVE SITES4HEKEYRESULTWASTHATTHEYCOULDCALCULATEANESTIMATEFORTIMEREQUIREDTO RESTOREOFTHELOSSOFBONEINEACHSITE ANDTHATFULLRECOVERYWOULDTAKEUPTO YEARSǻMUCHLONGERTHANTHEMISSIONDURATION .OSIGNIʄCANTCHANGESINTHEBONEREGULATINGHORMONES SUCHASSERUMCALCIUM 04( VITAMIN$ CALCITONIN ANDGROWTHHORMONE HAVEBEENSEENONASTRONAUTSAFTER SHORT DURATIONSHUTTLEʅIGHTS;3TEINETAL =4HEDURATIONOFSTAY CALCIUMINTAKE AND LEVEL OF EXERCISE PERFORMED IN ʅIGHT ALL ACCOUNT FOR THE WIDE RANGE IN AVERAGE PERCENTAGELOSSESOFBONEMINERALDENSITY ASREPORTEDABOVE)NDIVIDUALVALUESARE EVENMOREVARIABLE ASCHANGESINCALCANEALBONEDENSITYOFONEPARTICULARSUBJECTCAN RANGEFROMTOLOSSRELATIVETOPREʅIGHT!METHODALLOWINGBOTHIDENTIʄCATION OFTHERECORDEDSITEANDREPRODUCIBLEMEASUREMENTSAREREQUIREDFORMOREACCURATE STUDIES #OMPLEMENTING THE $%8! AND 1#4 TECHNIQUES ARE MAGNETIC RESONANCE IMAGERY-2) EXAMINATIONSBEINGPERFORMEDPRE ANDPOSTʅIGHTWITHTHE)33CREW MEMBERS4HESESTUDIESWILLPROVIDETHEʄRSTDETAILEDINFORMATIONONTHEDISTRIBUTION OFSPACEʅIGHT RELATEDBONELOSSBETWEENTHETRABECULARANDCORTICALCOMPARTMENTSOF THESKELETON ASWELLASTHEEXTENTTOWHICHLOSTBONEISRECOVEREDINTHEYEARFOLLOWING RETURN&IGURE  

!NIMALSTUDIES

/NEPROBLEMOFUSINGRODENTSASMODELSISTHATTHEIRBONEGROWTHISDIFFERENTFROM HUMANS!LTHOUGHBONEELONGATIONCEASESINHUMANSAFTERPUBERTY INMICETHEEPI PHYSESNEVERCLOSEANDTHEREISCONTINUOUSLONGITUDINALGROWTH)NRATS THEGROWTH

Figure 5.17. Website of the Canadian Space Agency Body Scan Booth Describing the Experiments on Bone and Muscle During ISS Expedition-20–21 with Astronaut Bob Thirsk. (Source: http://www.asc-csa.gc.ca/eng/missions/expedition20-21/ body_scan.asp#).

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RATEISSIGNIʄCANTLYATTENUATEDATABOUTǻMONTHSOFAGETHEYLIVETOABOUTǻ YEARSOLD BUTTHEIRCORTICALBONE WHICHLACKSVASCULARCANALS ISNOTSIMILARTOTHATOF HUMANS )NEARLY3OVIET#OSMOSʅIGHTS VARIOUSTYPESOFMUSCLEʄBERSWEREFOUNDINʅOWN RATS TOGETHERWITHHISTOLOGICCHANGESWITHRANDOMDELETIONOFMYOʄBRILLARʄLAMENTS ;"ALLARD AND #ONNOLLY = 4HERE WAS A LOSS OF MUSCLE FORCE AND ELASTICITY AND SOMESPECIʄCCHANGESINENZYMEACTIVITY!REDUCTIONINTHERATEOFBONEFORMATION WASOBSERVEDPOSTʅIGHT WITHARETURNTOCONTROLLEVELSINAPPROXIMATELYWEEKS)TIS INTERESTINGTONOTE HOWEVER THATTHESECHANGESWERELARGELYPREVENTEDINTHERATSTHAT WERESUBJECTEDTOCENTRIFUGATIONIN ʅIGHT;.ICOGOSSIANAND0ARKER = 3TUDIESONYOUNGRATSʅOWNONBOARD3PACELABMISSIONSREVEALEDNOCHANGESIN THELENGTHOFANTIGRAVITYBONES SUCHASTHETIBIA THEFEMUR ANDTHEHUMERUS COM PARED TO GROUND CONTROL ANIMALS )N OTHER WORDS THE RATS GREW AT THE SAME RATE IN MICROGRAVITYASON%ARTH(OWEVER THEBONEMASS HENCEITSSTRENGTH WASREDUCED !NANIMALMODELUSEDTOSTUDYMUSCLEATROPHYANDBONELOSSISTHESUSPENDEDRAT &IGURE 4HEMODELINCORPORATESTHETWOFEATURESOFSPACEʅIGHTTHATMIGHTAFFECT BONE THE UNLOADING OF WEIGHT BEARING BONES AND THE HEADWARD ʅUID SHIFT )N THIS PREPARATION A HARNESS RAISES THE HIND LIMBS OFF THE CAGE ʅOOR AND THUS ȃREMOVESȄ WEIGHTFROMTHEMUSCLESOFTHEHINDLIMBS4HEOVERHEADPULLEYSYSTEMHASASWIVEL THATALLOWSTHEANIMALTOMOVEABOUTTHECAGEBYONLYUSINGITSFORELIMBS!FTERAFEW DAYSOFADAPTATION TAIL SUSPENDEDANIMALSAREACTIVEANDEATANDDRINKNORMALLY4HIS RELATIVELYBENIGNTECHNIQUEISRELATIVELYRAPIDANDREPRESENTSANACCURATESIMULATIONOF THECHANGESINMUSCLEANDBONEOCCURRINGDURINGSPACEʅIGHT;4ISCHLERETAL  0ICQUETAND&ALEMPIN = .EITHER THE COMMUNICATION SYSTEM BETWEEN MUSCLE AND BONE NOR THE PRECISE MECHANISMOFBONELOSSISUNDERSTOOD4HEREFORE THECHARACTERIZATIONOFTHERESPONSE

Figure 5.18. The Rat Hind Limb Suspension Technique Is Widely Used to Simulate the Unloading of Muscle and Bone as During Spaceflight [Lujan and White, 1994].



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TOSKELETALUNLOADINGATTHETISSUEANDCELLULARLEVELISONEOFTHEMAJORCONTRIBUTIONS OFTHEUSEOFTHERATMODEL;-OREY (OLTONAND'LOBUS =&OREXAMPLE RECORDING OF3OLEUSMUSCLEACTIVITYOFSUSPENDEDRATSSHOWEDANIMMEDIATEANDPERSISTENT REDUCTIONINCONTRACTILEACTIVITY!FTERDAYS THE3OLEUSMUSCLESHOWEDADECREASEIN SPECIʄCTENSIONASSLOWʄBERSSHIFTEDTOWARDFASTʄBERSANDTHICK MYOSIN CONTAINING ʄLAMENTSWERELOST;2ILEYETAL =4HESEANIMALSALSOLOSEABOUTOFTRABECU LARBONEINTHETIBIA ANDSHOWEDAREDUCTIONINTHEMECHANICALSTRENGTHOFTHE TIBIASHAFT;6ICOETAL = 5NLOADING STUDIES WITH IMMATURE RATS INDICATE THAT GRAVITY LOADING DURING THE THIRDANDFOURTHWEEKSAFTERBIRTHISESSENTIALFORNORMALDEVELOPMENTOFLOCOMOTION ;7ALTON =3IMILARLY MUSCLEDEVELOPMENTWASDISRUPTEDWHENGRAVITY LOADING EXERCISEWASREMOVEDFROMIMMATURERATSʅOWNONTHE.EUROLABʅIGHT)NTHEABSENCE OFWEIGHT BEARINGCHALLENGE 3OLEUSMUSCLEʄBERSFAILEDTOGROWINSIZEANDDIFFEREN TIATE NORMALLY INTO SLOW ʄBERS AND ELABORATION OF THE MOTOR NERVE TERMINALS WAS RETARDED/NCEMATURE MUSCLETISSUEINUNLOADEDANIMALSISMOREPRONETOSTRUCTURAL FAILURE WHEN RELOADED BECAUSE OF ʄBER ATROPHY AND THE ABILITY TO REPAIR INTERNAL LESIONSISCOMPROMISED;!RNAUDETAL =4HEROLEOFʄBER TYPESPECIʄCFACTORS IN REGULATING GENE EXPRESSION IS BEING STUDIED IN TRANSGENIC ANIMALS ;#APETANAKI ETAL =

 7HATDOWEKNOW  -USCLEATROPHY 4HE HUMAN BODY CONSTANTLY USES AMINO ACIDS TO BUILD MUSCLE PROTEIN WHICH THEN BREAKSDOWNANDMUSTBEREPLACED7HENPROTEINTURNOVERGETSOUTOFBALANCE SOTHAT MOREPROTEINBREAKSDOWNTHANTHEBODYCANREPLACE THERESULTISMUSCLELOSS"UT WHATCAUSESPROTEINTURNOVERTOSLOWDOWN /NECAUSEISLACKOFMUSCULARACTIVITY4HATISWHYBEDRESTISAGOODMODELBECAUSE ITMINIMIZESACTIVITY)NFACT DURINGBEDRESTTHEREISANINCREASEDURINARYEXCRETIONOF NITROGENANDMUSCLELOSS JUSTLIKETHATOBSERVEDINSPACE BUTTHESECHANGESAREVARI ABLEANDGENERALLYGREATERINDEGREE-OSTOFTHEATROPHYOCCURSINANTIGRAVITYMUSCLES WHICHARENOLONGERBEARINGBODYWEIGHT/FTHESEVARIOUSPOSSIBLEFACTORSCONTRIBUT INGTOTHEEXCESSEXCRETIONOFNITROGEN MUSCLEATROPHYISCLEARLYTHEMAINONE )N ALL LONG DURATION ASTRONAUTS THE HIGH LEVEL OF NITROGEN EXCRETION CONTINUED UNABATEDFORTHEDURATIONOFʅIGHT4HISINDICATESASERIOUSMALFUNCTIONNOTLIKELYTO REACHANEWSTEADYSTATEUNTILANEXTREMEDEGREEOFATROPHYISREACHED4HISNITROGEN LOSSWASACCOMPANIEDBYLOSSESOFǻOFMUSCLEMASSANDSTRENGTHINTHELOWER EXTREMITIES4HISPOSESASIGNIʄCANTHANDICAPTOVIGOROUSWORKINTHEGRAVITYOF-ARS ORONRETURNTO%ARTH !NIMAL STUDIES OF MUSCLE ATROPHY ATTEMPT TO DETERMINE THE PHYSIOLOGICAL AND BIOCHEMICALMECHANISMSUNDERLYINGMUSCLEATROPHY!LTHOUGHTHEMECHANISMOFTHE PROCESSOFATROPHYREMAINSUNKNOWN CERTAINASPECTSHAVEBECOMEEVIDENT-USCLE ATROPHYISACCOMPANIEDBYDECREASEDSYNTHESISOFMUSCLEPROTEINANDBYSOMEDEGREE OF INCREASED DEGRADATION !S SHOWN IN SUSPENDED RATS WITH HIND LIMB UNLOADED LOADINGANDSTRETCHINGOFOTHERWISEINACTIVELEGMUSCLESPREVENTEDMUSCLEATROPHY

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AND STIMULATED PROTEIN SYNTHESIS 4HE ADDITION OF ELECTRICAL STIMULATION INCREASED PROTEINSYNTHESISMARKEDLY!SSHOWNINMUSCLECELLCULTURES STRETCHINGSTIMULATES PROTEINSYNTHESIS 4HEUNCERTAINVALUEOFPHYSICALEXERCISEFORSUPPRESSINGMUSCLEATROPHYINHUMAN SPACEʅIGHTHASBEENNOTEDPREVIOUSLY(OWEVER WHATISTHESIGNALANDSEQUENCEOF BIOCHEMICALSTEPSFORINITIATINGINCREASEDPROTEINSYNTHESISANDDEPOSITIONINMUSCLE ʄLAMENTS ANDWHATCOMMUNICATESAMESSAGETOSLOWDOWNPROTEINSYNTHESIS!NSWERS TO THESE QUESTIONS WOULD CERTAINLY HAVE AN IMPACT ON MUSCLE RESEARCH FAR BEYOND SPACEʅIGHT 4HEEFFECTSOFELECTRICALSTIMULATIONOFMUSCLEHAVEBEGUNTOBESTUDIED BUTTHE POSSIBLE COMBINATIONS OF FREQUENCY VOLTAGE AND CURRENT ARE ALMOST WITHOUT LIMIT 3TIMULATION OF THE SOLE CUTANEOUS MECHANORECEPTORS SEEMS TO REDUCE THE MUSCULAR ATROPHYAFTERHINDLIMBUNLOADINGINRATS;$E $ONCKERETAL = ! VARIETY OF TECHNIQUES ARE AVAILABLE FOR MUSCLE RESEARCH ELECTRON MICROSCOPY ELECTROMYOGRAPHY COMPUTERIZEDTOMOGRAPHYSCANNING ANDSTABLEISOTOPEMETABOLIC STUDIES4OUNDERSTANDCHANGESOFMUSCLEMASSANDSTRENGTH WEMUSTʄRSTUNDERSTAND THEIRUNDERLYINGCELLULARANDMOLECULARMECHANISMS4HEREFORE THESEEXISTINGTECH NOLOGIESSHOULDBECOUPLEDWITHDEVELOPINGTECHNIQUESINIMMUNOCHEMISTRYANDIN RECOMBINANT $.! AND GENE CLONING 4HE GENES ENCODING MANY MAJOR PROTEINS OF MUSCLE ASWELLASTHEIRCONTROLLINGELEMENTS HAVEBEENSEQUENCED4HECURRENTGOAL ISTORELATEMECHANICALSTRESS HORMONALLEVELS ANDNUTRITIONTOTHECONTROLOFEXPRES SIONOFTHESEGENES 

"ONEDEMINERALIZATION

(UMANBEDRESTSTUDIESCORRELATINGINACTIVITYTOFACTORSSUCHASDIMINISHEDBONEMASS AND INCREASED URINARY CALCIUM HAVE ALSO PROVEN TO BE USEFUL MODELS FOR POTENTIAL CHANGESDURINGEXTENDEDSPACEʅIGHT3TUDIESOFHUMANSDURINGLONG DURATIONBEDREST HAVESHOWNTHATPROLONGEDINACTIVITYRESULTSINSIGNIʄCANTANDCONTINUINGLOSSESOF CALCIUMFROMTHESKELETONANDNITROGENFROMMUSCLE ANDINCONSIDERABLEATROPHYOF BOTHBODYSYSTEMS4HESECHANGESWERECONSISTENT BUTQUITEDIFFERENTINDEGREEFROM SUBJECTTOSUBJECT'ENETICFACTORSMAYACCOUNTFORTHESEDIFFERENCES(OWEVER ASOF YET NOSINGLEGENEHASBEENCONVINCINGLYPROVENTOBEARISKFACTORFOROSTEOPOROSIS 4HEGENETICCOMPONENTHASBEENATTRIBUTEDINSTEADTOTHECUMULATIVEEFFECTSOFANUM BEROFGENES INCLUDINGFOREXAMPLETHEVITAMIN$RECEPTORGENE WITHSMALLINDIVIDUAL EFFECTS)DENTIʄCATIONOFSUCHGENESISCURRENTLYUNDERWAY;4IPTON = )NTHESEVEREPARALYSISOFPOLIOMYELITIS CALCIUMLOSSESLEDTOX RAYVISIBLEOSTEOPO ROSISINTHEBONESOFTHELOWEREXTREMITIESASEARLYASMONTHSAFTERPARALYSIS7HILE THEOVERALLRATEOFCALCIUMLOSSIN3KYLABASTRONAUTSWASOFTOTALBODYCALCIUM PERMONTH THELOSSWASESTIMATEDTOBETENTIMESGREATERINTHELOWEREXTREMITIESTHAN INTHERESTOFTHEBODY BASEDONBEDRESTSTUDIESOFCALCIUMLOSSESBYMETABOLICBAL ANCECOMPAREDWITHDECREASEINBONECALCIUMDENSITY4HISCOULDLEADINMONTHSOF ʅIGHT TO A DECREASE IN BONE DENSITY IN THE LEGS SIMILAR TO THAT NOTED IN PARALYTIC POLIOMYELITIS 3TUDIESOFIMMOBILIZEDRABBITSSHOWEDMARKEDDECREASEINSTRENGTHOFTENDONSAND LIGAMENTSAFTERONLYMONTH4HUS STRAINS SPRAINS ANDEVENLIGAMENTTEARSMAYBE MORELIKELYTOOCCUR ANDATANEARLIERTIMETHANBONEFRACTURES



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4HECELLULARMECHANISMSOFMINERALLOSSAREUNKNOWN%XCESSEXCRETIONOFCALCIUM ASSOCIATED WITH INCREASED HYDROXYPROLINE IN THE URINE IN HUMANS IS INDICATIVE OF INCREASEDBONERESORPTION/NTHEOTHERHAND HISTOLOGICEXAMINATIONOFTHEBONESOF THERATSON#OSMOSSHOWEDSUPPRESSEDBONEFORMATION-ANYSCIENTISTSBELIEVETHAT BONEMASSDECREASESINMICROGRAVITYBECAUSETHELACKOFSTRESSONTHEBONESSLOWSTHE FORMATIONOFOSTEOBLASTCELLS&EWERBONE BUILDINGCELLS ALONGWITHACONSTANTLEVELOF BONE DESTROYINGACTIVITY WOULDTRANSLATEINTOANETLOSSOFBONEMASS"UTWHYSHOULD MICROGRAVITYINHIBITTHEDEVELOPMENTOFOSTEOBLASTS!KEYCHEMICALINTHEDEVELOP MENTOFOSTEOBLASTCELLSFROMPRECURSORCELLSISANENZYMECALLEDȃCREATINEKINASE "Ȅ )NVESTIGATORSARETRYINGTOʄGUREOUTWHICHMOLECULESINTHEBODYREGULATETHEACTIVITY OFTHISENZYMEANDHOWTHOSECHEMICALSAREAFFECTEDBYREDUCEDGRAVITY INTHEHOPE THATTHISKNOWLEDGEWILLPOINTTOAWAYTOBOOSTOSTEOBLASTFORMATIONINSPACE )NANYCASE THEHYPERCALCIURIAASSOCIATEDWITHLOSSOFMINERALFROMBONEINSPACE ʅIGHTMIGHTINCREASETHEPOTENTIALFORSTONEFORMATIONINTHEURINARYTRACT!LTHOUGH ǻOFRENALSTONESCONTAINCALCIUM THELIKELIHOODOFSTONEFORMATIONWILLDEPEND NOTONLYONINCREASEDURINARYCONCENTRATIONOFCALCIUM BUTALSOONOTHERFACTORSSUCH ASURINARYP( CONCENTRATIONOFTHEINORGANICELEMENTSMAGNESIUM POTASSIUM AND PHOSPHORUS AND CONCENTRATIONS OF THE ORGANIC COMPOUNDS URIC ACID CITRATE AND OXALATE"EDRESTSTUDIESHAVESHOWNASLIGHTRISEINURINARYP(ANDALACKOFCHANGE INURINARYCITRATE WHICHINAMBULATORYSTATESRISESWITHINCREASESINURINARYCALCIUM "OTHOFTHESEFACTORS IFALSONOTEDINSPACEʅIGHT WOULDFAVORDECREASEDSOLUBILITYOF CALCIUMSALTS4HELIKELIHOODOFURINARYTRACTSTONEFORMATIONDURINGSPACEʅIGHTMAY BESMALL ESPECIALLYIFCAREISTAKENTOMAINTAINABUNDANTURINEVOLUMESNEVERTHELESS SUCHSTONEFORMATIONMIGHTBECATASTROPHICTOHEALTHANDFUNCTIONFORTHEASTRONAUT INVOLVED ANDTHUSTOSUCCESSOFTHEPARTICULARʅIGHT .!3! HAS DEVELOPED A (UMAN 2ESEARCH 2OADMAP (22 ;HTTPHUMANRE SEARCHROADMAPNASAGOV= TO GUIDE ITS BIOASTRONAUTICS RESEARCH IN SYSTEMATICALLY REDUCINGORELIMINATINGTHERISKSTOASTRONAUTHEALTH SAFETY ANDPERFORMANCEDURING ANDAFTERSPACEʅIGHT/FTHERISKSIDENTIʄEDINTHISCRITICALPATHROADMAPFORHUMAN SPACEEXPLORATION ATLEASTAREASSOCIATEDWITHALTEREDMUSCULO SKELETALFUNCTIONSEE #HAPTER 4ABLE /FPARTICULARCONCERNSISTHEACCELERATIONOFAGE RELATEDOSTEO POROSIS THEFAILURETORECOVERBONELOSTAFTERSPACEMISSIONS ANDTHEINCREASEDRISKOF FRACTUREUPONRETURNTOACTIVITYING#RITICALQUESTIONSTOBEADDRESSEDINCLUDE A 7ILL BONE MASS LOSS CONTINUE UNABATED FOR MISSIONS GREATER THAN  MONTHS IN DURATION ORWILLITEVENTUALLYPLATEAUATSOMETIMECONSISTENTWITHABSOLUTEBONE MINERALDENSITY B 7HATARETHEMOSTIMPORTANTPREDICTORSFORBONELOSSDURINGPROLONGEDEXPOSURE TO HYPOGRAVITY ESPECIALLY WITH REFERENCE TO ETHNICITY GENDER AGE AND BONE MORPHOMETRY C )SBONELOSSREVERSIBLEANDWITHINWHATTIMEFRAME D $OESPROLONGEDEXPOSURETOHYPOGRAVITYLEADTONON UNIONOFHEALINGFRACTURES 7HATEVIDENCESUPPORTSTHEALTERATIONINVERTEBRALMORPHOMETRYDURINGANDAFTER EXTENDEDSPACEʅIGHT E 7HAT PRACTICAL DIAGNOSTIC TOOLS CAN BE UTILIZED DURING MULTI YEAR MISSIONS TO MONITORANDQUANTIFY8 RAYABSORPTIOMETRY ULTRASOUND

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F !RETHEREOTHERIMPORTANTMECHANISMSFORBONELOSSWITHHYPOGRAVITYTHATARE CRITICAL TO DEVELOPING EFFECTIVE COUNTERMEASURES EG ʅUID SHIFTS WITH ALTERED HYDROSTATICPRESSURE CHANGESINBLOODʅOW IMMUNESYSTEMALTERATIONS  G )STHEREANOPTIMALCOMBINATIONOFEXERCISEANDAPHARMACOLOGICALCOUNTERMEA SURETOMINIMIZEDECREMENTSINBONEMASSINHYPOGRAVITY

 #OUNTERMEASURES 4HEONLYCOUNTERMEASURETHATISUSEDCONSISTENTLYTODATETOCOUNTERACTTHESKELETAL MUSCLE ATROPHY AND LOSS OF MUSCLE STRENGTH AND ENDURANCE THAT IS ASSOCIATED WITH MICROGRAVITY EXPOSURE IS PHYSICAL EXERCISE &OR LONG DURATION MISSIONS ABOARD THE )33 53CREWMEMBERSAREREQUIREDTOCOMPLETEA HBOUTOFCOMBINEDAEROBIC AND RESISTANCE EXERCISE ON  OF  DAYS DURING THEIR ASSIGNED MISSION 4HIS PERIOD INCLUDESTHETIMETHATISNEEDEDFORHARDWARESETUP STOWAGE ANDPERSONALHYGIENE 4YPICALLY THROUGH APPROXIMATELYHWEREDEVOTEDTORESISTIVEEXERCISEONTHE INTERIM2ESISTIVE%XERCISE$EVICEI2%$ &IGURE ANDAFURTHERAPPROXIMATELY HWASDEVOTEDTOEITHERTHE4READMILLWITH6IBRATION)SOLATION3YSTEM46)3 ORTHE

Figure 5.19. The Interim Resistive Exercise Device (iRED) on Board the ISS. The Astronauts Can Pull on a Cord to Create Resistance (Right), or Use a Shoulder Harness System to Do Deep Knee Bends, Which Stimulate the Anti-Gravity Muscles (Left). (Credit NASA).

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#YCLE%RGOMETERWITH6IBRATION)SOLATION3YSTEM#%6)3 ORACOMBINATIONOFTHE TWO 3INCE  AN ADVANCED 2ESISTIVE %XERCISE $EVICE A2%$ HAS REPLACED THE I2%$ /N DAYS WHEN CREWMEMBERS ARE SCHEDULED TO CONDUCT %6!S THEY ARE NOT SCHEDULEDFOREXERCISE GIVENTHAT%6!STYPICALLYREQUIREASIGNIʄCANTAMOUNTOFTHE DUTYDAYANDSTRENUOUSPHYSICALEFFORT)TISINTERESTINGTONOTETHAT2USSIANCREWMEM BERSAREREQUIREDTOCOMPLETEDIFFERENTREGIMENSOFEXERCISE USINGTHEIROWNEQUIP MENT ATREADMILLANDACYCLEERGOMETER 

-USCLE

4HECONSIDERABLEANDTIME CONSUMINGEXERCISEACTIVITYOFTHEASTRONAUTSON3KYLAB AND-IRRESULTEDINSOMEWHATREDUCEDLOSSOFMUSCLEMASSANDSTRENGTHTHANONTHE EARLIERʅIGHTS BUTWEREOBVIOUSLYNOTADEQUATETOBEFULLYPROTECTIVE&LIGHTSURGEONS RECOMMENDEDONLYMINOFEXERCISEDAILYONSHORT DURATIONMISSIONS COMPAREDTO THECURRENTHONLONG DURATIONMISSIONS4HECURRENTSUITEOFEXERCISEEQUIPMENT ANDTHEASSOCIATEDEXERCISEREGIMENSDONOTTARGETMAINTENANCEOFASPECIʄCLEVELOF SKELETALMUSCLESTRENGTHORENDURANCE NORARETHEYPARTICULARLYOPTIMIZEDTOPRODUCE BENEʄCIALRESULTSINTHESHORTESTTIMEPOSSIBLE 4HETREADMILLMAYBEUSEDFORWALKINGANDRUNNINGTOPRESERVEANAEROBICPOWER SEE &IGURE   4HERE ARE TWO TREADMILLS ON BOARD THE )33 ONE IN THE (ARMONY .ODE AND ONE IN THE :VEZDA MODULE 4HE 53 TREADMILL IS NAMED #OMBINED /PERATIONAL,OAD"EARING%XTERNAL2ESISTANCE4READMILL#/,"%24 AFTERCOMEDIAN 3TEPHEN#OLBERT&IGURE 4HEDEVICEEMPLOYSVARIOUSSTRATEGIESTOSIMULATE AS CLOSELY AS POSSIBLE  G SKELETAL LOADING DURING EXERCISE ,OADS ARE EXERTED ON THE SUBJECTBYRESTRAINTHARNESSES4HERESTRAINTSYSTEMPROVIDESSTABILIZATIONOFTHEASTRO NAUTANDLOADDISTRIBUTIONONTHEBODYINAWEIGHTLESSENVIRONMENT4HETREADMILLCAN BEMOTOR DRIVENORPASSIVELYOPERATED3O ITISUSEDASANAMBULATINGTRAINER ENDUR ANCE EXERCISE OF POSTURAL MUSCULATURE HIGH IMPACT SKELETAL LOADING BONE MAINTE NANCE AND AEROBIC EXERCISE -OVING AIR FROM A NEARBY DUCT IS USED TO DRY THE PERSPIRATIONPRODUCEDFROMEXERCISING 4HECYCLEERGOMETERISTOPRESERVEAEROBICCAPACITYSEE&IGURE )TPROVIDES WORKLOAD DRIVEN BY THE HANDS OR FEET WHICH IS CONTROLLED BY MANUAL OR COMPUTER ADJUSTMENT)TOPERATESWITHTHESUBJECTSEATEDORSUPINE ANDPROVIDESTIME SYNCHRO NIZEDDATACOMPATIBLEWITHOTHERCOMPLEMENTARYANALYSES4HEDATAOUTPUTCONSISTSOF WORKRATESINWATTS ANDPEDALSPEEDINRPM FORUSEWITHADATAACQUISITIONSYSTEM 4HECYCLEERGOMETERISUSEDASBOTHAEROBICANDANAEROBICEXERCISECOUNTERMEASURE FOR THE MAINTENANCE OF LOWER BODY MUSCULATURE ENDURANCE FOR %6! ARM EXERCISE TRAINING ANDAS%6! HOURPRE BREATHEEXERCISECOUNTERMEASURE 4HEI2%$THATʅEWONBOARDTHE)33UNTILWASLIMITEDINTHEMAXIMALLOADS THATITCOULDPROVIDE ANDTHUSWASVIEWEDASANINTERIMSOLUTIONTOTHELOSSOFMUSCU LARSTRENGTH)TWASREPLACEDBYANOTHERDEVICE THEA2%$ ASAMORELONG TERMSOLU TION4HEA2%$ISDESIGNEDTOPROVIDEGREATEREXERCISECAPABILITYTHANTHEI2%$FOR PRESERVING MUSCLE STRENGTH AND BONE STRENGTH AND ENDURANCE &IGURE   )T IS A

 *ON3TEWARTDEMANDEDHEBEHONOREDSIMILARLYBUTTURNEDDOWN.!3!ȀSOFFERTONAMETHE)335RINE 0ROCESSORȃ3PACE4OILET%NVIRONMENTAL7ASTE!CCUMULATOR2ECYCLING4HINGYȄ

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Figure 5.20. NASA Selected the Treadmill’s Name After Comedian and Host Stephen Colbert of Comedy Central’s “The Colbert Report” Took Interest During the Node 3 Naming Poll and Urged His Followers to Post the Name “Colbert,” Which Received the Most Entries. “I’ve Always Wanted To Be an Astronaut. […] I’ve Already Started at Home Getting Used to Weightlessness; I’ve Let My Muscles Atrophy for 46 Years,” Colbert Said. (Credit NASA).

Figure 5.21. The Advanced Resistive Exercise Device (aRED) Used on the ISS Enables Various Weightlifting Exercises. Unlike the Bowflex’s Rubber Bands, Which Were Used by the Machine Being Replaced (the iRED), the aRED Uses Piston-Driven Vacuum Cylinders That Provide Adjustable Resistance as the Piston Is Pulled in or out. A Flywheel System Counteracts the Force of the Pistons to Simulate the Response of Free Weights in Normal Gravity. (Credit NASA).

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VERSATILE MACHINE THAT CAN BE USED TO PERFORM THREE PRIMARY RESISTIVE EXERCISES FOR STIMULATINGBONEREGENERATIONANDEXERCISINGTHEMAJORMUSCLEGROUPS ASWELLAS OTHEREXERCISESFORSECONDARYMUSCLEGROUPS 4HEA2%$CONSISTSOFAPAIROFVACUUMCYLINDERS AFRAME AND PLATFORMASSEMBLY ANARMBASEASSEMBLY AWISHBONEARMLIFTBAR ACABLE AND PULLEYMECHANISM ANDA ʅYWHEEL MECHANISM 4HE ʅYWHEEL ASSEMBLY ROTATES AS THE ARM BASE ASSEMBLY IS MOVED THUSPROVIDINGANINERTIALLOADTHATSIMULATESTHELIFTINGOFWEIGHTSINNORMAL %ARTHȀSGRAVITY4HEA2%$CANBECONʄGUREDTOPROVIDEEXERCISESUSINGTHELIFTBAROR THEEXERCISECABLE4HELEVERISABLETOPROVIDELOADSRANGINGFROMTOKG5SING THECABLE THELOADSARELIMITEDTOAMAXIMUMOFKG !MAJORFEATUREOFA2%$ISTHEINSTRUMENTATIONSYSTEM)TINCLUDESTRIAXIALFORCE SENSORSTHATRECORDFORCEINTHREEDIMENSIONS,OADSENSORSINTHEMAINLIFTARMANDTHE ARM BASE ASSEMBLY MEASURE UNIDIRECTIONAL FORCES 4HE ARM BASE ASSEMBLY ALSO HAS ROTATIONALSENSORSTHATRECORDTHERANGEOFMOTIONOFTHEARM$URINGEXERCISE THELOAD ANDNUMBEROFREPETITIONSARESIMULTANEOUSLYRECORDEDANDDISPLAYEDONATABLET0# IN WHICHTHEINDIVIDUALLYCUSTOMIZEDCREWMEMBERPROʄLESARESTORED4HERECORDEDDATA CANBEDOWNLINKEDTOTHEGROUND ANDEXERCISEPRESCRIPTIONSCANBESENTFROMTHEGROUND TOTHEA2%$TABLET0#4HEEXERCISEPRESCRIPTIONISAUTOMATICALLYLOADEDINTOANINDI VIDUALCREWMEMBERPROʄLE%XERCISESPERFORMEDONTHEA2%$ARELISTEDIN4ABLE !NOTHERPIECEOFEXERCISEEQUIPMENTISTHE-USCLE!TROPHY2ESEARCHAND%XERCISE 3YSTEM-!2%3 FORRESEARCHONMUSCULO SKELETAL BIOMECHANICAL ANDNEUROMUSCU LAR HUMAN PHYSIOLOGY 4HE -!2%3 HARDWARE IS MADE UP OF AN ADJUSTABLE CHAIR A DIRECT DRIVE MOTOR A LINEAR ADAPTER THAT TRANSLATES MOTOR ROTATION INTO LINEAR MOVE MENTS ANDAVIBRATIONISOLATIONFRAME&IGURE )TWORKSASADYNAMOMETERTO MEASUREFORCEORTORQUEONSEVENDIFFERENTJOINTS-USCLECONTRACTIONCANBEISOMETRIC MUSCLECONTRACTIONATAʄXEDLENGTH IE NOMOVEMENT ISOTONICCONCENTRICMUSCLE SHORTENSASITCONTRACTSATACONSTANTTORQUE ISOKINETICCONCENTRICMUSCLESHORTENSAS Table 5.1.

Core and Auxiliary Exercises (Bar and Cable) Performed on the aRED. Typically, a 3-Day Cycle Per Week Is Used as Follows: Day 1: Low Load & High Reps; Day 2: Moderate Load & Moderate Reps; Day 3: High Load & Low Reps.

Core Exercises

Bar Exercises

Cable Exercises

Squat

Bench press

Anterior shoulder raise

Deadlift

Bent over row

Biceps curl

Heel raise

Biceps curl

Rear shoulder raise

Single-leg heel raise

Lunge

Hip abduction

Single-leg squat

Shoulder press

Hip adduction

Straight-leg deadlift

Shrugs

Hip flexion

Single-arm deadlift

Hip extension

Upright row

Lateral arm raise

Wrist curl

One-arm cable row Triceps extension Triceps pulldown

4HE-USCULO 3KELETAL3YSTEMIN3PACE



Figure 5.22. Photographs Showing the MARES Hardware Being Tested on the Ground (Left) and Recently Deployed in the Columbus Module of the ISS (Right). (Credit NASA).

ITCONTRACTSBUTATACONSTANTVELOCITY ORISOTONICANDISOKINETICECCENTRICMUSCLE EXTENDED  -!2%3 MAY BE USED TOGETHER WITH AN ASSOCIATED DEVICE CALLED THE 0ERCUTANEOUS%LECTRICAL-USCLE3TIMULATOR0%-3  !HAND HELDGRIPDYNAMOMETERHASALSOBEENDEVELOPEDTOMEASUREISOMETRICFORCE ANDSUSTAINEDSTATICEXERCISEOFTHETHUMBANDOPPOSINGʄNGERORGROUPINGSOFʄNGERS ONEACHHANDNOTINCLUDINGOPPOSINGHANDACTIVITY CONTINUOUSLYFORUPTOS4HIS DEVICEISUSEDTOTESTFOREARMMUSCLEFATIGUEBEFOREAN%6! !SPREVIOUSLYDISCUSSED 2USSIANCOSMONAUTSWEARTHEȃ0ENGUINȄSUITDURINGLONG DURATIONMISSIONSSEE&IGURE "ESIDEITSEFFECTONTHECARDIO VASCULARSYSTEM THE ELASTIC BANDS IN THE SUIT ALSO SIMULATE SOME OF THE GRAVITATIONAL EFFECTS ON THE MUSCULO SKELETALSYSTEM%XPANDERSORBUNGEECORDS&IGURE AREALSOUSEDOCCA SIONALLY(OWEVER THEYDONOTPROVIDESUFʄCIENTFORCEDURINGAXIALLOADINGFORBONE MAINTENANCE ANDPRESENTAREDUCEDRANGEOFMOTIONAGAINSTRESISTANCECOMPAREDTO THEINTERIMRESISTANCEEXERCISEDEVICEDESCRIBEDABOVE !MOREUNCONVENTIONALPOSSIBILITYISTHATASTRONAUTSCOULDSTAVEOFFMUSCLEATROPHY BYTAKINGAPILL(OWEVER ANTI ATROPHYPILLSAREONLYSPECULATIVERIGHTNOW BUTTHERE AREREASONSTOBELIEVETHATTHEYMIGHTBEPOSSIBLE4HATȀSBECAUSEWHENATROPHYSETS IN THEMUSCLEISNȀTJUSTWITHERINGAWAYPASSIVELY ITISACTIVELYBREAKINGITSELFDOWN
!STRONAUTSUSECOMMONPAINKILLERDRUGSFORDISCOMFORTDUETOBACKPAINORSOREMUS CLES AND . !CETYL #YSTEINE AND OTHER SUPPLEMENTSPHARMACOLOGICS FOR MUSCULAR STRENGTHANDENDURANCEPRESERVATION)THASBEENSUGGESTEDTHATPROTEINSYNTHESISRATES BEINCREASEDWITHSUPPLEMENTSOFAMINOACIDS WHICHARETHERAWMATERIALSOFPROTEIN )NDEED EARLYRESULTSDURINGBEDRESTSTUDIESHAVESUGGESTEDTHATTHEAMINOACIDSUP PLEMENT WAS ABLE TO MAINTAIN SYNTHESIS RATES AND BODY MASS !LSO STUDIES IN RATS INDICATEDTHATMUSCLESPRODUCEAHORMONE CALLEDINSULIN LIKEGROWTHFACTOR)'&  INRESPONSETOSTRENUOUSEXERCISE ANDTHISHORMONEINTURNACTIVATESENZYMESINTHE

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Figure 5.23. Left: Bungee Cords Used for Exercising While Free-Floating on Board the ISS. (Credit NASA). Right: The MIT Skinsuit Creates a Loading Regime that Reproduces the Bone and Muscle Weight-Bearing Regime on Earth [Waldie and Newman, 2010].

MUSCLECELLSTHATCAUSETHECELLSTOGROWJUSTAFTEREXERCISING)TISPOSSIBLETHATITIS THEMECHANICALSTRESSTHATTURNSONTHEGENEFOR)'&  BUTWEREALLYDONȀTUNDERSTAND THATPROCESSYET-IGHTSUPPLEMENTSOF)'& BEUSEDTOENSURETHATCONSTRUCTIONOF MUSCLE PROTEINS KEEPS PACE WITH PROTEIN DESTRUCTION IN ASTRONAUTS 3CIENTISTS ARE ENTERTAININGTHEIDEAANDAREALREADYDISCUSSINGWAYSINWHICHTHATMIGHTBEDONE ;.!3! = 

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!VARIETYOFSTUDIESAREBEINGCONDUCTEDONTHEBASICMECHANISMSOFTHEEFFECTSOF MECHANICALFORCESONBONEDYNAMICSANDDEVELOPMENT3UCHSTUDIESMAYGIVEINSIGHT FORCOUNTERMEASURESBASEDONEXERCISE DRUGS ORDIET  %XERCISE %VIDENCEFROMBEDRESTSTUDIESANDSPACEʅIGHTSUGGESTSTHATBONELOSSISAREGIONAL PHENOMENONINWHICHTHEBONEAREASWITHTHEGREATESTDECREASEINLOADLOSETHEMOST BONE;/GANOVETAL ,E"LANCETAL =3KYLABASTRONAUTSAVERAGEDPER MONTHTOTALBODYCALCIUMLOSSDESPITEEXERCISINGANUMBEROFHOURSADAYTHROUGHA SERIESOFEXERCISESCONSISTINGOFBUNGEECORDSFORRESISTIVEEXERCISES CYCLEERGOMETER EXERCISE AND WALKING ON A TREADMILL ;4HORNTON AND 2UMMEL = %XERCISE SCHEDULESTYPICALLYREQUIREDHOFEXERCISEDAILY(OWEVER COSMONAUTSCONTINUETO LOSEBONESELECTIVELYFROMTHESPINEANDLOWEREXTREMITIESWHILEMAINTAININGUPPER BODYBONEMINERALDENSITY;/GANOVETAL = 4HEHUMANBODYISDESIGNEDTOBEARWEIGHT7ITHOUTTHESTIMULATIONTHATISCAUSED BYPLACINGWEIGHTONLOWEREXTREMITIES WHETHERDUETOTHEMICROGRAVITYENVIRONMENT ORLACKOFUSEON%ARTH BONESLOSEMASSANDMUSCLESLOSESTRENGTH!NEXPERIMENT RECENTLY CHARACTERIZED THE LOAD THAT IS PLACED ON LOWER EXTREMITIES DURING DAILY ACTIVITIESONTHE)33ANDEXAMINEDTOWHATDEGREEMECHANICALLOADSTIMULUS VIAAN

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IN ʅIGHT EXERCISE ROUTINE COULD PREVENT THE MUSCLE ATROPHY AND BONE LOSS THAT IS ASSOCIATEDWITHSPACEʅIGHT 4HEAMOUNTOFFORCETHATISPLACEDONTHEBOTTOMOFTHEFOOT ASWELLASJOINTANGLES ATTHEANKLE KNEE ANDHIPWEREMEASURED%LECTROMYOGRAPHYELECTRODESRECORDEDLEG ANDARMMUSCLEACTIVITY+NEE JOINTMOTIONINSPACEWASREDUCEDWHENCOMPAREDTO THATON%ARTH THUSEFFECTINGMUSCLEACTION-EASUREMENTSOFFORCESDURINGEXERCISE SUGGESTED THAT MUCH LESS FORCE WAS EXPERIENCED THAN WOULD BE EXPERIENCED WHEN EXERCISINGON%ARTH"ASEDONTHESEDATA #AVANAUGHAND2ICE;=HAVECOMPILED ASETOFSUMMARYARTICLESTHATEXAMINESBONEHEALTH BONELOSS EFʄCACYOFEXERCISE ANDMECHANICALSTIMULUS ANDOTHERFACTORSTHATARERELEVANTTOBONEHEALTHINSPACE  -ECHANICALCOUNTERMEASURES !LL OF THE MECHANICAL PROCEDURES TESTED THUS FAR DURING BED REST STUDIES HAVE BEEN INEFFECTIVE #ORRELATIVE OBSERVATIONS HAVE INDICATED THAT THE REQUIRED PROCEDURE FOR USEIN ʅIGHTSHOULDPROVIDETHEEQUIVALENTFORCEONTHESKELETONOFHOFWALKING PERDAY 3OMESCIENTISTSCURRENTLYBELIEVETHATBONEMASSISNOTONLYCONTROLLEDBYTHEHIGH MAGNITUDE LOW FREQUENCYSTRAINRESULTINGFROMTHEMECHANICALLOADSONBONESASSOCIATED WITHVIGOROUSEXERCISE BUTALSOBYLOW MAGNITUDEANDHIGH FREQUENCYSTRAINTHATMUSCU LATURE CONTINUOUSLY PLACES ON BONES WHILE SITTING OR STANDING )T IS WELL KNOWN THAT MECHANICALLOADSSTRESS CAUSESSLIGHTDEFORMATIONSCALLEDSTRAIN4HEAMOUNTOFSTRAINIS DEPENDENTONLOADING ELASTICITY ANDGEOMETRYOFTHEBONE!NUPPERLIMITSTRAINMUSTBE EXCEEDEDTOPROVOKEREMODELINGTOINCREASEBONEMASS-ECHANICALSTRAINBELOWALOWER LIMITWILLPROVOKEADAPTIVEREMODELINGTOREDUCEMASS 2ESULTS OF GROUND BASED STUDIES SUGGEST THAT BARELY PERCEPTIBLE VIBRATIONS MAY GENERATE ENOUGH STRAIN TO STIMULATE BONE GROWTH &OR EXAMPLE A GROUP OF SHEEP EXPOSED TO  MIN PER DAY OF VIBRATIONS EXPERIENCED INCREASED TRABECULAR BONE FORMATIONWHENCOMPAREDTOACONTROLGROUPTHATWASNOTEXPOSEDTOVIBRATIONS;2UBIN ET AL = &IGURE   )N ADDITION WHEN ANIMALS THAT WERE PREVENTED FROM

Figure 5.24. After a Year of Daily 20 min Standing on a Vibrating Platform (0.3 g, 30 Hz), Sheep Showed the Robust Striations of Increased Density (Right). Control Sheep Showed Normal Bone (Left) [Rubin et al., 2002].



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R EGULAR WEIGHT BEARING ACTIVITY WERE EXPOSED TO VIBRATIONS DAILY BONE FORMATION REMAINEDATNEAR NORMALLEVELS(OWEVER ANIMALSNOTEXPOSEDTOTHETREATMENT BUT PARTICIPATINGINWEIGHT BEARINGACTIVITYEACHDAY STILLEXHIBITEDSIGNSOFSIGNIʄCANT BONELOSS)FPROVENVALUABLEFORHUMANS LOW LEVELVIBRATIONSDURINGSPACEʅIGHTMAY OFFER AN ALTERNATIVE FOR THE CURRENT TIME CONSUMING ASTRONAUT EXERCISE REGIMES FOR LONG DURATIONSPACEMISSIONS  .UTRITIONALCOUNTERMEASURES )NADDITIONTOCALORICINTAKE PROTEIN CALCIUM ANDOTHERNUTRIENTSTHATAREASSOCIATED WITH BONE METABOLISM INCLUDING PHOSPHORUS SODIUM POTASSIUM AND MAGNESIUM HAVE NO LIMITS OR REQUIREMENTS THAT ARE SPECIʄC FOR THE MICROGRAVITY ENVIRONMENT .UTRITIONALRECOMMENDATIONSFORSPACEʅIGHTARENODIFFERENTFROMTHERECOMMENDA TIONSOFTHE.ATIONAL2ESEARCH#OUNCILFORLIFEON%ARTH;-C#ORMICK = !REASONABLEBASEʄGUREFORDAILYCALCIUMINTAKEINDIETFORMULATIONFORSPACEʅIGHT IS MG4HEPRINCIPALPURPOSEOFDAILYCALCIUMSUPPLEMENTATIONISFORȃPROTECT INGȄ THE SKELETON !MONG THE COUNTERMEASURES TESTED HAVE BEEN HIGH CALCIUM AND HIGHPHOSPHORUSINTAKEINBOTHBEDRESTSUBJECTSAND3KYLABAND-IRASTRONAUTS4HE STUDY SHOWED THAT THIS PROCEDURE MAINTAINED CALCIUM INTAKE AND EXCRETION LEVEL IN BALANCEFORUPTOMONTHS FOLLOWINGWHICHTHEGRADUALLYRISINGFECALEXCRETIONOF CALCIUMCAUSEDANEGATIVECALCIUMBALANCE(ENCE THEREISNOBASISATTHISTIMEFOR RECOMMENDINGAHIGHERINTAKELEVELTHAN MGDAY "ED REST STUDIES ADDRESSING THE EFFECTS OF HIGH PHOSPHORUS INTAKE SHOWED SOME SUPPRESSIONOFTHETENDENCYOFURINARYCALCIUMTOELEVATE BUTTHEMANIPULATIONWAS INEFFECTIVEBECAUSEOFGRADUALLYINCREASINGFECALCALCIUMEXCRETION&URTHERMORE THE CALCIUMTOPHOSPHORUSRATIOSHOULDNOTEXCEEDARATIOOF)NDEED TOOHIGHAN INTAKEOFPHOSPHORUSWILLEXERTSOMEBINDINGEFFECTONCALCIUMINTHEINTESTINEAND TENDTOINHIBITCALCIUMABSORPTION 4HE CURRENT RECOMMENDED LEVEL FOR MAGNESIUM IS  MGDAY FOR ADULT MALES 7HILESTUDIESOFTHISELEMENTINRELATIONTOBONEAREFARLESSNUMEROUSTHANSTUDIESOF CALCIUM RESEARCH TO DATE INDICATES THAT DELETERIOUS EFFECTS APPARENTLY DO NOT OCCUR EXCEPTPOSSIBLYWITHLOWINTAKE ASINANARTIʄCIALDIET OVERAVERYLONGTIME#ERTAIN BISPHOSPHONATECOMPOUNDSTHATBINDTOBONECRYSTALANDTENDTOINHIBITBONERESORP TIONSHOWPROMISE4HESECOUNTERMEASURESTUDIESCONTINUE  0HARMACOLOGICALCOUNTERMEASURES "IOCHEMICALREGIMENSHAVEBEENSTUDIEDDURINGBEDRESTA SYNTHETICSALMONCALCI TONIN AHORMONEINHIBITINGBONERESORPTIONB PHOSPHATESUPPLEMENTSC ORALCAL CIUMANDD ETIDRONATE!LLSHOWEDNOBENEʄCIALEFFECT;&LEISCHETAL (ULLEY ETAL =(OWEVER DURINGTHELASTWEEKSOFBEDREST THEUSUALPROGRESSIONOF CALCANEALMINERALLOSSWASNOLONGEROBSERVED%TIDRONATE HOWEVER HASBEENASSOCI ATEDWITHANACCUMULATIONOFNEWBONETISSUEBOTHINANIMALSANDMANWHENGIVENAT HIGHDOSEFOREXTENDEDPERIODSOFTIME;-EUNIERETAL = .EWBISPHOSPHONATESAREBEINGTESTEDFORTREATINGGLOBALBONELOSSDISEASESSUCH ASPOST MENOPAUSALOSTEOPOROSIS&OREXAMPLE ALENDRONATEWASEFFECTIVEINPREVENT INGHYPERCALCIURIAANDMAINTAININGBONEMINERALDENSITYINTHEFEMORALNECK FEMORAL TROCHANTER SPINE ANDPELVISINHUMANSDURINGBEDRESTSTUDIES-ODERATELOSSOFBONE

4HE-USCULO 3KELETAL3YSTEMIN3PACE



MASSDENSITYOCCURREDINTHECALCANEUS BUTTHELOSSWASSIGNIʄCANTLYLESSTHANINTHE CONTROLGROUP;2UMLETAL =!NEXPERIMENTUSINGBISPHOPHONATESONTHECREW MEMBERSOF)33HASBEENONGOINGSINCE%XPEDITION "ISPHOSPHONATESHELPREDUCE BONELOSSBYBLOCKINGBREAKDOWNOFBONE4HISSTUDYTESTSTHEEFFECTIVENESSOFTWO BISPHOSPHONATESALENDRONATE TAKENASAPILLONCEPERWEEKBEFOREANDDURINGSPACE ʅIGHT ANDZOLEDRONICACID GIVENBYINTRAVENOUSINFUSIONONCEBEFOREʅIGHTWITHAN EFFECTLASTINGFORTHELENGTHOFTHEʅIGHT;,E"LANCETAL = !NOTHERPOSSIBLEPHARMACOLOGICALCOUNTERMEASUREISPARATHYROIDHORMONE04(  04(ISTHEMOSTIMPORTANTENDOCRINEREGULATOROFCALCIUMANDPHOSPHORUSCONCENTRA TIONINEXTRACELLULARʅUID3ECRETEDFROMCELLSOFTHEPARATHYROIDGLAND THISHORMONE ʄNDSITSMAJORTARGETCELLSINBONESANDTHEKIDNEYS04(STIMULATESOSTEOCLASTSTO REABSORB BONE MINERAL )N ADDITION TO STIMULATING ʅUXES OF CALCIUM INTO THE BLOOD FROMBONESANDTHEINTESTINES 04(SLOWSTHEEXCRETIONOFCALCIUMINURINE THUSCON SERVINGCALCIUMINBLOOD /THERSTUDIESARELOOKINGATTHEHORMONEGLUCOSE DEPENDENTINSULINOTROPICPEPTIDE THATISINVOLVEDININSULINPRODUCTIONFORWHICHSOMEBONECELLSHAVERECEPTORS4HESE STUDIESAIMTOASCERTAINWHETHERTHELOSSOFBONEINSPACECANBEPREVENTEDBYMODULAT INGAPERSONȀSOWNPRODUCTIONOFTHEHORMONEORBYGIVINGITBYINJECTIONORTABLET -ICE THAT WERE EXPOSED TO MICROGRAVITY ON BOARD THE )33 EXHIBITED A ǻ DECLINE IN FEMUR ELASTIC STRENGTH AND A ǻ DECREASE IN BONE FORMATION WHEN COMPARED TO THE CONTROLS 4HE FEMUR ELASTIC STRENGTH DECLINE WAS CAUSED BY THREE MECHANISMS REDUCED BONE FORMATION INCREASED BONE RESORPTION AND INHIBITION OF MINERALIZATION -ICE THAT WERE TREATED WITH OSTEOPROTOGERIN /0' BEFORE BEING EXPOSEDTOMICROGRAVITY EXHIBITEDNODISCERNABLEDECLINEINFEMURELASTICSTRENGTH ANDBONERESORPTIONWASSIGNIʄCANTLYINCREASED;"ATEMANETAL =/0'ISABONE METABOLISMREGULATORTHATISEVALUATEDBYTHE53&EDERAL$RUG!DMINISTRATIONASA NEWTREATMENTFOROSTEOPOROSIS-ECHANICALTESTINGDATAWERECOMPLIMENTEDBYSERUM M2.! ANDHISTOLOGICALANALYSESTHATINDICATEDADECLINEINBONEFORMATIONANDAN INCREASEINBONERESORPTIONINADDITIONTOANINHIBITIONOFMINERALIZATION/0'MITI GATED THE DECLINE IN MECHANICAL STRENGTH BY PREVENTING INCREASE IN RESORPTION AND MAINTAININGMINERALIZATION;(ARRISONETAL = &URTHERSTUDIESAREALSONEEDEDTOCLARIFYTHERELATIONSHIPSAMONGTHEDIFFERENTSYS TEMS IE MUSCULO SKELETAL NUTRITIONAL CARDIO VASCULAR ANDNEURO VESTIBULAR)NDEED ITWASRECENTLYSHOWNTHATTHESYMPATHETICNERVOUSSYSTEMREGULATESBONEREMODELING .ERVEʄBERSHAVEBEENDETECTEDINBONEINCLOSEVICINITYTOTHEOSTEOBLASTS"ECAUSE THESYMPATHETICNERVOUSSYSTEMCONTROLSBONEREMODELINGANDTHEVESTIBULARSYSTEM INʅUENCES THE SYMPATHETIC NERVOUS SYSTEM THE VESTIBULAR SYSTEM COULD WELL BE INVOLVEDINBONEREMODELING;$ENISEETAL =)NFACT ANIMALRESEARCHINDICATES THATTHEBONELOSSINDUCEDBYBILATERALVESTIBULARLESIONHASTHESAMEDISTRIBUTIONASTHE BONE LOSS INDUCED BY SPACEʅIGHT 4HE SYMPATHETIC NERVOUS SYSTEM COULD POSSIBLY MODIFYBONEMETABOLISMDIRECTLYVIAOSTEOCLASTICANDOSTEOBLASTICE ADRENERGICRECEP TORS OR INDIRECTLY VIA MODIʄCATIONS OF THE VASCULARISATION OR BOTH #ONSEQUENTLY E BLOCKERSSUCHASPROPRANOLOLAREPOTENTIALCOUNTERMEASURESINPREVENTINGBONELOSS /N%ARTH ANEPIDEMIOLOGICSTUDYDEMONSTRATEDTHATTHEUSEOFE BLOCKERSISASSOCI ATED WITH REDUCED RISK OF FRACTURES ;3CHLIENGER ET AL = 4HESE NEW AREAS OF RESEARCH INDICATES THAT A GREATER EFFORT TOWARD A COORDINATED MULTIDIMENSIONAL

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APPROACH WITHANULTIMATEGOALOFPREVENTIONANDREHABILITATION ISREQUIREDINORDER TODESIGNSTRATEGIESTOCOUNTERACTTHEEFFECTSORTREATASNEEDED RESEARCHTHATWILLALSO BENEʄTTOOSTEOPOROSISPATIENTSON%ARTH 

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4HEREISANEEDFORDEVELOPINGAPRACTICAL INEXPENSIVE NON INVASIVEWAYOFMAKING MUSCLEANDBONEMASSANDSTRENGTHMEASUREMENTS ASYSTEMSENSITIVEENOUGHTOMON ITORANDEVALUATESMALLCHANGES4HENEEDFORSUCHANINSTRUMENTGOESWAYBEYOND SPACEʅIGHT3INCEMUSCLEANDBONEABNORMALITIESAFFECTASUBSTANTIALPORTIONOFTHE POPULATION SUCHANINSTRUMENTWOULDOFFERBROADUTILITYASATOOLFORCLINICIANSON %ARTH&OREXAMPLE THEINFORMATIONGAINEDFROMTHISINSTRUMENTMAYBENEʄTTHEPEO PLEHEREON%ARTHWHOSEDAILYACTIVITIESAREAFFECTEDBYMETABOLICDEʄCIENCIES WEAK ENEDMUSCLES ORLOSSOFBONEMASS3OMEMETABOLICDISEASES FOREXAMPLE RESULTIN DEBILITATINGMUSCULARWEAKNESS ACONDITIONTHATCOULDBEIMPROVEDBYADVANCESIN PROTEIN TURNOVER RESEARCH ,IKEWISE MUSCLE WASTING IS PROBLEMATIC FOR SENIOR CITI ZENS PATIENTS CONʄNED TO LENGTHY BED REST PATIENTS WITH SPINAL NERVE DAMAGE AND EVENBURNVICTIMSRECOVERINGFROMTRAUMATICACCIDENTS /LDERPEOPLEALSOCOMMONLYEXPERIENCEALOSSOFBONEMASS ACONDITIONOFTENDUE TOTHEAGE RELATEDDISEASEOSTEOPOROSIS"ONELOSSINSPACEISNOTIDENTICALTOOSTEOPO ROSISON%ARTH BECAUSETHEREISACLEARHORMONALCOMPONENTINOSTEOPOROSIS!SWE AGE WEALSOLOSEMUSCLEMASSANDSTRENGTH APHENOMENONCALLEDSARCOPENIA4HIS CONTINUOUSREDUCTIONOFMUSCLESTRENGTHISLARGESTINTHEANTIGRAVITYMUSCLES!GING EFFECTSDIFFERFROMSPACEʅIGHTINTHATA THEENTIREBODYISINVOLVEDB MUSCLELOSS INTHEAGINGHASNOPLATEAUANDC ISCHARACTERIZEDBYFASTTWITCH4YPE)) TOSLOW TWITCH4YPE) ʄBERTRANSFORMATION;2ITTWEGERETAL =4HEREISALSOAREDUCTION INTHENUMBEROFMUSCLEʄBERSANDCROSS SECTIONALAREA!NIMBALANCEINTHENATURAL CYCLEOFPROTEINTURNOVERMAYBEACONTRIBUTINGFACTORTODECREASEDMUSCLEMASS $OESSPACEʅIGHTPUSHTHEASTRONAUTSALONGTHEIRREVERSIBLEAXISOFAGING7HENHE ʅEWONTHESPACESHUTTLEATTHEAGEOF *OHN'LENNWASTHESUBJECTFORAMUSCLELOSS EXPERIMENT WHOSEAIMWASTOINVESTIGATEWHETHERORHOWWEIGHTLESSNESSCANAFFECT THEELDERLYMORETHANYOUNGERASTRONAUTS&IGURE 3AMPLESOFBLOODANDURINE WERECOLLECTEDDURINGTHEʅIGHTAFTER'LENNSWALLOWEDPILLSCONTAININGAMINOACID . ALAMINE4HESTUDYCOMPAREDTHEAMOUNTOFAMINOACIDSABSORBEDINTOTHEBODY TOTHEAMOUNTPASSINGOUTINURINE ANDCALCULATEDHOWQUICKLYPROTEINSAREBUILTUP ANDBROKENDOWN4HEHYPOTHESISWASTHATGIVENTHESIMILARITIESBETWEENAGINGAND SPACEʅIGHT PERHAPSANOLDERPERSONMIGHTBEEVENBETTERPREPAREDTHANAYOUNGERONE FORTHEPHYSICALCHANGESBROUGHTONBYSPACEʅIGHT/LDERINDIVIDUALSMIGHTTHEREFORE EXPERIENCEFEWERCHANGESINSPACE4HISDIDNOTTURNOUTTOBETHECASEFORTHISPARTICU LARINDIVIDUAL'LENNȀSMUSCLELOSSLOOKEDABOUTTHESAMEASTHATOFOTHERYOUNGER SUBJECTSEXPOSEDTOTHESAMETESTS!LSO HISCARDIO VASCULARANDMUSCLESTRENGTHDATA LOOKED LIKE ANY OTHER HEALTHY MIDDLE AGED ASTRONAUT (OWEVER HIS MUSCLE VOLUME ANDSOMEIMMUNEDATALOOKEDMORELIKEHEHADBEENINSPACEWEEKSINSTEADOFONE 4HISMIGHTMERELYBEAFUNCTIONOFHISAGE4HEGOODNEWSISTHATTHESERESULTSINDI CATETHATANOLDERPERSONINGOODHEALTH AS'LENNWAS CANENDURETHECONDITIONSOF SPACEʅIGHT

4HE-USCULO 3KELETAL3YSTEMIN3PACE



Figure 5.25. U.S. Senator John H. Glenn Works Out on the Ergometer Device Onboard Space Shuttle Discovery During the STS-95 Mission in 1998. (Credit NASA).

"UTTHEANSWERISNOTSOSIMPLE BECAUSEAGINGISALSOASSOCIATEDWITHCHANGESIN HORMONES ACTIVITYLEVELS NUTRITION ANDOFTEN DISEASE.EVERTHELESS BYEXPLORINGTHE INTERACTION OF AGING AND SPACEʅIGHT RESEARCH WILL UNDOUBTEDLY CONTRIBUTE TO OUR KNOWLEDGEOFTHEAGINGPROCESS!BETTERUNDERSTANDINGOFBONEANDMUSCLECHANGES IN SPACEʅIGHT WILL ALSO LEAD TO TREATMENTS FOR ASTRONAUTS AND %ARTH BOUND PATIENTS ALIKE

2EFERENCES !RNAUD3" (ARPER*3 .AVIDI- -INERALDISTRIBUTIONINRATSKELETONSAFTER EXPOSURE TO A MICROGRAVITY MODEL *OURNAL OF 'RAVITATIONAL 0HYSIOLOGY  ǻ "ALDWIN+-ETAL -USCULOSKELETALADAPTATIONSTOWEIGHTLESSNESSANDDEVEL OPMENT OF EFFECTIVE COUNTERMEASURES -EDICINE AND 3CIENCE IN 3PORTS AND %XERCISEǻ "ALLARD27 #ONNOLLY*0 535332JOINTRESEARCHINSPACEBIOLOGYANDMEDI CINEON#OSMOSBIOSATELLITES&!3%"*OURNALǻ "ATEMAN4! -ORONY3 &ERGUSON6, ETAL -OLECULARTHERAPIESFORDISUSE OSTEOPOROSIS'RAVITATIONALAND3PACE"IOLOGY"ULLETINǻ #APETANAKI9 -ILNER$* 7EITZER' $ESMININMUSCLEFORMATIONANDMAINTE NANCE+NOCKOUSANDCONSEQUENCES#ELL3TRUCTUREAND&UNCTIONǻ #AVANAUGH 02 2ICE !*  "ONE ,OSS $URING 3PACE &LIGHT %TIOLOGY #OUNTERMEASURES AND)MPLICATIONSFOR"ONE(EALTHON%ARTH#LEVELAND /( #LEVELAND#LINIC0RESS



&UNDAMENTALSOF3PACE-EDICINE

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4HE-USCULO 3KELETAL3YSTEMIN3PACE



-C#ORMICK $ONALD "  .UTRITIONAL RECOMMENDATIONS FOR 3PACEʅIGHT )N .UTRITION IN 3PACEʅIGHT AND 7EIGHTLESSNESS -ODELS ,ANE (7 3CHOELLER $! EDS "OCA2ATON &LORIDA#2#0RESS PPǻ -EUNIER9 #HAPUY-# $ELMAS0 )NTRAVENOUSDISODIUMETIDRONATETHERAPYIN 0AGETȀSDISEASEOFBONEANDHYPERCALCEMIAOFMALIGNANCY!MERICAN*OURNALOF -EDICINE3ǻ3 -OREY (OLTON%2 'LOBUS2+ (INDLIMB UNLOADINGOFGROWINGRATSAMODEL FORPREDICTINGSKELETALCHANGESDURINGSPACEʅIGHT"ONEǻ .!3! 7HY$O7ORKOUTS7ORK;ONLINE=!VAILABLEATHTTPSCIENCENASAGOV SCIENCE NEWSSCIENCE AT NASADEC?MUSCLES;!CCESSED/CTOBER= .ICOGOSSIAN!% 0ARKER*& 3PACE0HYSIOLOGYAND-EDICINE7ASHINGTON $# 53'OVERNMENT0RINTING/FʄCE .!3!30  /GANOV63ETAL "ONEMINERALDENSITYINCOSMONAUTSAFTERǻMONTHLONG ʅIGHTSABOARD/RBITAL3TATION-IR!EROSPACEAND%NVIRONMENTAL-EDICINEǻ 0ICQUET& &ALEMPIN- #OMPAREDEFFECTSOFHINDLIMBUNLOADINGVERSUSTER RESTRIAL DEAFFERENTATION ON MUSCULAR PROPERTIES OF THE RAT SOLEUS %XPERIMENTAL .EUROLOGYǻ 2ILEY$!ETAL 3KELETALMUSCLEʄBER NERVE ANDBLOODVESSELBREAKDOWNIN SPACE ʅOWNRATS&!3%"*OURNALǻ 2ILEY$!ETAL )N ʅIGHTANDPOSTʅIGHTCHANGESINSKELETALMUSCLESOF3,3  AND3,3 SPACEʅOWNRATS*OURNALOF!PPLIED0HYSIOLOGYǻ 2ITTWEGER* 'UNGA(# &ELSENBERG$ +IRSCH+! -USCLEANDBONEǼ!GING ANDSPACE*OURNALOF'RAVITATIONAL0HYSIOLOGYǻ 2UBIN# 4URNER3 "AIN3 -ALLINCKRODT# -C,EOD+ %XTREMELYLOWLEVEL MECHANICALSIGNALSAREANABOLICTOTRABECULARBONE.ATUREǻ 2UBIN# 4URNER!3 -ALLINCKRODT# *EROME# -C,EOD+ "AIN3 -ECHANICAL STRAIN INDUCEDNONINVASIVELYINTHEHIGH FREQUENCYDOMAIN ISANABOLICTOCAN CELLOUSBONE BUTNOTCORTICALBONE"ONEǻ 2UML,! $UBOIS3+ 2OBERTS-, 0AK#9# 0REVENTIONOFHYPERCALCIURIA ANDSTONE FORMINGPROPENSITYDURINGPROLONGEDBEDRESTBYALENDRONATE*OURNAL OF"ONEAND-INERAL2ESEARCHǻ 3CHLIENGER2' +RAENZLIN-% *ICK33ETAL 5SEOFBETA BLOCKERSANDRISKOF FRACTURES*AMAǻ 3IBONGA*$ %VANS(* 3UNG(' ETAL 2ECOVERYOFSPACEʅIGHT INDUCEDBONE LOSS"ONEMINERALDENSITYAFTERLONG DURATIONMISSIONSASʄTTEDWITHANEXPONEN TIALFUNCTION"ONEǻ 3TEIN 40 ,ESKIW -* 3CHLUTER -$  $IET AND NITROGEN METABOLISM DURING SPACEʅIGHTONTHE3HUTTLE*OURNALOF!PPLIED0HYSIOLOGYǻ 4HORNTON7% 2UMMEL*! -USCULARDECONDITIONINGANDITSPREVENTIONINSPACE ʅIGHT)N*OHNSTON2& $IETLEIN,&EDS "IOMEDICAL2ESULTSFROM3KYLAB7ASHINGTON $#53'OVERNMENT0RINTING/FʄCE .!3!30  #HAPTER PPǻ 4IPTON #-  !NIMAL MODELS AND THEIR IMPORTANCE TO HUMAN PHYSIOLOGICAL RESPONSES IN MICROGRAVITY -EDICINE AND 3CIENCE IN 3PORTS AND %XERCISE  3ǻ3 4ISCHLER -% ET AL  3PACEʅIGHT ON 343  AND %ARTH BASED UNWEIGHTING PRODUCE SIMILAR EFFECTS ON SKELETAL MUSCLE OF YOUNG RATS *OURNAL OF !PPLIED 0HYSIOLOGYǻ



&UNDAMENTALSOF3PACE-EDICINE

4ITZE*ETAL ,ONG TERMSODIUMBALANCEINHUMANSINATERRESTRIALSPACESTATION SIMULATIONSTUDY!MERICAN*OURNALOF+IDNEY$ISEASESǻ 6ICO , .OVIKOV 6% 6ERY *- !LEXANDRE #  "ONE HISTOMORPHOMETRIC COMPARISON OF RAT TIBIAL METAPHYSIS AFTER  DAY HINDLIMB UNLOADING VS  DAY SPACEʅIGHT!VIATION 3PACE%NVIRONMENTAL-EDICINEǻ 6ICO,ETAL %FFECTSOFLONG TERMMICROGRAVITYEXPOSUREONCANCELLOUSAND CORTICALWEIGHT BEARINGBONESOFCOSMONAUTS,ANCETǻ 7ALDIE *- .EWMAN $*  ! GRAVITY LOADING COUNTERMEASURE SKINSUIT !CTA !STRONAUTICA$OIJACTAASTRO 7ALTON+ 0OSTNATALDEVELOPMENTUNDERCONDITIONSOFSIMULATEDWEIGHTLESSNESS ANDSPACEʅIGHT"RAIN2ESEARCH2EVIEWSǻ

#HAPTER 0SYCHOLOGICAL)SSUESOF3PACEʅIGHT

4HISCHAPTEREMPHASIZESTHEIMPORTANCEOFMENTALANDSOCIALWELLBEINGINTHESUCCESS OFBOTHSHORTANDLONGSPACEMISSIONS7HATARETHEPSYCHOLOGICALANDSOCIOLOGICAL ISSUES WHICHMUSTBEADDRESSED ESPECIALLYFORINTERNATIONALMISSIONS4HISSECTION REVIEWSTHEFACTORSTHATMAYHAVEACRITICALIMPACTONTHESUCCESSORFAILUREOFASPACE MISSION INTERMSOFINTERACTIONSOFTHECREWMEMBERWITHHISHABITAT WITHTHESPACE ENVIRONMENT ANDWITHTHEOTHERCREWMEMBERS&IGURE 

 4HEPROBLEMREACTIONTOSTRESS !CCORDINGTOTHEMEDIA THE2USSIAN3PACE!GENCYONCELAUNCHEDARESCUEMISSIONTO THE-IRSPACESTATION!MONGTHREEMENABOARDTHECAPSULE ONEREPLACEDONECOSMONAUT INTHETWO PERSON-IRSPACESTATION ANDTHEOTHERSESCORTEDHIMBACKTO-OSCOW7HILE CARDIO VASCULARPROBLEMSWERETHEOFʄCIALREASONFORTHE-IRCOSMONAUTEARLYHOME COMING SOME53SPACEEXPERTSSAYTHEREMIGHTHAVEBEENADDITIONALDIFʄCULTIESFROM THESTRESSOFPROLONGEDWEIGHTLESSNESS ISOLATION ANDCONʄNEMENT;"URROUGH = 4HIS EXAMPLE ILLUSTRATES THE PROBLEM WITH PSYCHOLOGICAL ISSUES DURING SPACE MISSIONSALTHOUGHTHEYPRESUMABLYEXIST MOSTOFTHEREPORTSAREANECDOTAL)NFACT PSYCHIATRICPROBLEMSDURINGSPACEMISSIONS SUCHASANXIETY DEPRESSION PSYCHOSIS PSYCHOSOMATICSYMPTOMS ANDPOSTʅIGHTPERSONALITYCHANGES HAVEBEENRAREORNOT METHODICALLY DOCUMENTED +NOWN NEGATIVE PSYCHOLOGICAL REACTIONS TO SPACEʅIGHT HAVE INCLUDED SLEEP PROBLEMS REDUCED ENERGY LEVELS MOOD AND THOUGHT DISORDERS ALTERATIONINTIMESENSE ANDPOORINTERPERSONALRELATIONS)NTERPERSONALISSUESINCLUDE INTERPERSONALTENSION DECREASEDCOHESIVENESSOVERTIME NEEDFORPRIVACY ANDTASK VERSUS EMOTIONAL LEADERSHIP ;+ANAS AND -ANZEY = .ONE OF THESE PROBLEMS HOWEVER SEEMSTOHAVESERIOUSLYAFFECTEDASPACEMISSIONYET PROBABLYDUETOTHE EXTRAORDINARY MOTIVATION AND COMMITMENT OF THE ASTRONAUTS (OWEVER $R 0ATRICIA 3ANTY APSYCHIATRISTANDʅIGHTSURGEONWHOWORKEDAT.!3! ANDAUTHOROFTHEBOOK #HOOSINGTHE2IGHT3TUFF;3ANTY = SAIDTHATEVENHIGHLYMOTIVATEDPEOPLEHAVEA LIMIT3HESETSTHATLIMITATORWEEKSȃ!FTERTHAT IFYOUHAVEINTERPERSONALCONʅICT INTHATCONʄNEDMICROSOCIETY THINGSCANGETOUTOFHANDȄ 3PACE TRAVEL REQUIRES ESTABLISHING AND MAINTAINING EFFECTIVE STABLE INTERACTIONS BETWEENINDIVIDUALSINSMALLGROUPSTHATAREUNDERMICROGRAVITYCONDITIONSANDARE ISOLATEDANDCONʄNEDFORPROLONGEDPERIODS)NDIVIDUALBEHAVIORADJUSTMENT INTERPER SONAL CONʅICT AND GROUP PERFORMANCE EFFECTIVENESS ARE TYPICALLY EXACERBATED IN ISOLATED AND CONʄNED GROUPS 3UCH PHENOMENA HAVE BEEN REPEATEDLY DOCUMENTED G. Clément, Fundamentals of Space Medicine, Space Technology Library 23, DOI 10.1007/978-1-4419-9905-4_6, © Springer Science+Business Media, LLC 2011





&UNDAMENTALSOF3PACE-EDICINE

Figure 6.1. Fight Scene of the Movie “Lady Killer” (1933) by Director Roy Del Ruth, Featuring James Cagney, Douglas Dumbrille, Mae Clarke, Raymond Hatton, and Russell Hopton. (Credit Warner Bros).

INOPERATIONALSETTINGSSUCHASREMOTESTATIONSINTHE!NTARCTICA UNDERSEAHABITATS AND MOST PERTINENTLY IN SPACECRAFT (OWEVER THE FACT THAT OBSERVATIONS ARE MADE AND OBSERVEDBYPEOPLEWHOACTUALLYSHARETHEEXPERIENCELIMITSTHERELIABILITYOFDATA #REWMENȃWINTERINGOVERȄFORMONTHSIN!NTARCTICSTATIONS WHICHCORRESPONDS TOTHESUMMERSEASONINTHE.ORTHERNHEMISPHERE HAVESHOWNANINCREASEOFIN STRESS RELATEDSYMPTOMSOFANXIETY DEPRESSION INSOMNIAANDHOSTILITY;3ANDALETAL =)NSPACE WHERETHESTRESSOFISOLATIONISCOMPOUNDEDBYTHESTRESSOFPROLONGED WEIGHTLESSNESS PROBLEMS CAN GO BEYOND HOSTILITY AND ANXIETY !STRONAUTS USUALLY COMPLAINOFVARIOUSPSYCHOSOMATICSYMPTOMS INCLUDINGSLEEPDISTURBANCE TIMEDIS ORIENTATIONANDHEADACHES4IMECOMPRESSIONANDHEAVYWORKSCHEDULESHAVELEDTO HARSH DISAGREEMENTS BETWEEN ASTRONAUTS AND GROUND CONTROL CREWS WITH THE ASTRO NAUTSINSPACEFEELINGRUSHEDANDTHECONTROLLERSON%ARTHGROWINGIMPATIENT 4HESEPROBLEMSAREAMPLIʄEDBYTHEDIFʄCULTIESOFLIVINGINMICROGRAVITYHYGIENE ROUTINESARETIMECONSUMINGANDLABORIOUSFOODDOESNOTTASTETHESAMEANDSPICES MUSTBEADDEDFORʅAVORPRIVACYISLIMITEDTHEENVIRONMENTISNOISYTHECOUNTERMEA SURESMAYREQUIREEXTRAEFFORTANDTIME CONSUMINGACTIVITY&IGURE ANDMOTIVA TIONTODOTHEREQUIREDCOUNTERMEASURESBECOMESINCREASINGLYDIFʄCULT2ELATEDTOTHE QUESTIONOFEXERCISINGINSPACEISTHEPROBLEMOFLIMITEDBATHINGFACILITIES4HEWATER

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



Figure 6.2. Astronaut Pete Conrad Exercises in Skylab. During a Long-Duration Mission, Daily Exercise Sessions Require Extra Effort and Motivation (No Shower!) and Are Very Time-Consuming. (Credit NASA).

DISPERSEDFROMPERSPIRATIONDURINGEXERCISEMUSTBECOLLECTED ANDTHEREISNOSHOWER JUSTSPONGEBATH)NADDITION THEPHYSIOLOGICALADAPTATIONSTOMICROGRAVITYDESCRIBED INPREVIOUSCHAPTERSCHALLENGEANDSTRESSINDIVIDUALS ANDTHUSIMPACTINTERPERSONAL INTERACTION CONCENTRATION ANDABILITYTOPERFORMGROUPANDINDIVIDUALWORK !SSPACEʅIGHTSBECOMELONGERANDMOREROUTINEWITHTHEREWARDSLESSSATISFYING THEINTENSEEFFECTSOFBEINGISOLATEDTAKETHEIRTOLL-OREPROBLEMSINPSYCHOLOGICAL ADJUSTMENTSAREEXPECTED"ECAUSEOFTHETECHNICALANDPRECARIOUSNATUREOFFUTURE INTERPLANETARY LONG DURATION MISSIONS THE SLIGHTEST UPSET IN ASTRONAUT PERFORMANCE ANDBEHAVIORCOULDHAVEDISASTROUSEFFECTSONTHEMISSION 4YPICALLY WHEN AN INDIVIDUAL OR SMALL GROUP OF INDIVIDUALS IS REMOVED FROM A SOCIALENVIRONMENTANDPUTINTOANISOLATEDANDCONʄNEDENVIRONMENT FOURGROUPSOF SYMPTOMSARETOBEEXPECTED;(ARRISONAND#ONNORS =4HEʄRSTGROUPINCLUDES MENTAL DEʄCIENCIES DECREASED ATTENTION AND CONCENTRATION LEARNING PROBLEMS AND HALLUCINATIONS4HESEPROBLEMSRAISECONCERNSWHENOPERATINGINDANGEROUSENVIRON MENTSSUCHASSPACE)NAWORSECASESCENARIO AWARNINGLIGHTMAYBEMISSEDCAUSING ACATASTROPHETOOCCUR4HESECONDGROUPISADECLINEINMOTIVATIONWHENTHEINDI VIDUALȀSORTHEGROUPȀSPERCEPTIONSOFTHEREWARDSINHERENTTOTHESITUATIONDOESNOT OUTWEIGHITSCOSTS"YCOMPARISON INTHEEARLYSPACEMISSIONSINWHICHASTRONAUTS



&UNDAMENTALSOF3PACE-EDICINE

WERE TREATED AS HEROES SPACEʅIGHT BECOMES MORE ROUTINE THUS CREATING A SITUATION WHEREREWARDISPERCEIVEDASDECLINING;(ELMREICHETAL =4HETHIRDCATEGORYOF PROBLEMSISSOMATICCOMPLAINTS SUCHASSLEEPDISTURBANCES HEADACHES UPSETSTOM ACHS ANDCONSTIPATION!LLOFTHESECOMPLAINTSHAVESOMEBASISINTHEPHYSICALNATURE OF THE ENVIRONMENT BUT CAN ALSO EASILY BE EXACERBATED BY OR EVEN CAUSED BY THE UNUSUALLEVELSOFSTRESSFOUNDINTHATENVIRONMENT#HANGESINMOODANDMORALECOM PRISETHEFOURTHCATEGORY )TISINTERESTINGTONOTETHATDURINGTHEʄRSTSEVERALWEEKSOFAMISSIONIN!NTARCTICA THEINTERPERSONALPROBLEMSDONOTPLAYAMAJORROLE7HENCREWMEMBERSʄRSTARRIVE THEYDONOTPOSSESSENOUGHKNOWLEDGEABOUTTHEIRMISSIONANDSURROUNDINGSTOFOR MULATETHEIROWNIDEAS(ENCE THEYAREWILLINGTOFOLLOWWHATEVERTHELEADERSAYS !FTERTHEINITIALSHOCKOFTHEENVIRONMENTWEARSOFF ANDCREWMEMBERSGETTOKNOW THEIR SURROUNDINGS SOMEWHAT BETTER THEY BEGIN TO REBEL AGAINST AUTHORITY AND EACH OTHER4HEINCREASEINMOODDISTURBANCEAFTERTHEMID POINTOFWINTERISOLATIONFOUND INSOMESTUDIESSUGGESTSTHEEXISTENCEOFAȃTHIRDQUARTERPHENOMENONȄTHATISMORE PSYCHOSOCIALTHANENVIRONMENTALINNATURE4HISPHENOMENONISINDEPENDENTOFMIS SIONDURATION)TRESULTSFROMTHEREALIZATIONTHATTHEMISSIONISONLYHALFCOMPLETED ANDTHATAPERIODOFISOLATIONANDCONʄNEMENTEQUALINLENGTHTOTHEʄRSTHALFREMAINS ;"ECHTELAND"ERNING = 4OFULLYUNDERSTANDGROUPDYNAMICS INDIVIDUALPSYCHOLOGICALHEALTH ANDFACTORS THATBOTHHINDERANDHELPDAILYLIFEONTHE)33 RESEARCHERSRECORDEDCREWANDCREW GROUNDACTIVITIESDURINGTHEʄRSTNINE%XPEDITIONS!COMPUTERIZEDQUESTIONNAIREWAS THE MAIN TOOL USED TO COLLECT THE DATA AND INCLUDED QUESTIONS FROM THREE STANDARD MOODANDINTERPERSONALGROUPCLIMATEQUESTIONNAIRESASWELLASACRITICALINCIDENTLOG )NPUTWASCOLLECTEDONAWEEKLYBASISFROMTHECREWMEMBERSINSPACE GROUNDPER SONNELAT.!3!#ENTERSINTHE5NITED3TATES ANDTHE2USSIANMISSIONCONTROLPERSON NEL!STHECREWMEMBERSADJUSTEDTOTHEIRNEWENVIRONMENTONBOARDTHE)33 THERE WASEVIDENCEOFIMPROVEDMENTALHEALTH2ESULTSOFTHESTUDYALSOSHOWEDEVIDENCE THATTHEIRMOODASWELLASTHESOCIALCLIMATEONBOARDIMPROVEDWITHTIME4HECON ʅICTSTHATDIDOCCURAMONGTHECREWASWELLASBETWEENTHE53AND2USSIANTEAMSDID NOTAPPEARTOBERELATEDTOMOODORSOCIALCLIMATEVARIABLES4HESTUDYIDENTIʄEDCOM MUNICATIONANDGEOGRAPHICSEPARATIONASTHEKEYCHALLENGESTOLEADERSHIPANDMISSION MANAGEMENT;+ANASETAL = 0SYCHOLOGICALMONITORINGANDSUPPORTFORMISSIONSTO-ARSWILLBERESTRICTEDASA RESULTOFTHEFACTTHATREAL TIMESPACE TO GROUNDCOMMUNICATIONSWILLNOTBEPOSSIBLE FORMOSTOFTHEMISSION4HEʄRSTASTRONAUTEXPLORERSWHOVISIT-ARSWILLALSOBETHE ʄRST HUMAN BEINGS TO LOSE A DIRECT VISUAL LINK WITH %ARTH BECAUSE OF THE ENORMOUS DISTANCESINVOLVED&IGURE (OWINDIVIDUALSWILLRESPONDTOTHEȃ%ARTHOUT OF VIEWPHENOMENONȄISNOTKNOWN1UITEANUMBEROFREPORTSFROMASTRONAUTSSUGGEST THATTHEPSYCHOLOGICALIMPORTANCEOFLOOKINGBACKTO%ARTHFROMSPACEISOFSIGNIʄCANT IMPORTANCE)TISPOSSIBLETHATNOTBEINGABLETOSEETHE%ARTHMIGHTINDUCEFEELINGSOF ANXIETY SADNESS DEPRESSIVE REACTIONS OR EVEN A LOSS OF COMMITMENT TO THE USUAL %ARTH BOUND SYSTEM OF VALUES AND BEHAVIORAL NORMS ,OGICALLY WE CAN CONCLUDE THAT MISSION PERFORMANCE MIGHT THEN BE ADVERSELY AFFECTED AS WOULD INDIVIDUAL BEHAVIOR INTERPERSONAL INTERACTIONS AS WELL AS THE ACCEPTANCE OF GUIDANCE FROM MISSIONCONTROLLERSON%ARTH;+ANASAND-ANZEY =

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



Figure 6.3. Left: Earth and Sun Viewed from Mars. The Right Half of This Illustration Shows What the Rovers and Astronauts Would See if They Looked Toward the Earth When the Distance Between Earth and Mars Is the Shortest (50–60 Million km). (Credit NASA).



!NALOGS

-UCHOFOURUNDERSTANDINGOFHUMANBEHAVIORANDPERFORMANCEINSPACEHASBEEN OBTAINEDFROMTHESTUDYOFANALOGENVIRONMENTSSUCHAS!NTARCTICRESEARCHSTATIONS POLAREXPEDITIONS NUCLEARSUBMARINES UNDERSEAHABITATS OILDRILLINGRIGS SMALLRURAL COMMUNITIES ANDSPACESIMULATOREXPERIMENTS !NALOGSARENOTPERFECTSIMULATIONSOFTHESPACEENVIRONMENT.ONE FORINSTANCE HAVETHECONDITIONOFMICROGRAVITY4HEREAREALSODIFFERENCESWITHRESPECTTOCHARAC TERISTICSOFCREWMEMBERS PROCEDURESFORSCREENINGANDSELECTION CREWSIZE MISSION OBJECTIVESANDDURATION$ESPITETHESEDIFFERENCES ANALOGENVIRONMENTSARETHEONLY WAYTOSTUDYBEHAVIORALIMPACTSOFISOLATION CONʄNEMENT ANDSTRESSOVERLONGPERI ODSOFTIME .UCLEARSUBMARINESHAVELONGBEENTHEFOCUSOFANALOGSTUDIESFORLONGDURATION SPACEʅIGHTBECAUSEOFTHEISOLATIONANDDANGER ASWELLASTHECONʄNEDCLOSEQUARTERS 7HEREASDIESELSUBMARINESONLYSTAYBELOWTHESURFACEAFEWDAYS NUCLEARSUBMA RINESSPENDTHEBETTERPARTOFMONTHSORMOREUNDERWATER4HEINCIDENCERATEOF DEBILITATIVEPSYCHIATRICILLNESSESAMONGTHECREWISRELATIVELYLOW WITHABOUTǻ CASES PER   MEN 0SYCHIATRIC SYMPTOMS GENERALLY OBSERVED INCLUDED ANXIETY INTERPERSONAL PROBLEMS SLEEP PROBLEMS PERFORMANCE DECREMENT AND DEPRESSION AMONGAHOSTOFOTHERS;7EYBREWAND.ODDIN =4HELOWINCIDENCEMAYBEDUE TO THE FACT THAT SUBMARINERS ARE SOME OF THE MOST THOROUGHLY SCREENED TESTED AND TRAINEDINDIVIDUALSINTHEWORLD!LSO THEPRESENCEONBOARDOFANUCLEARSUBMARINE MEDICALOFʄCERWHOHASSPECIALIZEDTRAININGINPSYCHIATRYMAYEXPLAINTHELOWINCI DENCERATEFORPSYCHIATRICSYMPTOMS 0ERHAPSTHECLOSESTOPERATIONALANALOGOFSPACEOCCUPANCYISTHEUNDERSEAHABITAT WHERE AQUANAUT DIVERS LIVE AND WORK ON THE OCEAN ʅOOR WITH A DEGREE OF ISOLATION SIMILAR TO THAT IN SPACE &IGURE   5NDER THESE CIRCUMSTANCES AND IN !NTARCTIC

3PACESIMULATOREXPERIMENTSALLOW HOWEVER TOCONTROLSOMEOFTHESEASPECTS





&UNDAMENTALSOF3PACE-EDICINE

Figure 6.4. The NASA Extreme Environment Mission Operations (NEEMO) in the Aquarius Habitat Off Key Largo and 19 m Below the Surface Provides a Convincing Analog to Space Exploration. ISS Crewmembers, as Well as NASA Employees and Contractors, Are Deployed There for up to 3 Weeks at a Time. They Experience Some of the Same Tasks and Challenges Under-Water as They Would in Space. (Credit NASA).

S TATIONSANDSUBMARINEOPERATIONSASWELL OBSERVATIONALMEASUREMENTSHAVEFOCUSED UPON CRITICAL INDIVIDUAL AND GROUP FACTORS THAT INʅUENCE PERFORMANCE EFFECTIVENESS ANDINTERPERSONALRELATIONS 0ALINKAS;=DESCRIBES!NTARCTICAASTHEBESTANALOGTOTHESPACEENVIRONMENT "ECAUSEOFTHEEXTREMENATUREOFTHEENVIRONMENT RESEARCHERSMUSTWINTER OVERFORǻ MONTHSOUTOFTHEYEAR$URINGTHISPERIOD THEREISLITTLECONTACTWITHTHEOUTSIDEWORLD ANDGROUPSARECONʄNEDTOTHEIRBARRACKSBECAUSEOFTHEEXTREMETEMPERATURES3EVERAL FEATURESOF!NTARCTICRESEARCHSTATIONSAREPARTICULARLYSIMILARTOOUTERSPACE!NTARCTIC FACILITIESANDSPACEFACILITIESHAVESIMILARSCIENTIʄCANDPOLITICALOBJECTIVES4HEYARE ALSOSIMILARINA THENATUREOFTHEWORK WHICHISPRIMARILYSCIENCE EXPLORATION AND SUPPORTB THEHETEROGENEITYOFTHECREWSTHATCOMPRISEMILITARYANDCIVILIANMENAND WOMEN !NTARCTICVETERANSANDNOVICESC THEHIGHLEVELOFSKILLSD THEORGANIZATION OFTHEMISSION LIKETHEDIVISIONOFLABOR CHAINOFCOMMANDANDE THEROTATIONALSTRUC TUREOFTOURSOFDUTY;0ALINKAS =/UTERSPACEAND!NTARCTICAAREALSOSIMILARINTHAT THEIRENVIRONMENTSAREHAZARDOUSANDSTRESSFULTOWORKINANDTHECREWSAREHETEROGE NEOUS CONʄNED AND ISOLATED FROM THE LARGER SOCIETY "ECAUSE OF THESE SIMILARITIES !NTARCTICAHASSERVEDASONEOFTHEPRIMARYMEANSOFGATHERINGTHEPSYCHO SOCIOLOGICAL DATAFORTHE)33ANDFUTUREINTERPLANETARYMISSIONS;(ARRISONETAL = 4OSOMEEXTENT ANALOGSANDSPACEMISSIONSPROVIDECOMPARABLEREPORTSOFPSYCHO LOGICALPROBLEMS4ABLE 4HISISMAINLYBECAUSEOFTHECONDITIONSOFISOLATIONAND

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT Table 6.1.



Reported Psychological Problems During Spaceflight and Analogs.

Reported Problems

ISS/Mir

Shuttle

Submarines

Polar Expeditions

Interpersonal conflicts

Documented

Documented

Documented

Documented

Sleep disturbances

Documented

Documented

Documented

Documented

Boredom, restless

Anecdotal

Documented

Documented

Performance decrement

Anecdotal

Documented

Documented

Decline in group compatibility

Anecdotal

Anecdotal

Documented

Substance abuse

Anecdotal

Anecdotal

Documented

Figure 6.5. Number of Diary Entries Classed by Categories During Expeditions in French Antarctica. (Adapted from Stuster et al. [1999]).

CONʄNEMENT(OWEVER FORSPACEMISSIONS MOSTDATACOMESFROMANECDOTALREPORTS LIKEDIARIES STORIES PERSONALBOOKS ANDINTERVIEWS;"ONDAR "URROUGH  #HAIKIN #OLLINS ,EBEDEV ,INENGER =-ETHODICALLYDOCU MENTEDDATAISLACKING /NEMETHODUSEDBYPSYCHOLOGISTSTOEVALUATETHEEFFECTSOFCONʄNEMENTANDISOLA TIONDURINGAWINTER OVERIN!NTARCTICA FOREXAMPLE ISTOANALYZETHEDIARIESOFTHE CREWMEMBERS4HEASSUMPTIONISTHATTHEFREQUENCYTHATANISSUEISMENTIONEDINA DIARYREʅECTSTHEIMPORTANCEOFTHATISSUE3TUSTERETAL;=ANALYZEDNINEDIARIES FROMSEVERALEXPEDITIONERSIN&RENCH!NTARCTICARANGINGFROMTODAYS WRITTEN BYTHESTATIONLEADERS THEMEDICALOFʄCERS ANDTHETECHNICIANSINCHARGEOFCOMMUNI CATIONS4HESEREPORTSCLEARLYINDICATEMORENEGATIVEEXPERIENCESDURINGTHETHIRDQUAR TEROFISOLATIONANDCONʄNEMENTINAN!NTARCTICSTATION REGARDLESSOFDURATIONOFTHE EXPEDITION)TISALSOINTERESTINGTONOTETHAT WHENGROUPEDINTOCATEGORIES THELARGEST NUMBERSOFDIARYENTRIES ANDPRESUMEDIMPORTANCEOFTHEISSUES CONCERNGROUPINTER ACTION COMMUNICATION WORKLOAD RECREATIONANDLEISURE ANDLEADERSHIP&IGURE 

&UNDAMENTALSOF3PACE-EDICINE

 

3PACESIMULATORS

4HE )SOLATION 3TUDY FOR %UROPEAN -ANNED 3PACE )NFRASTRUCTURE )3%-3) WAS A SIMULATIONEXPERIMENTCONDUCTEDBY%3!INTOPROVIDEPSYCHOLOGICALDATAON THEDAY TO DAYACTIVITIESOFASTRONAUTSDURINGALONG DURATIONISOLATIONANDCONʄNE MENTINSIDEAGROUND BASEDREPLICAOFASPACESTATION4HECREWFOR)3%-3)CONSISTED OFSIXMALES EACHFROMADIFFERENT%3!MEMBERSTATE!LLSUBJECTSWERECIVILIANSWHO HADBACKGROUNDSINSCIENCEANDENGINEERING4HEYWEREPLACEDFORA WEEKPERIODIN HYPERBARIC CHAMBERS AND MONITORED BY A ȃGROUNDȄ CONTROL TEAM 2ESULTS FROM A BATTERY OF PSYCHOLOGICAL TESTS PERFORMED SHOWED NO EVIDENCE OF SEVERE SOCIAL OR EMOTIONALCONʅICTSDURINGTHEEXPERIMENT (OWEVER OBSERVATIONSOFSOCIALINTERACTIONANDCOMMUNICATIONREVEALEDCONSIDER ABLECHANGESINTHECOMMUNICATIONʅOWAMONGTHECREWMEMBERS&IGURE !TTHE BEGINNINGOFTHECONʄNEMENT ALLSUBJECTSPARTICIPATEDINCOMMUNICATIONINARELATIVELY BALANCEDMANNER!TTHEEND SUBJECT$ WHOWASTHEMOSTDOMINANTSUBJECTBESIDETHE COMMANDER WAS TOTALLY ISOLATED AND THE COMMUNICATION OF ALL OTHER CREWMEMBERS REMAINED LIMITED TO TWO WAY COMMUNICATIONS WITH THE COMMANDER $ESPITE THESE PROBLEMS THEVOLUNTEERSWERESEENTOCOALESCEINTOATIGHTLYKNITGROUP EVENDEVELOP INGANAGGRESSIVEATTITUDETOWARDSTHEȃGROUNDȄCONTROLTEAM;3ANDALETAL = )NAMORERECENTEXPERIMENT SOCIALINTERACTIONSOFAMIXED GENDERCREWFROMʄVE COUNTRIES2USSIA #ANADA *APAN !USTRIA AND&RANCE WEREEVALUATEDDURINGA DAYISOLATIONSTUDYINA-IRSIMULATOR3&).#33  )NTHISSTUDY THECREWMEMBERS SOMETIMESEXECUTEDDIFFERENTʅIGHTPROGRAMSANDWEREHOUSEDINCOMPARATIVELYSEPA RATE MODULES !S PREDICTED SEVERAL INCIDENTS OCCURRED THAT COULD BE REGARDED AS A CONʅICT SITUATION BETWEEN CREWMEMBERS &OR EXAMPLE A ʄSTʄGHT TOOK PLACE AT THE .EW9EARȀSPARTY ANDA#ANADIANFEMALECREWMEMBERACCUSEDA2USSIANCREWMEM BEROFSEXUALHARASSMENT,ATER THECOMMANDERINFORMEDTHEȃGROUNDȄCONTROLTEAM ANDINSISTEDONTHEWITHDRAWALOFTHETWOSUBJECTSFROMTHESTUDYELSETOCLOSETHE HATCHBETWEENTHETWOMODULES)NACCORDANCEWITHHISREQUEST THEHATCHBETWEENTHE

Figure 6.6. Pattern of Communication at Different Days of the ISEMSI Study. The Thickness of the Arrows Indicates the Frequency of Occurrence. A, B, C, D, E, F Represents the Different Crewmembers, with C Being the Commander. The Center Island Represents the Overall Group, When, for Example, One Says, “Let’s Go Eat!” [Sandal et al., 1995].

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



CHAMBERSWASCLOSED&ROMTHISPOINTON FRUSTRATIONGREWMOREINTENSEAMONGTHE CREWMEMBERSANDTOWARDTHEȃPASSIVESUPPORTANDINSUFʄCIENTMANAGEMENTOFCRISISȄ BYTHEGROUNDCONTROLTEAM/NEVOLUNTEEREXPRESSEDAWISHTOLEAVETHECHAMBERAND DIDSO;.!3$! = 4HERESULTSOFTHESEEXPERIMENTSANDOTHERSARESOMEWHATCONSISTENTWITHWHATHAS BEEN PREVIOUSLY OBSERVED IN ACTUAL SPACEʅIGHTS 4HE ȃ5S VS 4HEM 3YNDROMEȄ IN PARTICULAR HAS APPEARED AT VARIOUS TIMES ON SPACEʅIGHTS AND IN !NTARCTIC STUDIES "ASICALLY THETEAMSOUTINTHEʄELDSEETHOSEWHOSTAYATBASEASSOFTANDWEAK4HEIR ATTITUDESEEMSTOBEȃ4HEYȀREBACKTHEREALLWARMANDCOZY
7HATDOTHEYKNOWABOUT WHATȀSGOINGONOUTHEREȄ4HEDISTANCEFROMACENTRALAUTHORITYSEEMSTOFORCETHE CREWTOASSUMEARESPONSIBILITYFORTHEMSELVESANDTHEIRENVIRONMENT!STHISHAP PENS THEYBEGINTOSEETHEȃOUTSIDEAUTHORITYȄASUNNECESSARY#ONʅICTSCANOCCURIF THECENTRALAUTHORITYPUSHESITSELFONTHECREW;.ICHOLASAND&OUSHEE = !TTHETIMEOFTHISWRITING THEREARESIXINDIVIDUALS INCLUDINGTHREE2USSIANS TWO %UROPEANS ANDONE#HINESE ALLMALE SEALEDINANISOLATIONCHAMBERATTHE)NSTITUTE OF-EDICAL0ROBLEMSIN-OSCOW4HEYARETHECREWOFTHEȃ-ARSȄSIMULATEDMIS SIONTO-ARS WHICHBEGANIN*UNEANDISSCHEDULEDTOLASTDAYS4HEONLY WAYTHATTHISCREWCANCOMMUNICATEWITHTHEOUTSIDEWORLDISBYE MAIL4HEONLY PERSONALCONTACTTHEYHAVEISWITHEACHOTHER6OICECONTACTISMAINTAINEDWITHMIS SIONCONTROLLERSINTHESIMULATEDCONTROLCENTER ASWELLASWITHFAMILYANDFRIENDSAS WOULDNORMALLYBETHECASEDURINGAREALSPACEMISSION&IGURE  4HECOMMUNICATIONTRANSMISSIONLATENCYISSIMULATEDWITHABUILT IN MINDELAY ADDED TO MESSAGES SENT TOFROM THE -ISSION #ONTROL CENTER $URING THE ȃMISSION ASTHENIAȄ THECREWWILLSIMULATEALLELEMENTSOFTHE-ARSMISSIONINCLUDINGTRAVELING TO-ARS ORBITINGTHEPLANET LANDING ANDTHENRETURNINGTO%ARTH4HEYMUSTBESELF RELIANT ORGANIZINGMOSTOFTHEIRDAILYTASKSTHEMSELVES4HEYAREALSORESPONSIBLEFOR MONITORING THEIR OWN HEALTH AND PSYCHOLOGICAL STATES MONITORING CONTROLLING AND MAINTAININGALLȃʅIGHTȄSYSTEMS INCLUDINGLIFESUPPORTCONTROLLINGRESOURCECONSUMP TIONEXECUTINGSTANDARDANDNON STANDARDCLEANINGANDMAINTENANCEANDʄNALLY FUL ʄLLINGSCIENTIʄCINVESTIGATIONS !STANDARD DAYWEEKISMAINTAINEDTHATINCLUDESDAYSPERWEEKOFF!SWORK GOESON AROTATINGSHIFTSCHEMEHASBEENIMPLEMENTED4ODETERMINETHEEFFECTS OFDECREASEDWORKCAPACITY ILLNESS ORONBOARDSYSTEMSFAILURES BOTHSTANDARDAND NON STANDARDEMERGENCYSITUATIONSWILLBESIMULATED4HECREWWILLBEDIVIDEDINTO TWO GROUPS OF THREE DURING THE ȃ-ARS SURFACE OPERATIONSȄ PHASE OF THE SIMULATION 7HENTHEȃLANDINGPARTYȄEXITSFORTHE-ARTIANSURFACE THEHATCHBETWEENTHE-ARTIAN SIMULATIONMODULEANDTHERESTOFTHEFACILITYWILLBECLOSED)TWILLONLYBEOPENED AGAINWHENTHELANDINGPARTYRETURNSFROMTHESIMULATED-ARSSURFACEVISIT  4HEMUTINYOFTHE3KYLAB ASTRONAUTSAGAINST-ISSION#ONTROLISTHEPERFECTEXAMPLE!LLTHEASTRONAUTS OFTHE3KYLAB MISSIONWEREʄRST TIMEʅYERSROOKIES "EFORETHEYGOTADJUSTED -ISSION#ONTROLTRANS FERREDTHESAMEBUSYSCHEDULETOTHEMASTHEIRPREDECESSORSHADKEPTINTHESPACESTATION!FTERTHEIRCOM PLAINTABOUTAHEAVYWORKLOADDIDNOTRECEIVEENOUGHATTENTIONBYTHEGROUNDCONTROLLERS THE3KYLAB  ASTRONAUTSDECLAREDANUNSCHEDULEDDAYOFFTO-ISSION#ONTROLANDPROCEEDEDTOTURNOFFTHERADIOWHILE THEYGOTSOMEREST4HISMUTINYLEDTOMUCH NEEDEDWORKLOADADJUSTMENTS;3HAYLER =0ERHAPSASA RESULTOFTHISEVENT ARULESTATESTHATATLEASTONEMEMBEROFAN%XPEDITIONCREWONBOARDTHE)33SHOULDBE ASPACEʅIGHTVETERAN

&UNDAMENTALSOF3PACE-EDICINE



Figure 6.7. International Space University’s Alumnus Diego Urbina Is a Member of the SixPerson Crew in the Mars-500 Isolation Facility. (Credit Diego Urbina).



3PACEMISSIONS

4HEFORMER3OVIET5NIONHASHADEXTENSIVEEXPERIENCEINOPERATINGACREWEDSPACE STATIONOVERLONGPERIODSOFTIMEBEGINNINGINWITHTHELAUNCHOFTHEʄRSTSPACE STATION 3ALYUT $ISAGREEMENTSBETWEENTHE2USSIANCREWAND-ISSION#ONTROLOVER WORKOVERLOAD ORREGULATIONSOFCREWACTIVITIESIMPOSEDBY-ISSION#ONTROL WERE REPORTEDFROMSEVERALMISSIONS;+ELLYAND+ANAS = 3OMEOFTHEPROBLEMSTHATHAVEBEENOBSERVEDABOARD3OVIETSTATIONSINCLUDEA GENERAL NERVOUS OR MENTAL TIREDNESS CALLED ȃASTHENIAȄ !STHENIA SYMPTOMS INCLUDE HYPERSENSITIVITY IRRITABILITY ANDHYPOACTIVITYINITSEARLYSTAGES4HESESYMPTOMSARE SOMETIMESFOLLOWEDBYPSYCHOSOMATICILLNESSANDSLEEPDISORDERS!STHENIAOCCURS PRIMARILY IN THE MONOTONOUS LATER PORTIONS OF THE MISSION /NCE RECOGNIZED IT IS TREATEDTHROUGHAMANIPULATIONOFWORKSCHEDULESTOPROVIDEMOREFREETIMEANDSTIM ULATION ANDTHROUGHINCREASEDAUDIOVISUALCOMMUNICATIONSWITHFRIENDSANDFAMILY ;+ANAS =!NOTHERPROBLEMTHATMANIFESTEDITSELFONBOARD3OVIETSTATIONSWAS INTERPERSONALTENSION4HE3OVIETPROCLIVITYTOWARDSTHEȃCOLLECTIVEȄCAUSESTHECOS MONAUTSTOSUPPRESSTHEIRHOSTILEFEELINGSTOWARDSONEANOTHERINTHEINTERESTOFTHE MISSIONASAWHOLE;3ANTY = 4HECONDITIONSTHATEXISTINLONG DURATIONSPACEMISSIONSINCREASETHEPOTENTIALFOR ADVERSEEFFECTSALREADYREPORTEDDURINGRELATIVELYSHORT DURATIONMISSIONSEG IRRITA BILITY DEPRESSION SLEEPDISTURBANCES ANDPOORPERFORMANCEOFBOTHGROUPANDINDI VIDUAL  $URING THE JOINT .!3! -IR MISSIONS -ARCH ǻ*UNE  SEVERAL EVENTSCAUSEDTENSIONAMONGTHECREWANDBETWEENTHECREWANDPERSONNELAT-ISSION #ONTROL 4ABLE   $IFFERENCES IN MOOD AND GROUP PERCEPTIONS BETWEEN 53 AND 2USSIAN CREWMEMBERS AS WELL AS BETWEEN CREWMEMBERS AND -ISSION #ONTROL PERSONNELWEREALSOIDENTIʄEDDURING)33MISSIONS

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT Table 6.2.



List of Events Leading to Psychological Disturbances During the NASA-Mir Space Missions. Adapted from Ark and Curtis [1999].

s #REWCHANGEAT, WEEKS s -ISSIONEXTENDEDBYWEEKS s -INIMALCONTROLOVERIN mIGHTWORKSCHEDULE s 7ORKOVERLOADUNDERLOAD s 3OCIALWITHDRAWAL s $EATHOFFAMILYMEMBER s $ANGEROUSATMOSPHEREETHYLENEGLYCOLANDCONTAMINANTLEAKS s &IREDECOMPRESSIONLOSSOFMODULE LOSSOFPOWERFREEDRIFT COMMUNICATIONSYSTEM failures s !NGERWITHGROUNDCONTROLMANAGEMENThUSVSTHEMvSYNDROME s #REWFRICTION

Table 6.3. The Countermeasures for Psycho-Sociological Issues of Spaceflight Are Individual and Crew Selection, Training, and In-Flight Support. Selection Best psychological profile Appropriate skills Team player Training Interpersonal communication Group dynamic and group problem-solving Multicultural sensitivity Performance feedback monitoring Support In-flight counseling Communication with family & friends Scheduled breaks in routine



2ULES

.EARLYALLESSENTIALHUMANFUNCTIONSDURINGLONG DURATIONSPACEMISSIONSWILLDEPEND CRITICALLYUPONINDIVIDUALANDGROUPBEHAVIOR3ELECTION TRAINING ANDORGANIZATIONAL SUPPORTARETHEFOCUSOFHUMANBEHAVIORALINITIATIVES4ABLE  4HEʄRSTPRIORITYINCONSIDERINGTHEEFFECTSOFINDIVIDUALFACTORSUPONPERSONALADJUST MENTTOASPACEMISSIONISTHESCREENINGANDSELECTIONOFPROSPECTIVEPARTICIPANTS)N !NTARCTICA AGOODȃʄELDPERSONȄISONEWHOHASAGOODKNOWLEDGEOFLIVINGANDWORK INGINTHENEWENVIRONMENT ANDISCOMMITTEDTOSCIENCEANDEXPLORATION4HISINDIVIDUAL ISAUTONOMOUSANDCANFUNCTIONWITHOUTDIRECTSUPERVISION(EORSHEALSOSHOULDALSO HAVEACERTAINAMOUNTOFINTEGRITYANDMUSTACCEPTONELEADER)NDEED INAHOSTILEENVI RONMENT THEREISROOMFORINDIVIDUALITY BUTNOTFORȃTOOMANYCHIEFSȄ;3TUSTER =

&UNDAMENTALSOF3PACE-EDICINE



)N GENERAL THESE PRINCIPLES CAN BE APPLIED EFFECTIVELY TO SPACE MISSIONS 4HE A STRONAUTSHOULDHAVEANINTIMATEKNOWLEDGEOFTHEENVIRONMENTINWHICHHESHEWILL BESPENDINGALOTOFTIMEANDBECOMMITTEDTOTHEMISSIONOFWHICHHESHEWILLBEA PART0ALINKASETAL;A=INHISREVIEWOFTHELITERATUREFOUNDTHATINTROVERTEDINDI VIDUALS THOSEWHOAREȃMOREINNER DIRECTED QUIET RETIRINGTYPESȄ TENDTOADAPTAND PERFORMBETTERIN!NTARCTICSITUATIONSTHANDOEXTROVERTS 4RAININGSHOULDBEBOTHDIDACTICALANDEXPERIENTIAL4HEGOALISTOSENSITIZEBOTH THECREWMEMBERSANDMONITORINGGROUNDPERSONNELTOTHEINʅUENCESOFSOCIO CULTURAL FACTORS SUCHASCULTUREANDLANGUAGEDIFFERENCES4EAMBUILDINGANDCONʅICTRESOLU TIONEXERCISESSHOULDALSOBEINCLUDEDINPREʅIGHTACTIVITIES )N ʅIGHTSUPPORTISPROVIDEDBYTHEʅIGHTSURGEONSANDPSYCHOLOGISTSONTHEGROUND ASWELLASFAMILYORFRIENDS ANDINCLUDESSURPRISEGIFTSANDEVENTSTOBREAKTHEROUTINE )NDIVIDUALS ARE ALSO ENCOURAGED TO TALK WITH ONE ANOTHER TO RESOLVE INTERPERSONAL DIFʄCULTIES 4HECOUNTERMEASURESSELECTION TRAINING ANDSUPPORT AREFURTHERDETAILEDINTHE FOLLOWINGSECTIONS

 )NDIVIDUALSELECTION !TTHEINDIVIDUALLEVEL SELECTIONSTRATEGIESHAVETWO FOLDOBJECTIVESTOELIMINATEUNʄT ORPOTENTIALLYUNʄTAPPLICANTS ANDTOSELECTFROMOTHERWISEQUALIʄEDCANDIDATESTHOSE WHOWILLPERFORMOPTIMALLY!DISTINCTIONISTHEREFOREMADEBETWEENȃSELECT OUTȄAND ȃSELECT INȄCRITERIA 

3ELECT OUTCRITERIA

4HEʄRSTOBJECTIVEISTOȃSELECT OUTȄORDISQUALIFYANYCANDIDATEWITHAHISTORYOFA PSYCHIATRICDISORDER CURRENTPSYCHIATRICSYMPTOMS OROTHERCHARACTERISTICSTHATPLACE HIMORHERATRISKFORAPSYCHIATRICDISORDERDURINGASPACEMISSIONȃ3ELECT OUTȄCRITE RIAAREMEDICALCRITERIASPECIFYINGTHOSEPSYCHIATRICDISORDERS WHICHWOULDBEDIS QUALIFYING4HESEDISORDERSINCLUDESCHIZOPHRENIA MAJORDEPRESSION ANDALLTHEOTHER PSYCHIATRICDISEASESLISTEDIN4ABLE4OACHIEVETHISOBJECTIVE SELECTIONPROCEDURES RELYUPONFORMALCLINICALEVALUATIONSANDUSEOFSTANDARDIZEDPSYCHOMETRICTESTS #LINICALEVALUATIONSGENERALLYAREINTHEFORMOFASTRUCTUREDPSYCHIATRICINTERVIEW WITHATLEASTTWOINDEPENDENTPSYCHIATRISTS%ACHPSYCHIATRISTASKSTHESAMEQUESTION INTHESAMEORDERANDGENERALLYINTHESAMEMANNERTOAVOIDTHEPROBLEMKNOWNAS INTERVIEWERBIAS4HEINTERVIEWSARECONDUCTEDTOCOUNTERACTTHETENDENCYOFAPPLI CANTSTOMINIMIZEPSYCHOLOGICALSYMPTOMSȃSTAYINGCLEANȄ 0ATRICIA3ANTYGIVESTHE FOLLOWINGEXAMPLEINHERBOOK#HOOSINGTHE2IGHT3TUFF;=INSTEADOFASKINGTHE QUESTION ȃ(AVEYOUEVERBEENDEPRESSEDȄWHEREMOSTHEALTHYSUBJECTSWOULDREAL IZEITȀSNOTAGOODTHINGTOBEDEPRESSEDANDWOULDPROBABLYANSWERȃNO ȄTHEQUESTION ISFORMULATEDINTHEFORMOFAREQUESTǻȃ4ELLMEABOUTTHETIMEWHENYOUHAVEBEEN MOSTSADINYOURLIFEȄǻWHICHMAKESITHARDFORTHESUBJECTTOESCAPEFROMGIVING SOMECLINICALINFORMATIONONTHETOPIC 4OASSISTTHECLINICIANINOBJECTIVELYDETERMININGWHETHERORNOTANAPPLICANTISA ȃRISK TO ʅIGHT SAFETY Ȅ A SERIES OF PSYCHOMETRIC TESTS IS GENERALLY ADDED TO THE PSYCHIATRIC INTERVIEW 4HESE TESTS INCLUDE SELF REPORT QUESTIONNAIRES SUCH AS THE

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT Table 6.4.



MMPI Scale. The First Three Measurements (Validity Scale) Indicate How Well the Candidate Responded to the Test. The Other Measurements Indicate the Scores for Each Disqualifying Psychiatric Disorders. Adapted from Santy [1994].

LnAVALIDITYSCALEHIGHVALUESINDICATEEVASIVENESS EG DIFFERENTRESPONSESTOABOUTTHE same questions FnAVALIDITYSCALEMEASURINGTHETENDENCYTOPRESENTONESSELFONANOVERLYFAVORABLELIGHT (low score = more favorable) KnAVALIDITYSCALEMEASURESDEFENSIVENESS EG UNDERREPORT NOTCOMPLETELYHONESTIN answering personal questions (high score = more defensive) Hs – Hysteria D – Depression Hy – Hypochondriasis Pd – Psychopathic Deviation Ma – Mania Mfn-ASCULINITY&EMINITY Pa – Paranoia Pt – Psychasthenia Sc – Schizophrenia Si – Social Introversion

Note: The Mf score is not considered of any significance in defining sexual orientation: High scoring are described as sensitive, aesthetic, passive; low scoring are described as aggressive, rebellious, and unrealistic.

-INNESOTA -ULTIPHASIC 0ERSONALITY )NVENTORY --0) AND THE -ILLION #LINICAL -ULTIAXIAL)NVENTORY-#-) 4HESETESTSHAVEBEENSTANDARDIZEDAGAINSTANORMAL POPULATION ANDMOSTOFTHEMHAVEBUILT INSCALESTHATDETECTWHETHERTHEAPPLICANTS FAKERESPONSESTOTESTQUESTIONSINTRYINGTOCONCEALPATHOLOGY/THERTESTSTRYTOCRE ATE A SITUATION IN WHICH THE PSYCHOLOGICAL ISSUES OF THE APPLICANT CAN BE REʅECTED 4HESEPROJECTIVEPERSONALITYTESTSINCLUDEFOREXAMPLETHE2ORSCHACH)NK"LOTTEST WHERETHESUBJECTȀSASSOCIATIONTOAMBIGUOUSINKBLOTSAREOBSERVEDANDSCORED)N OTHERPROJECTIVETESTSTHESUBJECTISASKEDTODRAWAPERSONORCOMPLETEASENTENCE 5SINGTHESEMETHODS 3ANTY;=REPORTSTHEINCIDENCEOFPSYCHIATRICDISORDERSIN ASTUDYOFASTRONAUTCANDIDATESTOBEǻ4HEPREVALENCERATESFORTHESEPSYCHI ATRICDISORDERSFOUNDINTHEAPPLICANTGROUPSAREVERYSIMILARTOTHERATESREPORTEDIN THEGENERALPOPULATIONǻ FROMANUMBEROFSTUDIES;2OBINSETAL = 

3ELECT INCRITERIA

4HESECONDOBJECTIVEISTOȃSELECT IN ȄORIDENTIFYANDSELECTCANDIDATESWITHCHARACTER ISTICSTHATPREDICTFOROPTIMUMPERFORMANCEINTHEISOLATED CONʄNED ANDHOSTILEENVI RONMENT OF SPACE 4HIS SELECTION DOES NOT HAVE SPECIʄC MEDICAL OR PSYCHIATRIC IMPLICATIONS ȃ3ELECT INȄ OR PSYCHOLOGICAL SELECTION CRITERIA IDENTIFY THOSE DESIRABLE PERSONALITYTRAITSORCHARACTERISTICSLINKEDTOASPECIʄCMISSIONȃBESTPERSONFORTHE JOBȄ 4YPICALLY THESETRAITSWOULDBETHOSEREQUIREDWHENAPPLYINGFORAQUALIʄEDJOB IE APTITUDEFORTHEJOB INTELLIGENCE ANDȃTEAMPLAYERȄ)NADDITION GIVENTHESTRESS ANDDIFʄCULTYOFTHESPACEENVIRONMENT QUALITIESSUCHASTHEABILITYTOTOLERATESTRESS

&UNDAMENTALSOF3PACE-EDICINE



TRAINABILITYANDʅEXIBILITY ANDMOTIVATIONAREMOSTIMPORTANT&INALLY SENSITIVITYTO SELFANDOTHERS EMOTIONALSTABILITY MATURITY ABILITYTOFORMSTABLEQUALITYINTERPERSONAL RELATIONSHIP AREPREREQUISITESFORDEALINGWITHSOCIOLOGICALISSUES;3ANTY = ȃ3ELECT INȄCRITERIAWEREEASYTOIDENTIFYFORTHEEARLYSPACEMISSIONS WHERETHE ASTRONAUTREQUIREMENTSWERELIMITEDTOHIGHPILOTINGSKILLS GOODSTRESSTOLERANCEHIGH ACCELERATION REDUCED PRESSURE HIGH TEMPERATURE AND OTHER STRESSORS AN ABILITY TO MAKE DECISIONS AND A STRONG MOTIVATION FOR THE SUCCESS OF THE MISSION RATHER THAN PERSONALOBJECTIVES(OWEVER WHENTHESPACEPROGRAMLATERALSOREQUIREDASTRONAUTS WITHENGINEERING SCIENTIʄC ORMEDICALBACKGROUND ANDNOTNECESSARILYPILOTINGSKILLS THEDEʄNITIONOFȃSELECT INȄCRITERIABECAMEMORECOMPLEX)NADDITION THEREHASBEEN LITTLEEVALUATIONOFASTRONAUTPERFORMANCEDURINGSPACEMISSIONS WHICHISAREQUISITE FORTHEVALIDATIONOFȃSELECT INȄCRITERIA0SYCHOLOGICALTESTSUSEDINTHEPASTHAVEALSO FAILEDTOʄNDSIGNIʄCANTPERSONALITYPREDICTORSOFPERFORMANCE!SARESULT ȃSELECT INȄ CRITERIAUSEDBYTHEPSYCHIATRISTSWEREREDUCEDFROMTHE'EMINITOTHE!POLLOPROGRAM ANDAREBASICALLYNOTUSEDFORTHESELECTIONOFSHUTTLEASTRONAUTS4ABLE  )TISINTERESTINGTONOTETHATDURINGTHEPSYCHOLOGICALEVALUATIONSOFTHECANDIDATES FORTHE-ERCURYSPACEPROGRAM TWOPSYCHIATRISTSSPENTOVERHONEACHCANDIDATE 4HISINCLUDEDTHETIMEFORTAKINGTHEPSYCHOMETRICTESTSTOEVALUATEMOTIVATIONAND PERSONALITY ANDPERFORMANCETESTSTOEVALUATEINTELLECTUALFUNCTIONSANDSPECIALAPTI TUDES0SYCHOLOGICALREACTIONSOFTHE-ERCURYAPPLICANTSWEREALSOMONITOREDDURING Table 6.5.

Summaries of Psychiatric and Psychological Selection Procedures in the U.S. Space Program (1959–1985). Adapted from Santy et al. [1991].

Procedure

Mercury

Gemini/Apollo

Shuttle

Number of hours for the psychiatric evaluation

30

10

3

Screening method

2 psych interviews

2 psych interviews

2 psych interviews

25 psych tests

10 psych tests

5 stress tests

1 stress test

1. Intelligence

1. General emotional stability

2. Drive and creativity

2. High motivation

3. Independence

3. Adequate “self” concept

4. Adaptive motivation

4. Quality of interpersonal relationships

“Select-in” criteria used by psychiatrists

None documented

5. Flexible  -OTIVATION 7. Lack of impulsivity Validation of criteria

Data not available

Not done

Not done

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



Figure 6.8. Astronaut Scott Carpenter During a Stress Test in a Heat Chamber Prior to His Flight on Board a Mercury Capsule. (Credit NASA).

STRESSEXPERIMENTSSIMULATINGSOMECONDITIONSOFTHEMISSION SUCHASCHANGEINPRES SURE ISOLATION NOISEANDVIBRATION ANDHEAT&IGURE  $URINGTHE'EMINI !POLLOANDEARLYSHUTTLEMISSIONS THEPSYCHOLOGICALEVALUATION OFCANDIDATESWASREDUCEDTOH ANDTHENUMBEROFPSYCHOMETRICTESTSDECREASEDFROM TO&ORSHUTTLECANDIDATES ONLYȃSELECT OUTȄCRITERIAAREUSEDTOELIMINATEPOSSIBLE DISRUPTIVEBEHAVIORS ANDTHEDURATIONOFTHEEVALUATIONDOESNOTEXCEEDH3ELECTION OFTHOSEINDIVIDUALSEVIDENCINGTHEHIGHESTPROʄCIENCY ASELECT INCRITERIA BASEDONTHE RESULTSOFPSYCHOLOGICALTESTSISABSENTAFTERTHESUCCESSOFTHEEARLYSPACEMISSIONS 

0SYCHOLOGICALPROʄLESOFASTRONAUTSANDCOSMONAUTS

5SINGDATACOLLECTEDOVERYEARSOFCANDIDATEPSYCHOLOGICALEVALUATIONSAT.!3! 3ANTY ;= HAS COMPARED THE RESULTS OF A COMMONLY USED PSYCHOMETRIC TEST THE --0) AMONGTHEASTRONAUTSANDOTHERCONTROLGROUPS4HISPERSONALITYTESTCONSISTS OFQUESTIONSFORWHICHASUBJECTISASKEDTORESPONDTRUEORFALSE4HISTESTISUSED TOIDENTIFYPSYCHIATRICDISORDERS)TALSOINCLUDESVALIDITYSCALESTODETECTIFTHEAPPLI CANT WAS HONEST IN ANSWERING THE QUESTIONS 4ABLE   7HAT IS REMARKABLE IS THE SIMILARITYOFALLFOURGROUPSOFAPPLICANTS-ERCURY 'EMINI !POLLO ANDSHUTTLE OVER THEYEARS&IGURE  !LL GROUPS ARE EXTREMELY DEFENSIVE AND PRESENT THEMSELVES IN THE BEST POSSIBLE LIGHT ,&+ SCALES  4HE LOW 3I SOCIAL INTROVERSION SCALES IN ALL GROUPS AND THE



&UNDAMENTALSOF3PACE-EDICINE

Figure 6.9. MMPI Profiles of Applicants to the Mercury, Gemini, Apollo, and Early Space Shuttle Astronaut Corps. (Adapted from Santy [1994]).

Figure 6.10. MMPI Profiles of U.S. Male Applicants to the Space Shuttle Astronaut Corps Compared with the Normal U.S. Male Population. (Adapted from Santy [1994]).

C OMPARISONWITHTHENORMALPOPULATION&IGURE SUGGESTTHATAPPLICANTSAREMUCH MORESOCIALLYEXTROVERTEDTHANTHENORMALPOPULATION )NTERESTINGLY ENOUGH NON 53 ASTRONAUTS SHOW A SIMILAR PERSONALITY PROʄLE &IGURE  EVEN THOUGH THE --0) SCORES OF THE GENERAL POPULATION IN VARIOUS COUNTRIESVARYDUETOCULTURALDIFFERENCES &EMALESHUTTLEAPPLICANTSAREALSOMUCHMORELIKETHEIRMALECOUNTERPARTSTHANLIKE THENORMALFEMALEPOPULATION&IGURE /NTHEOTHERHAND THE,&+SCALESOF2USSIAN COSMONAUTSSUGGESTTHATTHEYAREMOREINCLINEDTOEXPRESSTHEIREMOTIONS&IGURE 

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



Figure 6.11. MMPI Profiles of U.S. Male Applicants to the Space Shuttle Astronaut Corps Compared with Japanese Male Applicants. (Adapted from Santy [1994]).

Figure 6.12. MMPI Profiles of U.S. Female Applicants to the Space Shuttle Astronaut Corps Compared with the Normal U.S. Female Population. (Adapted from Santy [1994]).

!LTHOUGHPSYCHOMETRICTESTSAREUSEDTOIDENTIFYPSYCHOPATHOLOGYANDSELECTOUT CANDIDATES THEY ALSO SUGGEST BOTH COMMONALTIES IN PERSONALITY TRAITS AND SOCIO CULTURALDIFFERENCES4HESECOMMONALTIESANDDIFFERENCESWILLULTIMATELYCONTRIBUTETO THEPSYCHOLOGICALANDSOCIOLOGICALPROBLEMSTHATWILLDEVELOPDURINGASPACEMISSION AMONGAGROUPOFHIGHLYSELECTEDINDIVIDUALS



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Figure 6.13. SMIL Profiles of USSR Cosmonaut Candidates. The SMIL Test Is Similar to the MMPI Test, Although the Scales Have Been Redefined. The Numbers in the SMIL Scales Roughly Correspond to the Pathology Described in Table .3 for the MMPI. (Adapted from Santy [1994]).

!PSYCHIATRICEXAMINATIONPERSEISNOTPARTICULARLYHELPFULINDETERMININGWHICH APPLICANTSTOACTUALLYSELECT4HISISDONETHOUGHTHECHARACTERIZATIONOFTHOSEPERSON ALITYTRAITSTHATARETHEMOSTADEQUATEFORAMISSION ANDTHROUGHTHEVALIDATIONOFTHESE CRITERIABYSUBSEQUENTBEHAVIORANALYSISANDPERFORMANCEDURINGTRAININGANDSPACE MISSIONS4HISASPECTWILLBEDEVELOPEDINTHE3ECTION(OWEVER BECAUSETODAYȀS SPACE MISSIONS ARE COMPOSED OF MORE THAN ONE SINGLE INDIVIDUAL LETȀS REVIEW THE SOCIALANDCULTURALISSUESOFGROUPINTERACTIONANDTHEPROCESSOFCREWSELECTION

 #REWSELECTION  3OCIOLOGICALISSUES 4HEREAREMANYVARIABLESTHATCANAFFECTTHECOHESIVENESSANDPERFORMANCEOFAGROUP CULTURE LEADERSHIP GENDER AGE PERSONALATTRACTIVENESS EMOTIONALSTABILITY COMPE TENCE COOPERATIVENESS ANDSOCIALVERSATILITY;#ONNORSETAL =)TISIMPORTANTTO NOTE HERE THAT THESE STUDIES WERE CONDUCTED IN ANALOG ENVIRONMENTS WITH CONTROL GROUPS ANDTHATMOSTOFSUBJECTSAREFROM7ESTERNCULTURE  #ONʄNEMENTANDPERSONALSPACE 'ROUND BASEDSTUDIESHAVEDETERMINEDTHATPSYCHOLOGICALIMPAIRMENTSTARTEDTOOCCUR WHENTHEAVAILABLEVOLUMEWASRESTRICTEDTOMPERPERSONFORORDAYSOF CONʄNEMENT MPERPERSONFORORMONTHS ANDMPERPERSONFORMORE THANMONTHS;&RASER =)NTERESTINGLY EXCEPTFORSPACESTATIONS THEHABITABLE PRESSURIZEDVOLUMEINMOSTSPACECRAFTISLESSTHANTHESEVALUES4ABLE 

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT Table 6.6.



Habitable Pressurized Volume (in m3) in Past and Present Spacecraft.

Spacecraft

Cabin Volume

Crew

Volume Per Person

Mercury

1.53

1

1.53

Gemini

2.52

2



Apollo

9.1

3

3.0

Soyuz

10.2

2

5.1

Shuttle

74.3

7



Salyut

99

3

33.0

Skylab



3

120.3

Mir



3



ISS

1,200



200

4HENUMBEROFINDIVIDUALSSHARINGCONʄNEMENTISBELIEVEDTOBEANOTHERIMPORTANT VARIABLEAFFECTINGTHEAMOUNTOFSPACENEEDEDPERINDIVIDUAL-ORESPACEPERINDI VIDUALISNEEDEDASTHENUMBEROFINDIVIDUALSINCREASES;3MITHAND(AYTHORN = (OWEVER CONʄNEDINDIVIDUALSTENDTOPLACEHEAVYEMPHASISONASSIGNEDWORKAND LITTLEEMPHASISONRECREATIONALOPPORTUNITIES7HENRECREATIONISSOUGHT ITTENDSTOBE PASSIVEINNATURE4HISMIGHTACCOUNTFORTHEFACTTHATASTRONAUTSANDCOSMONAUTSARE NOTPURSUINGEXERCISEPROGRAMSENTHUSIASTICALLY TOSAYTHELEAST 7HENTWOPEOPLEARETALKINGTOEACHOTHER THEYTENDTOSTANDASPECIʄCDISTANCE APART%ACHPERSONHASANINVISIBLEBOUNDARYAROUNDHISHERBODYINTOWHICHOTHER PEOPLEMAYNOTENTER&IGURE )FSOMEONEPENETRATESTHISBOUNDARY THEȃINVADEDȄ PERSONWILLFEELUNCOMFORTABLEANDMOVEAWAYTOINCREASEHISORHERDISTANCEFROMTHE ȃINVADERȄ4HEMAJOREXCEPTIONISFAMILYMEMBERSANDOTHERLOVEDONES4HISPER SONALDISTANCEISNOTDUETOBODYODORORBADBREATH#LOSENESSLENDSASENSEOFINTI MACY THEDEGREEOFWHICHVARIESWITHTHEDISTANCEBETWEENINDIVIDUALS 4HE AVERAGE PERSONAL DISTANCE VARIES FROM CULTURE TO CULTURE ,ATIN !MERICANS &RENCHAND!RABSINTERACTATCLOSERDISTANCESTHAN53 %NGLISH 3WEDISH OR'ERMAN INDIVIDUALS ;(ALL = $URING TWO SUMMER SESSIONS OF THE )NTERNATIONAL 3PACE 5NIVERSITY STUDENTS FROM THE 3PACE ,IFE 3CIENCES $EPARTMENT PERFORMED A STUDY ATTEMPTINGTODETERMINETHEPERSONALSPACEOFSTUDENTSFROMVARIOUSCOUNTRIES;"UI AND7ONG =$URINGAFAKEINTERVIEW THEDISTANCEANDTHEANGLEBETWEENTHE SUBJECTSANDTHEINTERVIEWERWEREMEASURED2ESULTSINDICATEDTHATTHISDISTANCEVARIED FROMCMIN!SIANEG *APANESE STUDENTS TOCMORLESSIN,ATINEG )TALIAN STUDENTS4HEREWASALSOASTRONGTENDENCYTONOTDIRECTLYFACETHEINTERVIEWER BUT STAYATANANGLE4HISANGLESEEMEDALSOSTRONGLYCORRELATEDWITHTHESUBJECTȀSCULTURAL ORIGIN&IGURE  4HEUSEOFPHYSICALOREYECONTACTALSOVARIESBYCULTURE!LTHOUGHINSOMECUL TURES EYECONTACTISAWAYTOCOMMUNICATE INOTHERCULTURESPHYSICALOREYECONTACT MAYLEADTODISCOMFORTANDMAYEVENCARRYSEXUALOVERTONES 3OMEASTRONAUTSHAVEREPORTEDTHATTHESWOLLENFACEINWEIGHTLESSNESS DUETOTHEHEADWARDʅUIDSHIFT CREATESAPROBLEMINCOMMUNICATINGBYEYECONTACT





&UNDAMENTALSOF3PACE-EDICINE

Figure 6.14. Each Person Has an Invisible Boundary Around His/Her Body into Which Other People May Not Come. (Source Unknown).

Figure 6.15. Mean Distance and Angle Between Two Individuals During a Seated Interview. Catherine Beaulieu, Julielynn Wong, and Linh Bui Compiled These Results During the ISU 2002 Summer Session Program, on a Population of 23 Students from 13 Different Countries.

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



7HEN COMPARING THE REQUIRED PERSONAL DISTANCE IN VARIOUS ENVIRONMENTAL C ONDITIONS ITWASFOUNDTHATGREATERDISTANCESAREREQUIREDFORPERSONALSPACEA IN SMALL ROOMS VERSUS LARGE ROOMS B INSIDE LOCATIONS VERSUS OUTSIDE LOCATIONS C IN HIGH ANXIETYSETTINGSVERSUSINLOW ANXIETYSETTINGSANDD WITHPEOPLEWITHWHOM YOU EXPECT TO BE INTERACTING OVER A LONG PERIOD OF TIME VERSUS A SHORT INTERACTION ;"ISHOP =)NTERESTINGLY ALLTHESEFACTORSSMALLROOMS INSIDE HIGHANXIETYSETTING LONGINTERACTION AREPRESENTDURINGSPACEMISSIONS#ONSEQUENTLY THEPERSONALDISTANCE OFTHEASTRONAUTSSHOULDINCREASEINTHECONDITIONSOFASPACEMISSION)TWOULDBEINTER ESTINGTOACTUALLYMEASURETHEPERSONALDISTANCESOFCREWMEMBERSONBOARDTHE)33AND COMPAREFOREXAMPLETHESEDISTANCESBETWEENASTRONAUTSANDCOSMONAUTS /NTHEOTHERHAND THEDIMENSIONSOFASPACECRAFTARENECESSARILYSMALL ANDTHERE ISLITTLETONOPRIVACY&IGURE 'ROUND BASEDSTUDIESINDICATETHATPRIVACYONLY SEEMSTOALLEVIATEANXIETYANDSTRESSINSHORT DURATIONMISSIONS)NLONG DURATIONMIS SIONSWITHPRIVACY ITWASNOTEDTHATEVENWITHACCESSTOANOTHERPERSONINTHEGROUP FORCONVERSATIONANDSOCIALINTERACTION STRESSLEVELSAREHIGHER;4AYLORETAL = 4HISALSOSEEMSTOBETRUEFORSPACEMISSIONS)NDEED ISSUESOFPERSONALHYGIENEAND HOUSEKEEPINGALONEACCOUNTFORABOUTOFINCIDENTSDURINGSPACEMISSIONSWITH 53ONLYCREWS;3ANTY =&IGURE  )TISWELLKNOWNTHATUNDERCROWDEDCONDITIONS MENANDWOMENREACTDIFFERENTLY 7OMENTENDTOPERCEIVESMALL CROWDEDPLACESASFRIENDLYANDSOCIABLE WHILEMEN TENDTORESPONDTOSUCHENVIRONMENTSASIRRITATINGANDUNCOMFORTABLE-ENAREMORE LIKELYTOFEELTHEIRPERSONALSPACEVIOLATEDINCROWDEDPLACESANDPERCEIVEACONTINU INGCHALLENGETOPATTERNSOFMALEDOMINANCE4HUS MENRESPONDWITHGREATERIRRITA TIONANDHOSTILITYTOCROWDEDCONDITIONSTHANDOWOMEN4HEINTERESTINGNOTEISTHAT MIXED GENDERGROUPSTENDTORESPONDNEARLYASWELLTOCROWDEDCIRCUMSTANCESASDO GROUPSOFWOMENONLY;"ISHOP =

Figure 6.16. Two Astronauts Looking at Earth from the Observatory Windows of the Space Shuttle. (Credit NASA).



&UNDAMENTALSOF3PACE-EDICINE

Figure 6.17. NASA Astronaut Douglas H. Wheelock Rides His Vacuum Cleaner Doing Housekeeping Chores in the ISS Destiny Lab. (Credit NASA).

 -IXEDGENDERISSUES 7OMENHAVEPERFORMEDEQUALLYORSUPERIORTOMALECOUNTERPARTSIN!NTARCTICSTATIONS ANDUNDERWATERHABITATSTUDIES;#ONNORSETAL =4HOUGHTHEREISLITTLEQUESTION ABOUTTHECOMPETENCEOFWOMENTOHANDLESPACEMISSIONS THETOTALNUMBEROFFEMALE ASTRONAUTSANDCOSMONAUTSREPRESENTSLESSTHANTHATOFMALEASTRONAUTS(OPEFULLY THEINCREASINGNUMBEROFWOMENASTRONAUTSWILLTRANSLATEINTOALARGEPARTICIPATIONIN THE)33ANDINTERPLANETARYMISSIONS(OWEVER FACTORSASSOCIATEDWITHLONG DURATION MISSIONSMAYBEAFFECTEDBYTHEPRESENCEOFWOMENONBOARD !NTARCTIC EXPEDITIONS STARTED INCLUDING WOMEN IN  BUT MANY STATIONS STILL REFUSETOALLOWWOMENTOWINTER OVER.EVERTHELESS THERESULTSOFSTUDIESINANALOGS SUGGESTTHATTHEPRESENCEOFWOMENEXERTSAPOSITIVEINʅUENCEANDDISCOURAGESCERTAIN BEHAVIORS THAT COULD LEAD TO INJURY OR GROUP CONʅICT LIKE DRINKING AND ʄGHTING ;0ALINKAS =(OWEVER OTHERSTUDIESFOUNDTHATTHEINTRODUCTIONOFAFEMALEINTO AMALEGROUPCAUSEDDESTABILIZINGEFFECTS;(ARRISONAND#ONNORS = 7ITH THE INCREASING DURATION OF FUTURE MISSIONS SEXUAL TENSIONS AND PREJUDICES MAYBEFORCEDTOTHESURFACECREATINGFRICTIONANDTHISCOULDIMPACTBOTHCREWCOHE SIVENESSANDPERFORMANCE4HECONCERNABOUTANAFFAIROCCURRINGONBOARDTHE)33IS PROBABLYUNWARRANTED%VENIFITWERETOHAPPEN THEQUESTIONWILLBEWHATEFFECT IF ANY THISNEWLEVELOFINTERACTIONWILLHAVEONTHEPERFORMANCEOFTHECREW(ELMREICH ETAL;=CONSIDERTHATMOREHARMTHANGOODCANCOMEOUTOFAPOLICYTHATREGULATES THEMORALCONDUCTOFTHESPACESTATIONCREW3UCHAPOLICYWILLNOTMAKESEXUALDESIRE GOAWAY ONLYPERHAPSFRUSTRATEITINTOANOTHER MOREDANGEROUSFORM(ESUGGESTSTHAT THESPACEAGENCIESSHOULDTAKEAȃHANDSOFFȄAPPROACHNOPUNINTENDED
TOTHISISSUE ANDSEEWHATHAPPENS 'ENDERSTEREOTYPINGBYMEMBERSOFTHECREWCANALSOHAVEADESTABILIZINGEFFECT 4HEREISSOMEEVIDENCETHATMALEASTRONAUTSANDCOSMONAUTS;/BERG =STILLHOLD ON TO OUTMODED VIEWS OF WOMEN 4HESE STEREOTYPES SHOULD BE AVOIDED BY HAVING CREWMEMBERSWORKTOGETHERONPROJECTSBEFOREASPACEMISSIONTODEMONSTRATEEACH CREWMEMBERȀS NOTJUSTTHEWOMENȀS COMPETENCEANDTECHNICALPROʄCIENCY

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



 -ULTI CULTURALISSUES 4ODAY THE )33 AND TOMORROW THE EXPLORATORY MISSIONS PRESENT THE OPPORTUNITY TO HAVEGREATERREPRESENTATIONOFDIFFERENTNATIONALITIESINSPACE4HISWILLBRINGPROB LEMSTHATWERENOTPRESENTINTHEMOREHOMOGENOUSMISSIONS WHICHHAVEOCCURREDUP TONOW4HESPACESHUTTLEHASHADINTERNATIONALCREWSANDWOMENCREWMEMBERSONA SOMEWHATREGULARBASIS&IGURE BUTTHESHORTDURATIONOFTHESEMISSIONSCANNOT COMPARETOTHELONG DURATIONMISSIONSWEWILLBEFACINGINTHEFUTURE #ULTUREREFERSTOWIDELYSHAREDBELIEFS EXPECTANCIESANDBEHAVIOROFMEMBERSOFA GROUPONANORGANIZATIONAL PROFESSIONALORNATIONALLEVEL"ESIDESPERSONALSPACEAS ALREADYDESCRIBED STUDIESONPILOTPOPULATIONSHAVESHOWNSIGNIʄCANTNATIONALDIFFER ENCESINATTITUDES SUCHASACCEPTANCEOFHIERARCHICALLEADERSHIPANDTHENECESSITYOF ADHERING TO RULES AND PROCEDURES !NOTHER WELL KNOWN CULTURAL DIFFERENCE IS TIME PERCEPTIONFOREXAMPLE !NGLO 3AXONSTYPICALLYEMPHASIZESCHEDULES APPOINTMENTS SEGMENTATION AND PROMPTNESS WHEREAS -IDDLE %AST AND ,ATIN CULTURES ARE MORE ʅEXIBLEANDFEELMOREATEASEWITHSEVERALTHINGSGOINGONATONCE3UCHDIFFERENCES OBVIOUSLYHAVETHEPOTENTIALTOCAUSEPROBLEMSINSAFETY PERFORMANCE ANDINTERACTION BETWEENCREWMEMBERS 4HELESSONSLEARNEDFROMTHE.!3! -IRPROGRAMWITHMULTI CULTURALCREWSILLUS TRATETHEDIFʄCULTIESTHATCANBEENCOUNTERED3EVERAL53ASTRONAUTSHAVECOMMENTED THATUNDERCONDITIONSOFHIGHSTRESSSUCHASDURINGLONG DURATIONMISSIONS CULTURAL DIFFERENCESDISRUPTEDTHEHARMONYAMONGTHECREW4HEYSUFFEREDFROMTHEFACTSTHAT A THELANGUAGEDIFFERENCESLEDTOMISUNDERSTANDINGSB THEYWERETHESOLEMEMBERS OFACULTURALGROUPC THEYHADPROLONGEDPERIODSOFNOCONTACTWITH%NGLISH SPEAKERS EVENLESSWITHFAMILYD THEYHADVERYRESTRICTEDFOODSELECTIONANDE THEYWERE

Figure 6.18. The Crew of Shuttle STS-51G (June 1985) Included Astronauts from the United States, France, and Saudi Arabia, Both Male and Female, with Military or Civilian Background. (Credit NASA).

&UNDAMENTALSOF3PACE-EDICINE



NOTALLOWEDTOOPERATEEQUIPMENT3OMEALSOCOMPLAINEDTHEYWERETREATEDASAGUEST RATHERTHANAWORKINGCREWMEMBER;"URROUGH = #AMPBELL;= INAREVIEWOFCULTURALINTEGRATIONLITERATURE IDENTIʄEDATHREE STAGETHEORYOFADJUSTMENTTOANEWCULTURECALLEDTHE5 CURVETHEORY4HEʄRSTSTAGE OFTHISTHEORYISENTRY)NTHISSTAGETHENOVELTYOFTHEENVIRONMENTPRECLUDESADJUST MENTPROBLEMSFROMMANIFESTINGTHEMSELVES4HESECONDSTAGEISADJUSTMENT)NTHIS STAGETHEINDIVIDUALLEARNSNEWWAYSOFTHINKINGANDACTING ANDFRUSTRATIONWITHTHE ENVIRONMENT IS HIGH 4HE THIRD STAGE IS ADAPTATION 4HIS STAGE SEES THE INDIVIDUALS RECONCILETHEIREXPECTATIONSWITHTHEREALITYOFTHESITUATION )TISEXPECTEDTHATTHEADJUSTMENTOFASTRONAUTSTOTHECULTUREOFALONG DURATION CREWWILLBESIMILAR4HEINITIALAWEOFBEINGINSPACEWILLGIVEWAYTOCULTURALREAC TIONS WHICHMAYINCLUDEDIFʄCULTIESINUNDERSTANDINGNON VERBALCUES DIFʄCULTIESIN ADJUSTINGTONEWWORKREGIMES ANDTECHNICALLANGUAGEDIFʄCULTIES&ORTHISREASON TRAININGINEACHOTHERȀSCULTUREANDLIFESTYLEISANESSENTIALPARTOFANYLONG DURATION INTERNATIONALSPACEEFFORT 

3ELECTIONISSUES

#REWS ARE IN FACT SMALL SOCIAL SYSTEMS SHAPED BY MULTIPLE DETERMINANTS NONE OF WHICH CONSIDEREDINISOLATION CANNECESSARILYACCOUNTFORTHEVARIATIONSINBEHAVIORAL INTERACTIONSORPERFORMANCEEFFECTIVENESS 2EVIEWSOFTHELITERATUREON!NTARCTICAEXPEDITIONSFOCUSINGONTHEIRRELEVANCETO LONG DURATIONSPACEʅIGHTHAVEIDENTIʄEDTHELEADERASTHESINGLEMOSTIMPORTANTROLE INTHEISOLATEDGROUP;3TUSTER =,EADERSORGANIZE DIRECT ANDCOORDINATEFOLLOW ERS 4HEY ALSO EXERT THEIR INʅUENCE TO A HELP THE GROUP MAINTAIN HARMONY AND STABILITYB INTERPRETTHECONDITIONSTHATCONFRONTITC SETGOALSANDD MEETCHAL LENGESPOSEDFROMOUTSIDE4HEMOSTEFFECTIVELEADERLETCREWSDOWORKWITHMINIMAL INTERFERENCE BUTRECOGNIZEWHENGROUPACTIVITYISNEEDEDANDARRANGETHATACTIVITY 'OODLEADERSAREALSOABLETOSWINGBETWEENAUTOCRATIC THATISMAKINGDECISIONSWITH OUTSOLICITINGSUBORDINATEȀSINPUTS ANDPARTICIPATIVE DEMOCRATICSTYLESOFLEADERSHIP ASNEEDED0RESCRIPTIONSFORGOODLEADERSHIPOFTENDWELLUPONTHESELECTIONANDTRAIN ING OF LEADERS (OWEVER SUCH PRESCRIPTIONS COULD ALSO INVOLVE THE SELECTION AND TRAININGOFFOLLOWERS ANDTHESTRUCTURINGOFTHESOCIALSETTINGSANDTHEGROUPȀSTASKS /NEPOTENTIALSOURCEOFCONʅICTINTODAYȀSSPACEMISSIONS ASITISFORANALOGS IS THATTHELEADERȀSRIGHTTOEXERTHISHERINʅUENCEISCONFERREDTHROUGHAPPOINTMENTBYA HIGHERAUTHORITY NOTBYTHEGROUPITSELF4OCOUNTER BALANCETHIS ANOTHERKEYFACTOROF LONG DURATION MISSIONS IS TO HAVE OPEN COMMUNICATION AMONG THE CREW AND ALLOW FEEDBACKCHANNELS#OMMUNICATIONISESSENTIALFORITPROVIDESUPDATEDKNOWLEDGEOF OTHER PEOPLEȀS ATTITUDES AND VIEWS WHICH IS NECESSARY FOR SOCIAL COMPARISON PRO CESSESANDFORCONʅICTMANAGEMENT!LSO ASISEVIDENTFROMTHE)3%-3)EXPERIMENT MISCOMMUNICATION CAN CONTRIBUTE TO INTERPERSONAL FRICTION AND CONʅICT WITHIN THE CREWORBETWEENTHECREWANDTHEGROUNDPERSONNEL !NOTHER FACTOR IS TO HAVE CLEARLY DEʄNED CONTINGENCIES FOR ACHIEVING GOALS 2ESEARCHʄNDINGSAREUNAMBIGUOUSINSHOWINGTHATACLEAR ENGAGINGSETOFOBJECTIVES ISAPOWERFULMEANSFORORIENTINGMEMBERSTOWARDACHIEVINGOVERALLORGANIZATIONAL GOALS'ROUPGOALSENCOURAGEPEOPLETOCOORDINATETHEIRACTIVITIESFORMUTUALGAIN AND HENCEARELIKELYTOAFFECTTHETONEOFINTERPERSONALRELATIONSWITHINTHEGROUP(OWEVER

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



CREWMEMBERS MUST FEEL PERSONALLY COMMITTED TO THESE GOALS IT WILL NOT SUFʄCE TO SIMPLYIMPOSETHEMFROMABOVE)NADDITION FORLONG DURATIONMISSIONS MEANSMUST BEFOUNDTOMAINTAINASTRONAUTSȀINTERESTINDISTANTGOALSOVERPROLONGEDPERIODSOF TIME)TMAYTHUSBEDESIRABLETOESTABLISHANUMBEROFINTERIMGOALS WHICHCANBE PURSUEDANDSAVORED &INALLY GROUPSOFMORETHANTWOMUSTHAVEBOUNDARYROLEPERSONSWHOACTTOINTER PRETINTERESTSANDCONCERNSOFALLSIDESTOALLOWACTIVITYTOPROGRESSSMOOTHLY"OUNDARY ROLEPERSONSSERVEASAGENTSFORPURPOSESOFBARGAININGANDNEGOTIATION4HESEBOUND ARY PERSONS WITH THE HELP OF THE LEADER SEE ABOVE AND THE AUTHORITY IN -ISSION #ONTROL SHOULDMANAGETHEINEVITABLEPROBLEMSANDDISPUTESTHATOCCURINREALTIME ANDTHATTHREATENTHEOVERALLINTEGRITYOFTHEGROUP ANDARRANGECOOPERATIVEVENTURES WITHEQUITABLEOUTCOMESFORBOTHSIDES;#ONNORSETAL =  #OMPATIBILITY )NTHECONTEXTOFMULTINATIONALMISSIONS ONEOFTHEMOREIMPORTANTCHALLENGESISTO ENSURE THAT THE INDIVIDUALS ARE COMPATIBLE AND CAN WORK TOGETHER EFFECTIVELY #REWMEMBERSMAYBECONSIDEREDCOMPATIBLEINTHATEACHMEMBERDEMONSTRATESQUAL ITIESANDBEHAVIORSTHATOTHERCREWMEMBERSCONSIDERDESIRABLEANDAPPROPRIATE4HIS ISCHALLENGINGINTHESPACEPROGRAMBECAUSEINDIVIDUALSMAYHAVEVERYDIFFERENTEDU CATIONALBACKGROUNDS&OREXAMPLE SCIENTISTSPREFERTHEIRAUTONOMYANDTENDTONOT INTERACTANDNOTTOWORKWELLINAHIERARCHICALCOMMANDSTRUCTURE/NTHEOTHERHAND PILOT ASTRONAUTSOFTENHAVEMILITARYBACKGROUNDS WHICHLEADTHEMTOPREFERAMORE ORDEREDCOMMANDSTRUCTURE %VALUATIONOFCOMPATIBILITYMIGHTBEBASEDONTHERESULTSFROMPSYCHOLOGICALPER FORMANCE TESTS AND PERSONALITY QUESTIONNAIRES !NOTHER MORE BEHAVIOR ORIENTED APPROACH WHICHHASBEENDEVELOPEDINTHECONTEXTOFINDUSTRIALAPPLICATIONS INCLUDES THE COMBINATION OF A VARIETY OF BEHAVIORAL EXERCISES LIKE ROLE PLAYS GROUP DISCUS SIONS AND GROUP EXERCISES 4HE OBJECTIVE IS TO SELECT INDIVIDUALS WHO DEMONSTRATE CAPABILITIESFOREFFECTIVETEAMFUNCTIONINGANDPROBLEMSOLVING&IGURE  4HE3OVIET2USSIANSPACEPROGRAMHASSPENTCONSIDERABLEEFFORTDEVELOPINGMETH ODSTOASSESSINTERPERSONALCOMPATIBILITYFORLONG DURATIONMISSIONS4HESEMETHODS INCLUDEATTITUDEASSESSMENTS PSYCHO PHYSIOLOGICALTESTS ANDSPECIʄCGROUPEXERCISES 4HE 2USSIAN PSYCHOLOGISTS BELIEVE THAT BIORHYTHMS ARE USEFUL IN SELECTING SPECIʄC COSMONAUTS FOR SPACE MISSIONS &OR EXAMPLE WHEN THE CREW WORKS TOGETHER ON A COMPLEXTASKDURINGATRAININGSESSION THEYMONITORTHEIRPULSE!SSOONASTHECREW MEMBERSSTARTHELPINGEACHOTHERTHEIRPULSESSYNCHRONIZETOSOMEEXTENT)TISBELIEVED THATTHEHIGHERTHEBIORHYTHMICITY THEGREATERTHECOMPATIBILITY;"LUTHAND(ELPIE = CITEDBY3ANTY =(OWEVER THESECOMPATIBILITYTESTSHAVENOTBEENVALIDATED  #REWCOMPOSITION /BVIOUSLY THELARGERTHEGROUP THEMORECHANCESOFINTERPERSONALCONʅICT)NFACT IT WASFOUNDTHATLARGERGROUPSREACTBETTERTOCONʄNEMENTSITUATIONS)RRITATIONSINTHESE GROUPSARENOTDIRECTEDATOTHERGROUPMEMBERSBUTATȃTHINGSORNON PERSONALASPECTS OFTHESITUATIONȄ;3MITHAND(AYTHORN =/BVIOUSLY FORSPACEMISSIONS ESPE CIALLY INTERPLANETARY THE ULTIMATE DECISION WILL BE MADE UPON PROPULSION CONSIDER ATIONSAFTERCALCULATINGTHETOTALWEIGHTNEEDEDINTERMSOFLIFESUPPORTSYSTEMMASS



&UNDAMENTALSOF3PACE-EDICINE

Figure 6.19. Individuals May Find Themselves Isolated as a Result of Poor Leadership or Not Fitting into the Group. (Source Unknown).

PERPERSON(OWEVER ONERULEOFTHUMBISTHATCREWSIZEANDHETEROGENEITYMUSTBEAS SMALLASPOSSIBLE BECAUSETHECOMPLEXITYOFINTERPERSONALINTERACTIONINCREASESWITH CREW SIZE AND HETEROGENEITY /N THE OTHER HAND INCREASING CREW SIZE INCREASES THE NUMBEROFPOSSIBLESOCIALRELATIONSHIPSAND AMONGOTHERTHINGS OPTIONSFORSOCIAL STIMULATIONANDDEVELOPINGFRIENDSHIPS WHICHAREFAVORABLEFACTORSFORGROUPCOHE SIVENESS!NODDNUMBEROFCREWMEMBERSISRECOMMENDEDOVERANEVENNUMBERTO PREVENT THE DEVELOPMENT OF TWO EQUALIZED GROUPS WHICH MIGHT HINDER DEMOCRATIC PROBLEMSOLVING ! VERY IMPORTANT CONSIDERATION IS RELATED TO THE OCCUPATIONAL ROLE OF THE CREW 4RADITIONALLY ALLCREWSINHUMANSPACEEXPLORATIONHAVEINCLUDEDONEORMOREPILOTS 3OMEOFTHEDESIGNERSOFHUMANMISSIONS;:UBRIN =STATETHATGIVENTHEDEMON STRATEDABILITYOFGUIDINGUNMANNEDSPACECRAFTSAFELYTOTHESURFACEOF-ARS TAKINGA PILOTWOULDBEANUNNECESSARYWASTEOFRESOURCES4HEYARGUETHATASCIENTISTTRAINED MINIMALLYTOOVERRIDETHEAUTOMATICSYSTEMINCASEOFMALFUNCTIONWOULDBEENOUGH !LLSCHOOLSOFTHOUGHTCONSIDERITESSENTIALTOTAKEALONGAMEDICALDOCTORTOCOPEWITH MEDICALPROBLEMSDURINGTHETRIP3HOULDAMECHANICBEINCLUDEDINTHEMISSIONTO REPAIRMALFUNCTIONINGSYSTEMS(OWMANYSCIENTISTSARENECESSARYDURINGAPIONEER EXPLORATORYMISSION/RSHOULDJUSTEXTREMELYʄTINDIVIDUALSINTEGRATETHECREWON THISOCCASION /NESURETHINGISTHATTHEROLEOFMISSIONCOMMANDERSHOULDBELONGTOTHEMOSTQUALI ʄEDINDIVIDUALINTHECREW WHETHERAPILOT ENGINEERORSCIENTIST THATISONEWHOSELEAD ERSHIPSTYLEENCOURAGESGROUPDYNAMICS GROUPPERFORMANCE ANDMORALE#ONSEQUENTLY THEROLEOFMISSIONCOMMANDERWILLNOTAUTOMATICALLYFALLONAPILOT ASITHASBEENTHE CASEFORALLSPACEMISSIONSSOFAR WITHTHEEXCEPTIONOFACOUPLEOF)33INCREMENTS

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



/FPRIMEIMPORTANCEARETHEMOTIVATIONALISSUESRAISEDBYTHEPROSPECTOFLONG DURATIONSPACEOCCUPANCY-OTIVATIONPLAYSACRITICALROLEINMAINTAININGINDIVIDUAL PERFORMANCES AND AMICABLE SOCIAL INTERACTIONS OVER EXTENDED INTERVALS OF ISOLATION AND CONʄNEMENT $URATION AND EXPECTED DURATION OF MISSIONS ALSO SEEM TO BE AN IMPORTANTVARIABLETOCONSIDER4AYLORETAL;=FOUNDTHATWHENAGROUPEXPECTSA LONG DURATION MISSION THERE IS MORE STRESS EVIDENT THAN A GROUP EXPECTING A SHORT DURATIONMISSION &ORCOLLECTIVEOPERATIONS THERIGHTPEOPLE WELLTRAINEDANDPROPERLYCONʄGUREDTHAT IS WITHTHERIGHTMIXOFSKILLS PERSONALCHARACTERISTICS TASKREQUIREMENTS ANDWORKSET TING AREESSENTIAL(OWEVER THISWILLULTIMATELYBRINGDIFFERENCESINEDUCATION CULTURE ANDAGE WHICHMAYALSOCONTRIBUTETOISSUESINGROUPCOHESIVENESSANDPERFORMANCE %VENTHOUGHTHEREHASBEENASIGNIʄCANTADVANCEOFWOMENASTRONAUTSLATELY INCLUD INGSEVERALFEMALESHUTTLEPILOTS AGAININGENERALALLCREWSHAVEBEENPREDOMINANTLY MALE ,ONG DURATION INTERPLANETARY MISSIONS RAISE UNIQUE CONSIDERATIONS (AVING AN ALL MALECREWFORSUCHALONGTIMEISATLEASTDOUBTFUL-ARRIEDCOUPLESAREDEʄNITELYA POSSIBILITY ANDMIXEDCREWSWITHNON MARRIEDMEMBERSAREALSOBEINGCONSIDERED"UT WHATIFTWOCREWMEMBERSFALLINLOVEWITHEACHOTHERORALTERCATEDUETOTHEIRRELATION SHIP7HATABOUTTHEOTHERCREWMEMBERSTHATAREȃLEFTOUTȄ-ENAREBELIEVEDTOBE PHYSICALLYSTRONGER BUTONTHEOTHERHANDWOMENAREMORERESILIENTPSYCHOLOGICALLY 4HEFACTTHATTHEREISNOQUICKWAYTOGETTHECREWBACKADDSTOTHENEEDTOCONSIDERALL POSSIBLEALTERNATIVES%XPERIMENTSAIMEDATTHEUNDERSTANDINGOFTHEPSYCHOLOGICALAND SOCIALCONSEQUENCESOFSEXUALITYANDMIXED GENDERGROUPSAREALSONEEDED  %XTERNALFACTORS )T IS INTERESTING TO NOTE THAT THERE ARE MANY KNOWN FACTORS THAT CONTRIBUTE TO GROUP COHESIONANDPERFORMANCEORTOGROUPʄSSION4ABLE &OREXAMPLE DURINGLONG DURATIONMISSIONSONBOARD-IR SEVERALCREWMEMBERSREPORTEDTHATTHEARRIVALOFAN INTERNATIONAL VISITING CREW STAYING IN THE STATION FOR A PERIOD OF  WEEK HELPED TO NEUTRALIZETENSIONSAMONGTHECREW#OSMONAUTSONEXTENDEDʅIGHTSHADLETTERSAND Table 6.7.

Factors that Impact Group Fusion and Group Fission.

Factors that Impact Group Fusion

Factors that Impact Group Fission

s %MERGENCIESWHENPEOPLEAREFORCEDTO s 0OWERANDSTATUSEG LEADERFOLLOWERS work together for common survival s $IFFERENCESINWORKDEMANDSEG SHIFTS s !RRIVALOFOUTSIDERSEG REPLACEMENTS s $IFFERENCESINRESPONSIBILITYEG PILOTS non-pilots) new personnel) s $IFFERENCESINMOTIVATION s 2ESENTMENTTOWARDSOUTSIDERSEG s $IFFERENCESINPERSONALVALUES mission control, authorities) s ,EADERSHIPEG AUTHORITARIAN s ,EADERSHIPPROMOTESPERFORMANCEAND participative) minimizes conflicts s 3OCIALEVENTSEG SURPRISES PARTIES holidays) s 'ROUPRITUALSANDHABITS



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Figure 6.20. As a Group Ritual, Shuttle Crew-Members Play Poker on the Launch Day. They Leave the Crew Quarters only After the Commander Wins. (Credit Douglas Hamilton).

PRESENTSFROMHOME ALONGWITHSPECIALFOODSANDFRESHMILK DELIVEREDTOTHEMIN SPACE4HEYWEREALSOSURPRISEDBYSMALL BUTAPPARENTLYDELIGHTFULTOYS NOVELTIES ETC4HEUNEXPECTEDUNDOUBTEDLYPLAYSAVERYLARGEROLEINWHATWESEEASTHEFULLNESS OFEXPERIENCE0ARTIESANDGROUPRITUALS&IGURE ALSOHELPMAINTAINMORALEAND GROUPINTERACTION )TISINTERESTINGTONOTETHATLEADERSHIPBELONGSTOBOTHCATEGORIES4HATIS GOODLEAD ERSHIP HELPS GROUP FUSION BUT BAD LEADERSHIP CAN BE AT THE ORIGIN OF GROUP ʄSSION /BVIOUSLY THE ABILITY TO BE A TEAM LEADER OR A TEAM FOLLOWER SHOULD BE PART OF THE ȃSELECT INȄCRITERIA"UTHOWDOWEDEʄNETHESECRITERIAANDOTHERS ANDMOSTIMPOR TANTLY HOWDOWEVALIDATETHEM7EWILLREVIEWTHESEISSUESINTHEFOLLOWINGSECTION

 #REWBEHAVIORANDPERFORMANCE 3OFAR THEPSYCHOLOGICALSELECTIONOFASTRONAUTSHASFOCUSEDONSELECTING OUTCANDIDATES WITH PSYCHOPATHOLOGICAL DISORDERS )N CONTRAST TO THESE WELL ESTABLISHED ȃSELECT OUTȄ CRITERIA ȃSELECT INȄ CRITERIA NEED TO BE DEVELOPED IN RELATION TO SPECIʄC ASPECTS OF THE MISSION SUCHASMISSIONOBJECTIVES MISSIONDURATIONANDCREWCOMPOSITION/NCEDETER MINED THE ȃSELECT INȄ CHARACTERISTICS REQUIRE VALIDATION AGAINST IN ʅIGHT PERFORMANCE MEASURES ANDNEEDTOBEEXPLOREDINAMISSION SPECIʄCMANNER;3ANDALETAL = 4ODATE THEABSENCEOFFORMALCRITERIAFORASTRONAUTPERFORMANCEANDTHELIMITED RESEARCHOPPORTUNITIESHAVEMADEITVERYDIFʄCULTTOEVALUATETHEEFʄCIENCYOFCREW

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



SELECTIONSTRATEGIES3UCHEVALUATIONALSOREQUIRESTHATSELECT INCRITERIAMUSTNOTBE USED IN THE INITIAL SELECTION UNTIL THEY HAVE BEEN FOUND TO PREDICT ASTRONAUT PERFOR MANCE/NEPOTENTIALBIASINVALIDATINGSELECTIONCRITERIAFORASTRONAUTSANDCOSMO NAUTS WHO HAVE ALREADY GONE THROUGH A FORMAL SELECTION PROCESS IS RELATED TO THE RESTRICTIONOFRANGEINPERSONALITYSCORES ASSEENINTHE--0) 4HEBEHAVIORALHEALTHINFORMATIONDERIVEDFROMPSYCHOLOGICALTESTINGEVALUATIONS INTOTHEʄNALSELECTIONPROCESSOFASTRONAUTCANDIDATESSEE#HAPTER 3ECTION ISOFLIMITEDUSEBECAUSETHECANDIDATESHAVENOTYETSUCCESSFULLYCOMPLETEDTHETRAIN INGANDEVALUATIONPERIODPRIORTOBECOMINGANASTRONAUT!DDITIONALLY ITCANTAKEUP TOYEARSFROMTHETIMEASPACEAGENCYHIRESANASTRONAUTCANDIDATETOWHENTHEASTRO NAUT RETURNS FROM HIS OR HER ʄRST LONG DURATION MISSION 4HEREFORE TO DETERMINE WHETHERTHEBEHAVIORALHEALTHINFORMATIONCOLLECTEDDURINGTHEHIRINGPROCESSISUSE FUL THEPERFORMANCEOFTHENEWASTRONAUTSMUSTBEOBSERVEDFORAPERIODSIGNIʄCANTLY LONGERTHANTHEYEARTHATHASELAPSEDSINCETHEIRHIRING !NOTHERISSUEISAHOWTOEVALUATEASTRONAUTPERFORMANCE/PTIMALLY THISEVALUA TION SHOULD BE PERFORMED DURING TRAINING AND ACTUAL SPACE MISSIONS 0ERFORMANCE WOULDTHENRESULTINARE EVALUATIONOFCREWCOMPOSITION4HISASSESSMENTISLIKELYTO INCREASE TENSION BETWEEN CREWMEMBERS MANAGEMENT AND MISSION CONTROLLERS &OR EXAMPLE CONTROLLERSIN-ISSION#ONTROLIN2USSIAWERESYSTEMATICALLYKEEPINGTRACK OFTHENUMBEROFERRORSPERFORMEDBYTHECREWONBOARD-IRORBYTHEGROUNDPERSON NEL&IGURE !LTHOUGHUSEFULFORDETERMININGACHANGEINPERFORMANCETHROUGH OUTAMISSION SOMEASTRONAUTSMIGHTSEESUCHEVALUATIONS ASWELLASTHEPSYCHOLOGISTS WHOPERFORMTHEM ASPOSSIBLETHREATSBECAUSETHEYFEARBEINGGROUNDEDORREMOVED FROMAMISSION )NRECENTYEARS HOWEVER VARIOUSTECHNIQUESOFPERFORMANCEANALYSISHAVEBEEN DEVELOPED4ESTBATTERIESCONSISTINGOFONEORANUMBEROFDISCRETEINDIVIDUALTASKSTO MEASURESUCHFACTORSASVIGILANCE REACTIONTIME TRACKING LIMBSTEADINESS COORDINATION

Figure 6.21. Number of Errors Made by the Crew and Ground Personnel During the Course of a 28-Day Mir Mission. (Oleg Atkov, Personal Communication).

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ANDPERCEPTUALSPEEDHAVEBEENUSEDDURINGSPACEMISSIONS#OMPARISONBETWEENTHE TIMESREQUIREDTOPERFORMTHESAMETASKINWEIGHTLESSNESSCOMPAREDTOGROUND FOR EXAMPLE PROVEDUSEFULTODETERMINEȃWORK EFʄCIENCYRATIOSȄ IE THETOTALESTIMATED TIMEDIVIDEDBYTHETOTALNUMBEROFHOURSAVAILABLETOWORK;+UBISETAL = 4HE EVALUATION BY PEERS PROVED TO BE AN EFFECTIVE TOOL TO ASSESS BOTH TECHNICAL SKILLSJOBPERFORMANCE ASWELLASTHEABILITYOFANINDIVIDUALTOLIVEANDWORKWITH OTHERSGROUPLIVING )NTHISTYPEOFEVALUATION ONECREWMEMBERISASKED FOREXAM PLE THE FOLLOWING QUESTIONS ȃ.AME THE ʄVE BEST CREWMEMBERS Ȅ ȃ.AME THE ʄVE WORSTCREWMEMBERS ȄANDȃ)FYOUCANȀTGOONAMISSION WHOSHOULDREPLACEYOUȄ 5SINGTHISTECHNIQUEINANALOGS ITWASFOUNDTHATVETERANSOFISOLATEDANDCONʄNED SITUATIONSGENERALLYPICKEDANEFFECTIVECREWIFGIVENALARGEAPPLICANTPOOLANDTIME TOCONDUCTTHOROUGHINTERVIEWS;.ATANI =0RELIMINARYRESULTSOFPEEREVALUATION PERFORMEDBYASTRONAUTSONEACHOTHERDURINGTRAININGONNINEDIMENSIONSOFPERFOR MANCEEG JOBCOMPETENCE LEADERSHIP TEAMWORK GROUPLIVING PERSONALITY COM MUNICATION SKILLS SHOWED REMARKABLE AGREEMENT WITH THE RATINGS DONE BY THE ASTRONAUTSSUPERVISORSANDDECISION MAKERS;2OSEETAL = (OWEVER MORE OBJECTIVE AND RELIABLE METHODS FOR OBSERVING AND RECORDING THE EFFECTOFSPACESTRESSESUPONCOMPLEXPERFORMANCEPROCESSESMUSTBEDEVELOPED4O DATE NOACTUALDATAHAVEBEENPUBLISHEDONASTRONAUTPERFORMANCE!S0ATRICIA3ANTY ; P=WROTEȃ3UCHDATAAREESSENTIALIFBEHAVIORALSCIENTISTSARETOUNDERSTAND INDIVIDUALANDGROUPPSYCHOLOGICALFACTORSASTHEYRELATETOINDIVIDUALANDCREWPER FORMANCEINSPACE7ITHOUTOBJECTIVEDATATOCLARIFYTHESERELATIONSHIPS EVENTHEBEST GUESSESABOUTWHATPSYCHOLOGICALCRITERIAARECRITICALINSELECTINGASTRONAUTSREMAIN ONLYGUESSESȄ

 0SYCHOLOGICALTRAININGANDSUPPORT ,ETȀS ASSUME THE SELECTION PROCESS PICKED OUT THE BEST INDIVIDUALS AND THAT THE MISSIONDIRECTOR WITHTHEHELPOFTHEPSYCHOLOGISTS THENPICKEDOUTTHEBESTCREWFOR A GIVEN LONG DURATION MISSION 4HE HAZARDS OF SUCH A MISSION AND THE UNKNOWN IMPLICATIONS OF STRESS ON HUMAN BEHAVIOR UNDER STRESS WILL UNDOUBTEDLY RESULT IN GROUP INTERACTIONISSUES0SYCHOLOGICALTRAININGISREQUIREDFORPREPARINGTHECREWTO REACTTOTHESESITUATIONS7HENCONʅICTSARISE PSYCHOLOGICALSUPPORTFROMTHEGROUND ALSOENTERSINTOPLAY 

4RAINING

/NE RULE OF THUMB IS THAT GROUP DYNAMICS AND GROUP PROBLEM SOLVING TECHNIQUES SHOULD BE DEALT WITH PRIOR TO THE MISSION !STRONAUTS NOT ONLY MUST BE TECHNICALLY PROʄCIENTINTHEIRAREATHEYMUSTALSOBEAWAREOFINTERPERSONALDYNAMICSANDINTER CULTURAL DIFFERENCES "OTH THE CREW AND THEIR GROUND CONTROL PERSONNEL SHOULD BE TRAINEDTOGETHERPREʅIGHTTOUSEINTERACTIVETECHNIQUES  -IKE#OLLINS;=WROTEȃ!S)USEDTOTELL*OHN9OUNGBEFORE'EMINI  )WASHAPPY)WASMAKINGMY ʄRSTSPACEʅIGHTWITHHIM BUT)WANTEDTOʅYSOBADLY)WOULDHAVEGONEUPWITHAKANGAROO
Ȅ

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



/PTIMALLY ONCEACREWHASBEENSELECTEDFORACERTAINMISSION ATRAININGORIENTED TO THAT SPECIʄC CREW SHOULD FOCUS ON THE FOLLOWING ISSUES A SUPPORT OF A TEAM BUILDING PROCESS WITHIN THE CREW THAT ESTABLISHES A STABLE CREW STRUCTURE DEVELOPS COMMONBEHAVIORALNORMS ANDIDENTIʄESOFCOMMONMISSIONGOALSANDB ȃANTICI PATORYPROBLEM SOLVINGȄTHATMAKESTHECREWMEMBERSAWAREOFHOWTODEALWITHTHE SPECIʄCPSYCHOLOGICALPROBLEMSTHATAREMOSTLIKELYTOARISEDURINGTHECOURSEOFA MISSION 4HREEPHASESOFTRAININGCANTHENBEIDENTIʄEDA APHASEOFAWARENESSWHENTHE CREWLEARNTHEBASICSOFGROUPDYNAMICSANDINTERPERSONALRELATIONSANDTHEIREFFECTS ONPERFORMANCEB THEGROUPRECEIVESFEEDBACKONTHEIRNEWLY LEARNEDCONCEPTSBY PUTTINGTHEMINTOPRACTICEINROLE PLAYINGANDSIMULATIONEXERCISESANDC THESECON CEPTSAREREINFORCEDREGULARLYTOPREVENTBACKSLIDING;.ICHOLASAND&OUSHEE = 5SINGTHISTYPEOFTRAINING ISSUESTHATONCECAUSEDTENSIONBETWEENCREWMEMBERS AND OUTSIDE MONITORING PERSONNEL HAVE BEEN AMELIORATED THROUGH ȃBULL SESSIONSȄ BOTH IN SIMULATIONS AND DURING ACTUAL SPACE MISSIONS ;3ANDAL = %XPERTS IN GROUP DYNAMICS WHO WORK WITH AND ARE TRUSTED BY THE CREWS ARE AVAILABLE ON THE GROUND TO ASSIST IN CONDUCTING SUCH SESSIONS DURING THE MISSION IF THE NEED ARISES ;0ALINKASETAL B= 7ORKTASKSANDSCHEDULESMIGHTBEPLANNEDTOMINIMIZESOCIALANDPSYCHOLOGICAL ISSUES ANDTOENSUREANDMAXIMIZEINDIVIDUALANDCREWPERFORMANCE&UTURECREWS SHOULD ALSO BE CONSULTED ON HABITAT FUNCTION AND DESIGN INCLUDING CLOTHING FOOD LAYOUT DECOR WASTE MANAGEMENT PERSONAL HYGIENE PRIVACY TOOL AND EQUIPMENT DESIGN ANDCOMPUTERHARDWAREANDSOFTWARE 0SYCHOLOGICALTRAININGISOFPRIMEIMPORTANCEFOR2USSIANCREWS#OSMONAUTSARE INVOLVEDFROMTHEMOMENTOFTHEIRSELECTIONINASERIESOFPSYCHOLOGICALTRAININGPRO CESSESDESIGNEDTOPREVENTTHEOCCURRENCEOFSEVEREADJUSTMENTPROBLEMSFORASPACE MISSION#OSMONAUTSARETESTEDINSIMULATORSANDINREAL WORLDSTRESSSITUATIONSSUCH ASPARACHUTEJUMPINGANDREMOTESURVIVALMISSIONS&IGURE 4HESEMISSIONSARE PLANNEDSOTHATTHEYAREASREALANDDANGEROUSASPOSSIBLE2OSCOSMOSSAYSTHATTHIS TYPEOFTRAININGDEVELOPSSELF CONʄDENCE DISCIPLINE ANDSTEADINESSDURINGANUNEX PECTED OR EMERGENCY SITUATION 4RAINING IN STRESSFUL SITUATIONS IS ALSO INTENDED TO MAKESURETHECREWWORKSTOGETHERASAHARMONIOUS WELL COORDINATEDUNIT 

3UPPORT

 3OVIETAND2USSIANEXPERIENCE 4HE3OVIET2USSIANEXPERIENCEINSPACEISEXTRAORDINARYFROMAPSYCHOLOGICALPOINT OF VIEW 4HE LEVEL OF SUPPORT THAT COSMONAUTS RECEIVE FROM START TO POST ʄNISH IS UNDOUBTEDLYAFACTORINTHESUCCESSOFTHEIRLONG DURATIONMISSIONPROGRAM/NTHE OTHER HAND THE 53 PSYCHOLOGICAL SUPPORT HAS BEEN MINIMAL UNTIL THE PROBLEMS ENCOUNTEREDBYTHE53ASTRONAUTSDURINGTHE.!3! -IRPROGRAMSEE4ABLE  %VERYCOSMONAUTMAKESDAYANDNIGHTJUMPSFROMDIFFERENTALTITUDES WHILEPERFORMINGTASKSTHATBECOME SUCCESSIVELYMOREDIFʄCULT&OREXAMPLE THEYMAYBEREQUIREDTOCARRYONARADIOCONVERSATION IDENTIFYING LOCATIONSONTHEGROUND BEFOREOPENINGTHEIRPARACHUTE4HISINTERESTFORPARACHUTINGCANBETRACEDBACKTO 9URI'AGARINȀSDAYWHERETHECOSMONAUTSBAILEDOUTOFTHE6OSTOKBEFORELANDING;CITEDBY#OLLINS =





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Figure 6.22. Astronauts Conduct an Emergency Egress Drill During Land Survival Training in the Wilderness. As Part of Generalized Stress Training, Crews Are Deposited in Extremely Hostile Environments and Survive only by Their Own Wits and Endurance. There Are No Rescue Teams to Help Out if Trainees Go into Trouble. (Credit NASA).

4HEPSYCHO SOCIALSUPPORTPROGRAMOFTHE2USSIAN3PACE!GENCYMAYNOTBEUSED EXACTLYASISBYTHEOTHERPARTNERSOFTHE)33BECAUSEOFTHECULTUREGAP BUTITISDEʄ NITELYASTARTINGPOINT &ROMTHEBEGINNINGOFTRAININGTOPOSTʅIGHT COSMONAUTSARECONSTANTLYMONITORED FORSTRESSANDPSYCHOLOGICALSYMPTOMOLOGY4HEYAREGIVENABATTERYOFPSYCHOLOGICAL TESTS PSYCHIATRIC INTERVIEWS AND ARE THOROUGHLY TESTED FOR COMPATIBILITY 4HE 0SYCHOLOGICAL 3UPPORT 'ROUP A SPECIALIZED CADRE OF PSYCHOLOGISTS MILITARY AND CIVILIANSPACEPERSONNELCONDUCTTHETESTINGANDMONITORING$RUGSTOREGULATEBEHAV IOR BIOFEEDBACK SELF HYPNOSIS ANDRELAXATIONSTRATEGIESAREALLUSEDINSUPPORTOFTHIS EFFORT;+ANAS = $URINGTHEʅIGHT THEREISANONGOINGMONITORINGOFVOICECOMMUNICATIONSBYPSY CHOLOGISTS IN -ISSION #ONTROL TO ASSESS CREW TENSION COHESION AND MORALE AND TO LOOKFORPOTENTIALINTERPERSONALPROBLEMS!NANALYSISOFVOICEPATTERNSOFTHECOSMO NAUTS IS ʄRST PERFORMED ON %ARTH DURING BOTH STRESSFUL AND NON STRESSFUL ACTIVITIES 4HESEARECOMPAREDTOVOCALPATTERNSTAKENONTHESPACESTATIONTOCHECKFORSTRESS 4WO WAYVIDEOOBSERVATIONSALSOAREUSEDTOINTERPRETFACIALEXPRESSIONSANDBODY LANGUAGEFORSIGNSOFSTRESS

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



)NADDITION COSMONAUTSAREROUTINELYSENTPERSONALITEMSANDDIFFERENTRECREATIONAL MATERIALSVIA0ROGRESSRE SUPPLYCAPSULES4HEYALSORECEIVECONSTANTREMINDERSOF %ARTH VIA NEWS BOOKS AUDIO AND VIDEO MATERIAL  AND HAVE FREQUENT CONTACT WITH FAMILYANDFRIENDSOVERPRIVATECOMMUNICATIONLINKS&IGURE  4HEPSYCHOLOGICALSUPPORTDOESNOTENDWITHTHEʅIGHT EITHER2ETURNINGCOSMO NAUTSAREHELPEDTOADJUSTTONEWFAMEANDTOREINTEGRATEWITHTHEIRFAMILIESAFTERSUCH ALONGABSENCE4HISISACHIEVEDTHROUGHCOUNSELING DRUGS ANDDEBRIEʄNGSASREQUIRED ;+ANAS =  )33PSYCHOLOGICALSUPPORT 4HE.!3!0SYCHOLOGICAL3ERVICES'ROUPWASESTABLISHEDINTOSUPPORTTHESTAY OFTHE53ASTRONAUTSONBOARD-IRDURINGTHE.!3! -IRPROGRAM0RIORTOESTABLISH ING THIS .!3! HAD FOCUSED FAR TOO LITTLE ATTENTION ON PSYCHOLOGICAL PROBLEMS AND THEIRRAMIʄCATIONS4HISISPARTLYDUETOTHEFACTTHATTHEREHADBEENLITTLENEEDBECAUSE OFTHESHORT DURATIONOFTHESPACEMISSIONSANDPARTLYBECAUSEOFAȃTECHNOLOGYAND HARDWAREʄRSTȄATTITUDE;3ANTY =4HISHASBEENCHANGINGRECENTLY AND.!3!IS BEGINNINGTOREALIZETHEIMPLICATIONSOFANASTRONAUTSUCCUMBINGTOTHESTRESSESOFHER HISENVIRONMENT4HE.!3!0SYCHOLOGICAL3ERVICES'ROUPISCOMPOSEDOFBEHAVIORAL SCIENTISTSANDPSYCHOLOGISTS WHOLEARNEDSIGNIʄCANTLYFROMTHEANALOGENVIRONMENTS

Figure 6.23. NASA Astronaut Norm Thagard in His Sleeping Compartment on Board Mir. (Credit NASA). !FTERMONTHSSPENTONBOARDTHE)33 THE%XPEDITION CREWMEMBERSMADEANINTERESTINGDESCRIPTIONOF THEIRʄRSTSENSATIONSAFTERTHEIR3OYUZLANDINGȃ7HENTHEHATCHʄRSTCRACKEDOPEN THESMELLSOFSPRINGON THE STEPPES AND THE SOUNDS OF BIRDS OVERWHELMED US 2EAL EARTHY SMELLS BECAUSE WEȀD STIRRED UP A FAIR AMOUNTOFDIRTWHENWELANDEDANDTHENWEROLLEDANDWEREDRAGGEDABIT3OYOUHADTHISFRESHDIRTSMELL WHICHWASJUSTABEAUTIFULSMELLȉANDITHADALITTLEBITOFCRUSHEDGRASSINIT TOO4HENTHENEXTTHINGTHAT HITUSWEREALLTHEBIRDSCHIRPINGȉ)TWASJUSTMUSICTOOUREARSȄ





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FROMTHEMANYYEARSOFEXPERIENCEOFTHE2USSIANPSYCHOLOGISTS ANDFROMSHARING LESSONSANDEXPERIENCEWITHOTHER)NTERNATIONAL0ARTNERS#3! %3! *!8!  4HEARRESTOFA.!3!ASTRONAUTIN&EBRUARYFORPERSONALACTIONSTHATWERETHE SUBJECTOFCRIMINALCHARGESLEDTOIMPROVEMENTSINTHEBEHAVIORALHEALTHCAREPROVIDED TO ASTRONAUTS AND THEIR DEPENDENTS 3INCE THIS INCIDENT A  MIN BEHAVIORAL HEALTH ASSESSMENT IS NOW CONDUCTED IN CONJUNCTION WITH EACH ASTRONAUTȀS ANNUAL MEDICAL ʅIGHTPHYSICALS"EHAVIORALMEDICINEʅIGHTASSESSMENTSAREALSONOWPERFORMEDON CREWMEMBERSBEFORETHEYLEAVEONANDRIGHTAFTERTHEYRETURNFROMASPACEMISSION 0REʅIGHTPSYCHOLOGICALSUPPORTBEGINSWHENCREWMEMBERSDEPLOYFORTRAININGIN 3TAR#ITY/NCETHERE TASKSINCLUDEADVOCATINGFORIMPROVEDCONDITIONSANDRESOURCES ASSISTINGWITHFAMILYCONTACTS ANDORGANIZINGOFF HOURSRECREATION4HISHELPISALSO DIRECTEDTOWARDALLSUPPORTPERSONNELTHATFOLLOWTHECREWMEMBERSWITHDEPLOYMENT 4HEGROUPISALSOINVOLVEDINȃVEHICLEȄISSUESTHATCOULDLATERAFFECTIN ʅIGHTPSY CHOLOGICAL SUPPORT SUCH AS HABITABILITY AND STOWAGE ACOUSTICS AND VIBRATION FOOD VARIETYANDSTORAGE ANDCREWQUARTERS3IMILARLY ITISINVOLVEDINȃHUMANȄISSUES SUCH AS THE WORK AND REST SCHEDULES LANGUAGE TRAINING AND CULTURE TRAINING #REWMEMBERSAREALSOFAMILIARIZEDWITHPOTENTIALIN ʅIGHTPSYCHO SOCIOLOGICALISSUES )MMEDIATEFAMILYISINVOLVEDINTHESETRAININGS ANDINFORMALMEETINGSSERVEINTHE PREPARATIONOFOFF HOURSONBOARDACTIVITIESBYSELECTINGMOVIES BOOKS ANDHOBBIESOF INTERESTFOREACHCREWMEMBER&IGURE  ! &AMILY 3UPPORT /FʄCE HAS ALSO BEEN CREATED WHICH INCLUDES REPRESENTATIVES FROM THE 0SYCHOLOGICAL 3ERVICES 'ROUP THE !STRONAUT /FʄCE AND THE !STRONAUT 3POUSES 'ROUP 4HIS STRUCTURE HAS A CRITICAL ROLE FOR SUPPORTING FAMILIES DURING ALL PHASESOFAMISSION ANDSERVESASALIAISONROLEWITHTHESPACEAGENCY4HROUGHTHIS ORGANIZATION THESPACEAGENCYMAINTAINSREGULARCONTACTWITHFAMILYPROVIDINGFOR EXAMPLE THE ASSISTANCE OF A FAMILY MEMBER OF ANOTHER ASTRONAUT OR ȃESCORTȄ AND PROVIDESINFORMATIONABOUTTHEMISSION ESPECIALLYCONTINGENCIES

Figure 6.24. U.S. Astronaut Steven Robinson Is Relaxing While Playing Guitar and Enjoying the View from the Cupola of the ISS. (Credit NASA).

0SYCHOLOGICAL)SSUESOF3PACEʅIGHT



)N ʅIGHT MONITORING OF ONBOARD ACTIVITIES BY THE 0SYCHOLOGICAL 3ERVICE 'ROUP ENSURESTHATTHEREISABALANCEDREGIMEOFMEANINGFULWORKANDREST-ONITORINGOFTHE ASTRONAUTS INCLUDES A QUESTIONNAIRE ON MOOD SLEEP AND STRESS AND COUNTERMEASURE USAGEANDEFFECTIVENESS4HEREAREDAILYPRIVATECOMMUNICATIONSBETWEENCREWMEM BERSANDʅIGHTSURGEONSAND LESSFREQUENTLY WITHPSYCHOLOGICALSUPPORTPERSONNEL 3OMECOGNITIVEASSESSMENTMETHODS ANDWELLASBEHAVIORALANDFATIGUEASSESSMENT TOOLSAREBEINGDEVELOPEDTOLOOKFORPOTENTIALINTERPERSONALPROBLEMS )N ʅIGHTSUPPORTACTIVITIESINCLUDESURPRISEPRESENTSANDFAVORITEFOODSSENTUPVIA 0ROGRESS AND THE SHUTTLE TWO WAY COMMUNICATION WITH FAMILY AND FRIENDS ON THE GROUND VIA PRIVATE AUDIO VIDEO LINKS SPECIAL FAMILY CONFERENCES ON HOLIDAYS EG BIRTHDAYS -OTHERȀS$AY COMMUNICATIONSWITHFRIENDS SCIENTISTS ACTORS ANDARTISTS AUDIOANDVIDEONEWSANDSPORTSNEWS E MAIL INSTANTMESSAGING SOCIALNETWORKING AMATEUR RADIO COMMUNICATION AND ONBOARD RECREATIONAL SOFTWARE AND AUDIO VIDEO MATERIAL FOR LEISURE TIME USE ! COMPUTER BASED FAMILY PICTURE ALBUM OF SPOUSES FRIENDS ANDCO WORKERSISALSOPROPOSED !FTERTHEʅIGHT DEBRIEʄNGSAREIMPLEMENTEDWITHBOTHTHECREWMEMBERSANDTHEIR FAMILYTOHELPTHEMREADJUSTTOTHEIRLIFEON%ARTH4HESEMEETINGSAREALSOUSEDTO ASSESSTHEOVERALLPSYCHOLOGICALHEALTHOFTHEINDIVIDUALSANDASACOUNTERMEASUREFOR ADDRESSING RESIDUAL INTRA CREW CREW FAMILY AND GROUND CREW TENSIONS THAT MAY DEVELOPDURINGLONG DURATIONMISSIONS4HEOTHEROBJECTIVEOFTHESEMEETINGSISTO ASSESSTHEPRACTICALVALUEOFTHECURRENTPSYCHOLOGICALPREPARATIONANDSUPPORT ANDTO OBTAINRECOMMENDATIONSFORIMPROVINGTHEPSYCHOLOGICALSUPPORTFORFOLLOWINGCREWS ;!RKAND#URTIS =&IGURE   5NSOLVEDISSUES $ESPITETHEIREXPERIENCEOFLONG DURATIONMISSIONS ANDTHEATTENTIONGIVENTOSELEC TION OF COSMONAUTS PSYCHOLOGICAL TRAINING AND SUPPORT NUMEROUS REVIEWERS HAVE POINTED OUT THAT COSMONAUTS HAVE FACED PERIODS OF DEPRESSION ;+ANAS = &OR EXAMPLE #OSMONAUT6ALENTIN,EBEDEV;= AFTERSPENTINORBIT WROTETHEFOL LOWING DEPRESSED THOUGHTS IN HIS DIARY ȃ(UMMING TO MYSELF ) ʅOAT THROUGH THE ;3ALYUT=STATION;ȉ=)SITPOSSIBLETHATSOMEDAY)ȀLLBEBACKON%ARTHAMONGMYLOVED ONES AND EVERYTHING WILL BE ALL RIGHTȄ 4HIS EXAMPLE SHOWS THAT THERE ARE SERIOUS PSYCHOLOGICALANDSOCIALDISTURBANCESDURINGLONG DURATIONSPACEʅIGHT.OPSYCHO LOGICALSELECTIONSTRATEGYBYITSELFWILLEXCLUDETHATPOSSIBILITY

 !MAZINGLY EVENTHOUGHCREWMEMBERSOFTHE)33LIVEANDWORKSOCLOSETOGETHER ALOTOFTHEIRREAL COMMUNICATION TAKES THE FORM OF WRITTEN WORDS )N THE INFORMATION AGE AND WITH COMPUTERS AT EACH WORKSTATION ASTRONAUTSANDCOSMONAUTSARECOMMUNICATINGBETWEENTHEMSELVESANDOTHERSMOREVIA E MAILANDINSTANTMESSAGINGTHATVERBALLY;2OBERT4HIRSK PERSONALCOMMUNICATION =4HISISGOOD TRAININGBECAUSEDURINGTHEMISSIONTO-ARS COMMUNICATIONWITHTHEGROUNDUSINGE MAILWILLBETHE LEASTAFFECTEDBYTHE MINDELAY  3USAN(ELMS ACREWMEMBEROFTHE)33%XPEDITION  SAIDȃ"EFORE)WENTUPONTHE)33FORMONTHS )MOVEDOUTOFMYPLACE PUTALLMYPOSSESSIONSINSTORAGE ANDMOVEDINTOTHEASTRONAUTSCREWQUARTERS EARLIERTHANMOSTPEOPLEDO)DIDNȀTWANTTELEPHONEORCREDITCARDBILLS ORANYTHINGEXCEPTABANKACCOUNT WHEREMYPAYCHECKCOULDGO)ʄGUREDIF)DIDNȀTHAVEAHOMEBACKHERETOWORRYABOUT THE)33COULD BECOMEMYHOMEȉ )WANTEDITTOBELIKEAMILITARYDEPLOYMENT LIKE.AVYGUYSWHOGOOUTONASHIP FORMONTHSANDPUTALLTHEIRSTUFFINSTORAGEȄ



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Figure 6.25. At the NASA Kennedy Space Center, the STS-133 Crew Takes a Break from the Rigors of a Simulated Launch Countdown to Have a Little Fun Hamming it up. (Credit NASA).

!NOTHERSOURCEOFCONCERNISTHATWEDONȀTKNOWWHATISGOINGTOHAPPENWHEN ASTRONAUTS EMBARK ON A  YEAR TRIP TO -ARS OR ANOTHER PLANET 4HE ISOLATION DURING SUCHAMISSIONISUNIQUE BECAUSEEVENTHE%ARTHWILLNOTBEVISIBLETOTHECREWSEE &IGURE ANDTHEREWILLBELONGDELAYSINCOMMUNICATION#REWMEMBERSWILLNEED TO DEAL WITH PSYCHIATRIC PROBLEMS THEMSELVES WITH NO POSSIBILITY OF EVACUATING AN AFFECTED INDIVIDUAL /NE THING THAT WE KNOW OR SHOULD KNOW IS THAT THE FUTURE OF SPACEEXPLORATIONWILLREQUIREINCREASEDINPUTFROMTHEPSYCHOLOGICALANDSOCIALSCI ENCECOMMUNITY #AREFULATTENTIONTOSELECTION TRAINING ANDORGANIZATIONALFUNCTIONSSHOULDPERMIT SMALLGROUPSOFINDIVIDUALSTOLIVEANDWORKEFFECTIVELYINSPACEFORCONTINUOUSPERI ODSOFSEVERALMONTHSORYEARS"UTTHEREAREENORMOUSGAPSINOURUNDERSTANDINGOF HOWTHEMULTIPLE COMPLEXBEHAVIORALFACTORSOPERATEINDEPENDENTLYTOINʅUENCETHE BEHAVIOROFINDIVIDUALSANDGROUPS)TISTHEREFORENECESSARYTOCONTINUETHERESEARCH INTHISAREA ASRECOMMENDEDINTHEREPORTBYTHE.ATIONAL2ESEARCH#OUNCILENTITLED !3TRATEGYFOR2ESEARCHIN3PACE"IOLOGYAND-EDICINEINTHE.EW#ENTURY;= ANDMORERECENTLY INTHE.!3!(UMAN2ESEARCH2OADMAPFOREXPLORATIONMISSIONS SEE#HAPTER 4ABLE  )TWILLBEALSONECESSARYTODEVELOPMOREEFFECTIVECOUNTERMEASURESTOADDRESSTHE INDIVIDUAL GROUP ANDCULTURALISSUESINVOLVEDINTHESESPACEMISSIONS)NPARTICULAR THEFOLLOWINGCOUNTERMEASURESNEEDTOBEADDRESSEDFURTHER A -AINTAINING THE PRESENCE OF BEHAVIOR AND PERFORMANCE SPECIALISTS THROUGH ALL PHASESOFSPACEMISSIONDESIGN B 3ELECTINGFULLMISSIONCREWSANDCRITICALGROUNDPERSONNELASATEAM C 4RAININGTHEASTRONAUTSINPSYCHOLOGICALMETHOD

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D %MBEDDINGTESTSOFCOGNITIVE EMOTIONALANDBEHAVIORALPERFORMANCEINFUNCTION INGMISSIONHARDWAREANDEXPERIMENTS E 'REATERUSEOFSIMULATORSFORTRAININGONBOARDTHEMISSION F &URTHERDEVELOPMENTOFSELF REPORTTOOLSLIKEDIARIES PERSONALLOGS ANDCOMPUTER ʄLES G $EVELOPINGVIRTUALENVIRONMENTSANDTELESCIENCETOADDRESSBEHAVIORANDPERFOR MANCEASPECTSOFMISSIONS H 5SINGGROUND BASEDANALOGSANDSIMULATORSFORSELECTIONANDTRAINING I &URTHERTRAININGOFMISSIONANDGROUNDCREWSTOGETHER "EHAVIORALANDSOCIALPROBLEMSHAVEBEENREGARDEDTODATEASOBSTACLESORȃSHOW STOPPERSȄTOLONG DURATIONSPACEMISSIONS!DEQUATEPSYCHOLOGICALSELECTION TRAIN ING ANDSUPPORTCANMINIMIZETHESEPROBLEMS3OMERESEARCHISNEEDED HOWEVER BECAUSEMANYFACTORSINVOLVEDINPERSONALANDGROUPDYNAMICSINAHOSTILEENVIRON MENT ARE STILL UNKNOWN %VEN MORE IMPORTANT FROM A LIFE SCIENCES PERSPECTIVE IT SEEMSLIKELYTHATENTIRELYNEWPRINCIPLESOFHUMANINTERACTIONANDGROUPDYNAMICS WILLEMERGEASARESULTOFSUCHRESEARCHTOENSUREEFFECTIVEHUMANBEHAVIORINSPACE ENVIRONMENTSANDITSANALOGS

2EFERENCES !RK36 #URTIS+ 3PACEʅIGHTANDPSYCHOLOGY0SYCHOLOGICAL3UPPORTFOR3PACE 3TATION -ISSIONS "EHAVIORAL (EALTH AND 0ERFORMANCE 'ROUP (OUSTON 48 .!3!*OHNSON3PACE#ENTER "ECHTEL2" "ERNING! !4HETHIRD QUARTERPHENOMENON$OPEOPLEEXPERI ENCEDISCOMFORTAFTERSTRESSHASPASSED)N&ROM!NTARCTICATO/UTER3PACE,IFE IN )SOLATION AND #ONʄNEMENT (ARRISON !! #LEARWATER 9! -C+AY #0 EDS .EW9ORK3PRINGER6ERLAG PPǻ "ISHOP3 0SYCHO 3OCIOLOGICAL)SSUESOF3PACEʅIGHT!DVANCED,ECTUREATTHE )NTERNATIONAL3PACE5NIVERSITY 3UMMER3ESSIONIN(OUSTON 4EXAS "LUTH"* (ELPIE- 3OVIET3PACE3TATIONAS!NALOGS;WITH-IRUPDATE=.!3! 'RANT.!'7 7ASHINGTON $#.!3!(EADQUARTERS "ONDAR 2,  3PACE QUALIʄED HUMANS 4HE HIGH ʄVE !VIATION 3PACE  %NVIRONMENTAL-EDICINEǻ "UI , 7ONG *  )NTERCULTURAL 3TUDY OF 0ERSONAL 3PACE 0RESENTATION AT THE )NTERNATIONAL3PACE5NIVERSITY3UMMER3ESSION 0OMONA #! "URROUGH" $RAGONʅY.EW9ORK .9(ARPER#OLLINS #AMPBELL!% -ULTI #ULTURAL$YNAMICSIN3PACE3TATIONS0APERPRESENTEDAT THETH)NTERNATIONAL!STRONAUTICAL#ONGRESS 3TOCKHOLM 3WEDEN #HAIKIN! 4HELONELINESSOFTHELONG DISTANCEASTRONAUT$ISCOVER &EBRUARY ISSUE #OLLINS- -ISSIONTO-ARS.EW9ORK .9'ROVE7EIDENFELD #ONNORS -- (ARRISON !! !KINS &2  ,IVING !LOFT (UMAN 3PACEʅIGHT 2EQUIREMENTSFOR%XTENDED3PACEʅIGHT7ASHINGTON $#.!3!3CIENTIʄCAND )NFORMATION"RANCH &RASER 4-  ,EISURE AND RECREATION IN LONG DURATION SPACE MISSIONS (UMAN &ACTORSǻ



&UNDAMENTALSOF3PACE-EDICINE

(ALL%4 4HE(IDDEN$IMENSION-ANȀS5SEOF3PACEIN0UBLICAND0RIVATE ,ONDON"ODLEY(EAD (ARRISON!! #ONNORS-- 'ROUPSINEXOTICENVIRONMENTS)N!DVANCESIN %XPERIMENTAL3OCIAL0SYCHOLOGY"ERKOWITZ,:ED .EW9ORK .9!CADEMIC 0RESS 6OLUME PPǻ (ARRISON! #LEARWATER9 -C+AY# &ROM!NTARCTICTO/UTER3PACE,IFEIN )SOLATIONAND#ONʄNEMENT.EW9ORK .93PRINGER 6ERLAG (ELMREICH2, 7ILHELM*! 2UNGE4% 0SYCHOLOGICALCONSIDERATIONSINFUTURE SPACEMISSIONS)N(UMAN&ACTORSOF/UTER3PACE0RODUCTION#HESTON3 7INTER $EDS "OULDER7ESTVIEW0RESS PPǻ +ANAS .  0SYCHOSOCIAL SUPPORT FOR COSMONAUTS !VIATION 3PACE AND %NVIRONMENTAL-EDICINEǻ +ANAS . -ANZEY $  3PACE 0SYCHOLOGY AND 0SYCHIATRY %L 3EGUNDO #! -ICROCOSM0RESS AND$ORDRECHT 4HE.ETHERLANDS+LUWER!CADEMIC0UBLISHERS +ANAS .! 3ALNITSKIY60 "OYD*% ETAL #REWMEMBERANDMISSIONCONTROL PERSONNEL INTERACTIONS DURING )NTERNATIONAL 3PACE 3TATION MISSIONS !VIATION 3PACE%NVIRONMENTAL-EDICINEǻ +ELLY!$ +ANAS. #OMMUNICATIONBETWEENSPACECREWSANDGROUNDPERSON NEL!SURVEYOFASTRONAUTSANDCOSMONAUTS!VIATION 3PACE%NVIRONMENTAL -EDICINEǻ +UBIS*& -C,AUGHLIN%* *ACKSON*- 2USNAK2 -C"RIDE'( 3AXON36 4ASKANDMOTORPERFORMANCEON3KYLABMISSIONS  AND4IMEMOTIONSTUDY EXPERIMENT-)N"IOMEDICAL2ESULTSFROM3KYLAB*OHNSTON23 $IETLEIN,& EDS 7ASHINGTON $#.!3!30  PPǻ ,EBEDEV6 $IARYOFA#OSMONAUT$AYSIN3PACE#OLLEGE3TATION 48 0HYTORESOURCE2ESEARCH)NC )NFORMATION3ERVICE ,INENGER*- /FFTHE0LANET.EW9ORK .9-C'RAW (ILL .!3$! ,ESSONS,EARNEDFROM3&).#33 ANDITS!PPLICATIONTO"EHAVIORAL 3UPPORT0ROGRAM4OKYO.!3$!4-2  .ATANI +  &UTURE DIRECTIONS FOR SELECTING PERSONNEL )N (UMAN &ACTORS OF /UTER 3PACE PRODUCTION #HESTON 3 7INTER $ EDS "OULDER #/ 7ESTVIEW 0RESS PPǻ .ATIONAL 2ESEARCH #OUNCIL  ! 3TRATEGY FOR 2ESEARCH IN 3PACE "IOLOGY AND -EDICINEINTHE.EW#ENTURY3PACE3TUDIES"OARD .ATIONAL2ESEARCH#OUNCIL 7ASHINGTON $#.ATIONAL!CADEMY0RESS .ICHOLAS*- &OUSHEE(# /RGANIZATION SELECTION ANDTRAININGOFCREWSFOR EXTENDED SPACEʅIGHT &INDINGS FROM ANALOGS AND IMPLICATIONS *OURNAL OF 3PACECRAFT2OCKETSǻ /BERG*% 2ED3TARIN/RBIT.EW9ORK .92ANDOM(OUSE 0ALINKAS ,!  (EALTH AND PERFORMANCE OF !NTARCTIC WINTER OVER PERSONNEL !FOLLOW UPSTUDY!VIATION 3PACEAND%NVIRONMENTAL-EDICINEǻ 0ALINKAS,! 'ROUPADAPTATIONANDINDIVIDUALADJUSTMENTIN!NTARCTICAASUM MARYOFRECENTRESEARCH)N&ROM!NTARCTICATO/UTER3PACE,IFEIN)SOLATIONAND #ONʄNEMENT (ARRISON !! #LEARWATER 9! -C+AY #0 EDS .EW 9ORK .9 3PRINGER 6ERLAG PPǻ

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0ALINKAS,! 'UNDERSON%+% *OHNSON*# (OLLAND!7A "EHAVIORANDPER FORMANCEONLONG DURATIONSPACEʅIGHTS%VIDENCEFROMANALOGUEENVIRONMENTS !VIATION 3PACE%NVIRONMENTAL-EDICINE 3UPPL !ǻ 0ALINKAS,! 'UNDERSON%+% (OLLAND!7 -ILLER# *OHNSON*#B 0REDICTORS OF BEHAVIOR AND PERFORMANCE IN EXTREME ENVIRONMENTS 4HE !NTARCTIC 3PACE !NALOGUE0ROGRAM!VIATION 3PACE%NVIRONMENTAL-EDICINEǻ 2OBINS,. (ELZER*% 7EISSMANNETAL ,IFETIMEPREVALENCEOFSPECIʄCPSY CHIATRICDISORDERSINTHREESITES!RCHIVESIN'ENERAL0SYCHIATRYǻ 2OSE 2- (ELMREICH 2, &OGG , -C&ADDEN 4  !SSESSMENTS OF ASTRONAUT EFFECTIVENESS!VIATION 3PACEAND%NVIRONMENTAL-EDICINEǻ 3ANDAL'- 0SYCHOSOCIALISSUESINSPACE&UTURECHALLENGES'RAVITATIONALAND 3PACE"IOLOGY"ULLETINǻ 3ANDAL '- 6AERNES 2 5RSIN (  )NTERPERSONAL RELATIONS DURING SIMULATED SPACEMISSIONS!VIATION 3PACE%NVIRONMENTAL-EDICINEǻ 3ANDAL'- 6AERNES2 "ERGAN4 7ARNCKE- 5RSIN( 0SYCHOLOGICALREAC TIONS DURING POLAR EXPEDITIONS AND ISOLATION IN HYPERBARIC CHAMBERS !VIATION 3PACE%NVIRONMENTAL-EDICINEǻ 3ANTY0! #HOOSINGTHE2IGHT3TUFF4HE0SYCHOLOGICAL3ELECTIONOF!STRONAUTS AND#OSMONAUTS7ESPORT #ONNECTICUT0RAEGER 3ANTY 0!  "EHAVIOR AND PERFORMANCE IN THE SPACE ENVIRONMENT )N &UNDA MENTALSOF3PACE,IFE3CIENCES3#HURCHILLED -ALABAR &,+RIEGER0UBLISHING #OMPANY 6OLUME #HAPTER PPǻ 3ANTY0! (OLLAND!7 &AULK$- 0SYCHIATRICDIAGNOSESINAGROUPOFASTRO NAUTS!VIATION 3PACE%NVIRONMENTAL-EDICINEǻ 3HAYLER$ !ROUNDTHE7ORLDIN$AYS4HE!UTORIZED"IOGRAPHYOF3KYLAB !STRONAUT*ERRY#ARR"URLINGTON #ANADA!POGEE"OOKS 3MITH3 (AYTHORN77 %FFECTSOFCOMPATIBILITY CROWDING GROUPSIZE AND LEADERSHIPSENIORITYONSTRESS ANXIETY HOSTILITY ANDANNOYANCEINISOLATEDGROUPS *OURNALOF0ERSONALITYAND3OCIAL0SYCHOLOGYǻ 3TUSTER *#  "OLD %NDEAVORS ,ESSONS FROM 0OLAR AND 3PACE %XPLORATION !NNAPOLIS -$.AVAL)NSTITUTE0RESS 3TUSTER*# "ACHELARD# 3UEDFELD 0 )NTHE7AKEOFTHE!STROLAB2EVIEWAND !NALYSISOF$IARIES-AINTAINEDBYTHE,EADERSAND0HYSICIANSAT&RENCH2EMOTE $UTY 3TATIONS 4ECHNICAL 2EPORT  FOR THE .ATIONAL !ERONAUTICS AND 3PACE !DMINISTRATION3ANTA"ARBARA #!!NACAPA3CIENCES )NC 3TUSTER *# "ACHELARD # 3UEDFELD 0  4HE RELATIVE IMPORTANCE OF BEHAVIORAL ISSUES DURING LONG DURATION )#% MISSIONS !VIATION 3PACE AND %NVIRONMENTAL -EDICINE!ǻ! 4AYLOR$! 7HEELER, !LTMAN) 3TRESSREACTIONSINSOCIALLYISOLATEDGROUPS *OURNALOF0ERSONALITYAND3OCIAL0SYCHOLOGYǻ 7EYBREW"" .ODDIN%- 0SYCHIATRICASPECTSOFADAPTATIONTOLONGSUBMARINE MISSIONS!VIATION 3PACE%NVIRONMENTAL-EDICINEǻ :UBRIN 2  %NTERING 3PACE #REATING A 3PACEFARING #IVILIZATION .EW 9ORK 0ENGUIN0UTNAM)NC

#HAPTER /PERATIONAL3PACE-EDICINE

#REWHEALTHCARETHROUGHALLPHASESOFSPACEʅIGHTISAFURTHERASSURANCEMEASUREFOR MISSIONSUCCESS&LIGHTSURGEONSSHEPHERDTHEIRASSIGNEDCREWMEMBERSTHROUGHALL MISSION PHASES INCLUDING TRAINING MEDICAL EXAMS PRE LAUNCH SUIT UP AND POST LANDINGRECOVERY4HESEDOCTORSARESOESSENTIALTHATTHEYAREALWAYSʄRSTONSCENE FORLANDING)FCREWMEMBERSWERENOTMENTALLYANDPHYSICALLYHEALTHY THEIRNOMINAL ANDEMERGENCYINTERACTIONSWITHTHEVEHICLEMIGHTBEFATALLYCOMPROMISED $ESPITE CAREFUL SCREENING EXTENSIVE TRAINING AND AGGRESSIVE COUNTERMEASURES AGAINST THE PHYSIOLOGICAL CHALLENGES ENCOUNTERED DURING SPACEʅIGHT INCIDENTS OF AMBULATORYILLNESSANDMEDICALEMERGENCIESAREACERTAINTYFORBOTHSHORT ANDLONG DURATION SPACE MISSIONS )N THIS CHAPTER STRATEGIES THAT EVALUATE THE PROBABILITY OF MEDICALEVENTSASWELLASTHEMEDICALHARDWARE PROCEDURES ANDPHYSICIANANDSUR GEONRESOURCESNEEDEDTOMITIGATETHEMAREEXPLORED4HESERISKMITIGATIONSTRATEGIES ARE USED AS THE BASIS FOR DESIGN OF HEALTH CARE PROCEDURES AND FACILITIES IN SPACE &IGURE 

 3PACEMEDICINEWHATISIT !SHUMANSESTABLISHAPERMANENTPRESENCEINSPACE WHETHERITISONASPACESTATIONOR ON PLANETARY BODIES IT WILL BE IMPERATIVE THAT HEALTH CARE BE PROVIDED TO WORKERS SCIENTISTS ANDASTRONAUTS4HEREQUIREDMEDICALFACILITIES PROCEDURES ANDEXPERTISE NEEDEDTOTREATTHESECREWMEMBERSAREUNIQUETOTHECONSTRAINTSANDSTRESSESOFSPACE &IGURE ANDTOTHEPHYSIOLOGICALCHANGESDESCRIBEDINTHEPRECEDINGCHAPTERS /NEESSENTIALASPECTOFAHEALTHMAINTENANCEFACILITYISITSINTERRELATIONTOOTHERLIFE SCIENCESACTIVITIES%XPERIENCEINTHEDEVELOPMENTOFMODERNMEDICINEOVERTHEPAST CENTURYHASSHOWNASTRONGCORRELATIONBETWEENOPTIMALMEDICALCAREANDSCIENTIʄC INVESTIGATION4HISCONCEPTALSOAPPLIESTOSPACEMEDICINE$OINGSOPOSITIVELYAFFECTS NOTONLYTHEQUALITYOFCAREBUTALSOTHEQUALITYOFRESEARCHINSPACEPHYSIOLOGY !SINANYOTHERMEDICALʄELDON%ARTH SPACEMEDICINEINVOLVESBOTHPROACTIVEAND REACTIVECAREOFHUMANSTOOPTIMIZEPHYSICAL PHYSIOLOGICAL ANDMENTALWELLBEING WITHINTHEUNIQUECONSTRAINTSOFANEXTREMEENVIRONMENT5NLIKEONTHEGROUND THE ʄRSTPRIORITYISTOSUPPORTTHEMISSION%NSURINGTHEHEALTHANDSAFETYOFTHECREWMEM BERSIS INAWAY ASECONDARYOBJECTIVEBUTITISNECESSARYFORFULʄLLINGTHEʄRST4OPUT THISPRINCIPLEINCONTEXT ONEMUSTREMEMBERTHATIFTHEPRIMARYGOALWERETOKEEPA SELECTGROUPOFINDIVIDUALSASHEALTHYANDSAFEASPOSSIBLE THEYWOULDBEKEPTSAFELY ONTHEGROUND3PACEʅIGHTISINHERENTLYRISKY4HECLOSESTANALOGTOSPACEMEDICINE G. Clément, Fundamentals of Space Medicine, Space Technology Library 23, DOI 10.1007/978-1-4419-9905-4_7, © Springer Science+Business Media, LLC 2011





&UNDAMENTALSOF3PACE-EDICINE

Figure 7.1. The Roles of Nurse Christine Chapel (Majel Barrett) and Dr. Leonard “Bones” McCoy (DeForest Kelley) Were a Vital Part of the Success of the Original Star Trek Series. (Credit Paramount Pictures).

Figure 7.2. One Astronaut Performs a Dental Examination on a Crewmate During a Skylab Mission. (Credit NASA).

WOULDBEAVIATIONMEDICINEASPRACTICEDBYTHEMILITARYʅIGHTSURGEON!GAIN MISSION ASSURANCEISTHEʄRSTPRIORITYOFALLOPERATIONALSUPPORT;"ARRATT = 4HEREFORE SPACEMEDICINEISDIFFERENTFROMSPACEPHYSIOLOGYMANYOFTHEPHYSI OLOGICALCHANGESTOWEIGHTLESSNESSARESIMPLYADAPTIVE NOTNECESSARILYPATHOLOGIC #ERTAINLYTHEREARESOMEADAPTIVEPROCESSES SUCHASBONEDEMINERALIZATION ASWELLAS

/PERATIONAL3PACE-EDICINE



ENVIRONMENTAL EXPOSURES SUCH AS RADIATION THAT MAY BE CONSIDERED PATHOLOGIC BECAUSEWITHOUTCOUNTERMEASURESTHEYMAYEVENTUALLYCOMPROMISEHEALTHDURINGA MISSION !LSO MANY OF THE ADAPTIVE RESPONSES TO WEIGHTLESSNESS SUCH AS CARDIO VASCULAR MUSCULAR ANDNEURO SENSORYDECONDITIONING BECOMEMALADAPTIVEONRETURN TONORMALGRAVITY)THASOFTENBEENSAIDTHATIFONEDIDNOTHAVETORETURNTO%ARTH LOW %ARTH ORBIT WOULD BE A GREAT PLACE
&INALLY EVEN A NON MALADAPTIVE AND NON PATHOLOGICCHANGEMAYALTERTHEWAYINWHICHAGIVENILLNESSMIGHTPRESENTANDBE MANAGED CAUSINGSPACEMEDICINEPRACTITIONERSTOCREATIVELYREASSESSTHEIRDIAGNOSTIC ANDTHERAPEUTICPROCESSES;"ARRATT = 

/BJECTIVES

ȃ)L VAUT MIEUX PR¦VENIR QUE GU¦RIRȄ ȃAN OUNCE OF PREVENTION IS WORTH A POUND OF CUREȄ 4HEWISDOMOFTHISADAGEISPROFOUNDWITHREGARDTOPLANNINGACTIVITIESINTHE HOSTILE ISOLATEDENVIRONMENTOFSPACEʅIGHT;(OLLANDAND-ARSH=3ELECTIONOF THEBEST ʄTINDIVIDUALSISTHEʄRSTSTEPOFAHEALTHMAINTENANCEPROGRAM4HEMEDICAL REQUIREMENTSFORTHESELECTIONOFASTRONAUTSWILLBEDETAILEDINSUBSEQUENTSECTIONSOF THISCHAPTER /NCETHEPERSONNELHAVEBEENSELECTED THESECONDCOMPONENTISPREVENTION THAT IS THEMAINTENANCEOFPHYSICALANDMENTALHEALTH#ONSIDERATIONSINCLUDEPHYSIOLOGI CAL STATUS MONITORING NUTRITION AND STRESS MANAGEMENT SAFE WASTE MANAGEMENT HYGIENE MEDICAL RECORD KEEPING ENVIRONMENTAL MONITORING EXERCISE DEVICES AND MEDICALRESEARCHFACILITIES ASSURANCEOFASUITABLESLEEPENVIRONMENT RECREATIONAND ENTERTAINMENT SOCIALSUPPORTAIDS ANDCOMMUNICATIONWITHFAMILYANDFRIENDS 7HEN SELECTION AND PREVENTION ARE UNABLE TO MITIGATE THE DELETERIOUS EFFECTS OF SPACEʅIGHT COUNTERMEASURES ARE USED #OUNTERMEASURES FOR MOTION SICKNESS POST ʅIGHTORTHOSTATICINTOLERANCE BONEDEMINERALIZATIONANDMUSCLEATROPHY ANDPSYCHO LOGICALISSUESHAVEBEENDESCRIBEDINTHEPREVIOUSCHAPTERS7HENSELECTION PREVENTION ANDCOUNTERMEASURESAREUNABLETOPREVENTORMITIGATEILLNESSORINJURY THENTREATMENT ISUSED )NADDITIONTOTHEABOVE REHABILITATIONSHOULDBECONSIDEREDSOASTOENHANCEOPTI MALCREWPRODUCTIVITYANDRETURNTOOPERATIONALCAPABILITY#ONSEQUENTLY THETYPESOF CARETHATAHEALTHMAINTENANCEFACILITYMUSTPROVIDEONAMINIMALBASISFALLINTOTHESE ʄVE CATEGORIES SELECTION PREVENTION COUNTERMEASURES TREATMENT OF DISEASE AND INJURY ANDREHABILITATION 

2ISKASSESSMENT

2ISKS ARE THE CONDITIONAL PROBABILITY OF THE OCCURRENCE OF AN ADVERSE EVENT FROM EXPOSURETOTHESPACEENVIRONMENT3UCHEXPOSURECANRESULTINDYSFUNCTIONALPHYSI OLOGICALORBEHAVIORALADAPTATIONTHATCOULDLEADTOINCREASEDINJURIES ILLNESS LOSSOF LIFE ORLOSSOFMISSIONOBJECTIVES)NJURYISTHEMOSTLIKELYDEBILITATINGORPOTENTIALLY

#OUNTERMEASURESANDREHABILITATIONHAVEALREADYBEENCOVEREDINPREVIOUSCHAPTERS INPARTICULARREGARD INGTHEBONEANDMUSCLESYSTEMSSEE#HAPTER 3ECTION ANDTHEPSYCHOLOGICALISSUESSEE#HAPTER 3ECTION 





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LIFE THREATENING PROCESS IN YOUNG HEALTHY INDIVIDUALS 4HERE ARE HOWEVER CERTAIN MEDICALANDSURGICALEMERGENCIESTHATAFFECTEVENYOUNGPEOPLE SUCHASAPPENDICITIS PERFORATEDULCER RENALSTONES ANDSUBARACHNOIDHEMORRHAGE4HE0OLARISSUBMARINE EXPERIENCE FROM  TO  REVEALED  SURGICAL CASES IN    MAN DAYS 4HEREHAVEBEENAPPROXIMATELYCASESOFAPPENDICITIS OFWHICHWERESUCCESS FULLYTREATEDWITHANTIBIOTICS ANDFOUROFWHICHRESULTEDINDEATH;(AMILTON = 7HENREVIEWINGTHEMEDICALEXPERIENCEOFTHE53.AVY THE!NTARCTICWINTER OVERSTATISTICS ANDTHE3OVIET2USSIANSPACEEXPERIENCEONLONG DURATIONMISSIONS IT CANBEREASONABLYEXPECTEDTHATACRITICALMEDICALEVENTREQUIRINGSURGERYEG APPEN DECTOMY INAPERMANENTSPACESTATIONOFSIXASTRONAUTSWOULDOCCUREVERYYEARS ;(AMILTON ='IVENTHEFACTTHATTHEREHASBEENAQUASI PERMANENTHUMANPRES ENCEINSPACESINCE ʄRSTON-IRANDTHENONTHE)33&IGURE SURGERYIN SPACECOULDSOONBEANECESSITY3URGERYISTHEONLYALTERNATIVEWHENANTIBIOTICSFAIL ANDISTHEPRIMARYTREATMENTON%ARTHINANON REMOTESETTING)FTHEHEALTHMAINTE NANCEFACILITYISINCAPABLEOFPROVIDINGSURGICALCARE THEWORKERSANDSCIENTISTS AS WELLASTHEPUBLICMUSTBEAWAREOFTHEPOSSIBLECONSEQUENCES 4HE GOAL THEN IS TO PREVENT SURGERIES BY DETECTING THE PRESENCE OF POTENTIAL DISEASES(OWEVER MOSTCLINICALTESTSTODAYAREUSEDTOSCREENPATHOLOGYINPATIENTS 4HESETESTSHAVEAPOORABILITYFORDETECTINGDISEASEINVERYHEALTHYINDIVIDUALS)N ADDITION THEREARENOTESTSTHATAREDESIGNEDTOSELECT OUTTHEOCCURRENCEOFPATHOLOGY

Figure 7.3. In April 2010, Seven Crewmembers of the STS-131 Shuttle Mission Joined the Six Crewmembers of ISS Expedition-23. They Gathered for a Group Portrait in the Kibo Laboratory of the ISS. This Was the Largest Number of People in Space Ever. (Credit NASA).

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OVER THE NEXT  YEARS 4HIS IS A SERIOUS PROBLEM FOR SELECTING A CREW FOR A -ARS -ISSION;/SBORN = )N THE)NSTITUTEOF-EDICINEOFTHE.ATIONAL!CADEMYOF3CIENCESHADPUB LISHEDAREPORTONTHEMEDICALRISKSOFLONGMISSIONS4HENUMBERONECONCLUSIONBY THEINSTITUTEWASSOBERINGȃ3PACETRAVELISINHERENTLYHAZARDOUS4HERISKSTOHUMAN HEALTHONLONG DURATIONMISSIONSBEYONDLOW%ARTHORBIT IFNOTSOLVED REPRESENTTHE GREATESTCHALLENGETOHUMANEXPLORATIONOFDEEPSPACE ȄTHEREPORTSAID&URTHERMORE THEDEVELOPMENTOFSOLUTIONSȃISCOMPLICATEDBYTHELACKOFAFULLUNDERSTANDINGOFTHE NATUREOFTHERISKSANDTHEIRFUNDAMENTALCAUSESȄ 4HEAUTHORSOFTHISREPORT APANELOFMEDICALDOCTORS CLINICALPSYCHOLOGISTS ANDHEALTHCARESPECIALISTS WEREWELLAWARETHATDURINGSUCHMISSIONS ALLRISKSCOULD NOTBEPREDICTED4HEYPOINTEDOUTȃ4HESUCCESSESOFSHORT DURATIONSPACEMISSIONS MAY HAVE LED TO MISUNDERSTANDING OF THE TRUE RISKS OF SPACE TRAVEL BY THE PUBLIC 0UBLICUNDERSTANDINGISNECESSARYBOTHFORSUPPORTOFLONG DURATIONMISSIONSANDIN THEEVENTOFACATASTROPHEȄ4HEPUBLICMUSTBEPREPAREDFORTHEPOSSIBILITYTHATȃALL COUNTERMEASURESMAYTRAGICALLYFAIL THATACREWMAYNOTRETURNFROMAPROLONGEDMIS SION ORTHATINDIVIDUALSMAYNOTBEABLETOFUNCTIONPHYSICALLYORMENTALLYUPONTHEIR RETURNȄ THESTUDYGROUPWARNED )N A(UMAN2ESEARCH0ROGRAM(20 WASESTABLISHEDAT.!3!TOFOCUSON INVESTIGATINGANDMITIGATINGTHEHIGHESTRISKSTOASTRONAUTHEALTHANDPERFORMANCEIN SUPPORTOFEXPLORATIONMISSIONS4HEGOALOFTHE(20ISTOPROVIDEHUMANHEALTHAND PERFORMANCECOUNTERMEASURES KNOWLEDGE TECHNOLOGIES ANDTOOLSTOENABLESAFE RELI ABLE ANDPRODUCTIVEHUMANSPACEEXPLORATION4HESPECIʄCOBJECTIVESOFTHE(20ARE A TO MITIGATE THE HIGHEST RISKS TO CREW HEALTH AND PERFORMANCE 4ABLE  B TO IMPROVE HUMAN SPACEʅIGHT MEDICAL ENVIRONMENTAL AND HUMAN FACTORS STANDARDS C TOREDUCEHUMANSYSTEMSRESOURCEREQUIREMENTSMASS VOLUME POWER DATA AND D TOENSUREEFFECTIVEHUMAN SYSTEMINTEGRATIONACROSSEXPLORATIONMISSIONSYSTEMS

 !STRONAUTSELECTIONANDTRAINING  #REWPOSITION 4HEʄRSTASTRONAUTSANDCOSMONAUTSWEREJETAIRCRAFTPILOTS0HYSICALANDPSYCHOLOGI CALSCREENINGSWEREINTENSE DUETOTHEHAZARDOUSNATUREOFPIONEERINGMISSIONS4HEN THE PRIME EMPHASIS SHIFTED AWAY FROM ʅIGHT EXPERIENCE TOWARD SUPERIOR ACADEMIC QUALIʄCATIONS3OMEAPPLICANTSWEREINVITEDONTHEBASISOFTHEIREDUCATIONALBACK GROUND ALONE 4HESE WERE THE SCIENTIST ASTRONAUTS SO CALLED BECAUSE THE APPLICANTS

 !S$R!RNAULD.ICOGOSSIAN .!3!ȀSDIRECTOROFLIFESCIENCES HASPOINTEDOUTȃ.EVERBEFOREHASMEDI CINEBEENCALLEDUPONTOCERTIFYTHATANINDIVIDUALWILLBEHEALTHYENOUGHTOPERFORMFORTHREEYEARSFOLLOW INGTHEEXAMINATIONȄ;CITEDBY#OLLINS =  4HE#OLUMBIADISASTERSEEMSTOREVEALATRENDINTHEPUBLICACCEPTANCEOFSPACEFAILURES4HEGRIEFAND SADNESSWEREIMMENSEATTHENEWSOFTHETRAGEDY(OWEVER COMPAREDWITHTHE#HALLENGERTRAGEDYTHAT OCCURREDYEARSEARLIER WHICHALSOTOOKTHELIVESOFSEVENASTRONAUTS MUCHLESSINTERESTWASGIVENTOTHE INVESTIGATIONBYTHEMEDIAANDTHEPUBLICDURINGTHEWEEKSTHATFOLLOWED

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 Table 7.1.

List of the 27 Highest Risks to Human Health and Performance for Human Space Exploration Identified in the NASA Human Research Roadmap. Risks Include Physiological Effects from Radiation, Hypogravity, and Planetary Environments, as well as Unique Challenges in Medical Treatment, Human Factors, and Behavioral Health Support. Without Results of Studies Addressing These Issues, NASA Will Face Unknown and Unacceptable Risks for Mission Success and Post-mission Crew Health. Source: http://humanresearchroadmap.nasa.gov/.

Risk Factor of Inadequate Nutrition Risk of Acute and Late Central Nervous System Effects from Radiation Exposure Risk of Acute Radiation Syndromes Due to Solar Particle Events Risk of Adverse Behavioral Conditions and Psychiatric Disorders Risk of Adverse Health Effects Due to Alterations in Host-Microorganism Interactions Risk of Adverse Health Effects from Lunar Dust Exposure Risk of Bone Fracture Risk of Cardiac Rhythm Problems Risk of Compromised EVA Crew Health and Performance Due to Inadequate EVA Suit Systems Risk of Crew Adverse Health Event Due to Altered Immune Response Risk of Degenerative Tissue Or Other Health Effects From Radiation Exposure Risk of Early Onset Osteoporosis Due To Spaceflight Risk of Error Due to Inadequate Information Risk of Errors Due to Poor Task Design Risk of Impaired Control of Spacecraft, Associated Systems and Immediate Vehicle Egress Due to Vestibular/Sensorimotor Alterations Associated with Space Flight Risk of Impaired Performance Due to Reduced Muscle Mass, Strength and Endurance Risk of Inability to Adequately Recognize or Treat an Ill or Injured Crewmember Risk of Intervertebral Disk Damage Risk of Orthostatic Intolerance During Re-Exposure to Gravity Risk of Performance Decrement and Crew Illness Due to an Inadequate Food System Risk of Performance Decrements Due to Inadequate Cooperation, Coordination, Communication, and Psychosocial Adaptation within a Team Risk of Performance Errors Due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness, and Work Overload Risk of Radiation Carcinogenesis Risk of Reduced Physical Performance Capabilities Due to Reduced Aerobic Capacity Risk of Reduced Safety and Efficiency Due to an Inadequately Designed Vehicle, Environment, Tools or Equipment Risk of Renal Stone Formation Risk of Therapeutic Failure Due to Ineffectiveness of Medication

WHOMETMINIMUMREQUIREMENTSHADADOCTORATEOREQUIVALENTEXPERIENCEINTHENATU RALSCIENCES MEDICINE ORENGINEERING 3INCETHEʄRSTSELECTIONOFSEVEN53ASTRONAUTSFORITS-ERCURYPROGRAM .!3! HASSELECTEDMOREGROUPSOFASTRONAUTS4HEʄRSTASTRONAUTSWEREMILITARYPILOTS

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4HEʄRSTGROUPOFASTRONAUTCANDIDATESFORTHESPACESHUTTLEPROGRAMWASSELECTEDIN *ANUARY AND INCLUDED SCIENTISTSAND PILOTS 3IX OFTHE  WEREWOMEN 3INCETHEN CANDIDATESWERESELECTEDASNEEDED NORMALLYEVERYYEARS4HEBACK GROUNDS OF .!3!ȀS LATEST GROUP OF ASTRONAUT CANDIDATES SELECTED IN  INCLUDE SCHOOLTEACHERS DOCTORS SCIENTISTS ANDENGINEERS 0ILOT ASTRONAUTS SERVE AS SPACE SHUTTLE OR 3OYUZ COMMANDERS AND PILOTS "OTH CIVILIANANDMILITARYPERSONNELARECONSIDEREDFORTHEPROGRAM$URINGTHEʅIGHT THE COMMANDER HAS ONBOARD RESPONSIBILITY FOR THE VEHICLE CREW MISSION SUCCESS AND SAFETYOFʅIGHT4HEPILOTASSISTSTHECOMMANDERINCONTROLLINGANDOPERATINGTHEVEHI CLEANDMAYASSISTWITHROBOTICSOPERATIONS .!3!-ISSION3PECIALIST-3 ASTRONAUTSAND2USSIAN&LIGHT%NGINEER&% COS MONAUTSWORKWITHTHECOMMANDERANDHAVEOVERALLRESPONSIBILITYFORCOORDINATING ONBOARD OPERATIONS IN THE FOLLOWING AREAS VEHICLE SYSTEMS CREW ACTIVITY PLANNING CONSUMABLESUSAGE ANDEXPERIMENTOPERATIONS-3AND&%ARETRAINEDINTHEDETAILSOF THEONBOARDSYSTEMS ASWELLASTHEOPERATIONALCHARACTERISTICS MISSIONREQUIREMENTS ANDOBJECTIVES ANDSUPPORTINGEQUIPMENTFOREACHOFTHEEXPERIMENTSCONDUCTEDON THEIR ASSIGNED MISSIONS -3 AND &% PERFORM EXTRA VEHICULAR ACTIVITIES OPERATE THE ROBOTICARMS ANDARERESPONSIBLEFORPAYLOADSANDSPECIʄCEXPERIMENTOPERATIONS 0AYLOAD3PECIALISTSWEREPERSONSOTHERTHAN.!3!ASTRONAUTSWHOHADSPECIALIZED ONBOARDDUTIES4HEYWEREADDEDTOSHUTTLECREWSIFACTIVITIESTHATHADUNIQUEREQUIRE MENTSWEREINVOLVEDANDMORETHANTHEMINIMUMCREWSIZEOFʄVEWASNEEDED0AYLOAD 3PECIALISTSWERESELECTEDBASEDONTHEIRSCIENTIʄCORTECHNICALSKILLSEG ONEOFTHE NEUROSCIENTISTSWORLDWIDEWHOWASABLETOPERFORMAMICRONEUROGRAPHYONTHENERVE OFALEGMUSCLEATTHETIMEʅEWAS0AYLOAD3PECIALISTDURINGTHE.EUROLABMISSIONIN  )NVITEDORPAYINGGUESTSFORAGIVENMISSION SUCHASPOLITICIAN JOURNALIST SCIEN TIST ANDTEACHER0AYLOAD3PECIALISTSHAVEALSOBEENCLASSIʄEDAS0AYLOAD3PECIALISTS 4HEDEVELOPMENTOFCOMMERCIALSPACEʅIGHTACTIVITIESHASCREATEDTWOOTHERTYPES OFASTRONAUTS#OMMERCIAL!STRONAUTSAND3PACEʅIGHT0ARTICIPANTS5NLIKETHECURRENT ASTRONAUTSANDCOSMONAUTSWHOAREGOVERNMENT EMPLOYEDANDTRAINEDTOʅYONSPE CIʄCSPACECRAFTLIKETHESPACESHUTTLE 3OYUZ ANDTHE)33 #OMMERCIAL!STRONAUTSARE ANY PROFESSIONAL ASTRONAUTS TRAINED TO ʅY ON PRIVATELY OWNED SPACE VEHICLES 3PACEʅIGHT0ARTICIPANTS MORECOMMONLYCALLEDȃSPACETOURISTSȄ AREPEOPLEWHOPAY FORTHESPACEʅIGHTEXPERIENCEDURINGORBITALORSUBORBITALʅIGHTSANDDONOTPROVIDEA RECURRINGSERVICEASCAREERASTRONAUTS)NANYCASE THESEINDIVIDUALBECOMEOFʄCIAL ASTRONAUTSWHENTHEYREACHANALTITUDEOFKM&IGURE  

0HYSICALREQUIREMENTSFORASTRONAUTSELECTION

!LLAPPLICANTSMUSTMEETCERTAINPHYSICALREQUIREMENTSANDMUSTPASSPHYSICALEXAMI NATIONSWITHVARYINGSTANDARDSDEPENDINGONCLASSIʄCATION4ABLE 

 4HEʄRST#OMMERCIAL!STRONAUTTOʅYAPRIVATESPACECRAFTWAS-IKE-ELVILLE WHOWASTHEPILOTDURING THEʅIGHTOF3PACE3HIP/NEIN  !STRONAUTSARESELECTEDFORHEALTHSPACETOURISTSARESELECTEDFORWEALTH

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Figure 7.4. Mission and Payload Specialists Are Performing Specific Intra- or ExtraVehicular activities. In This Photograph, CSA Mission Specialist Dave Williams Is Being Equipped for Recording His Brain Activity During the Neurolab STS-90 Life Sciences Mission. (Credit NASA). Table 7.2.

Medical Requirements for NASA Class I, II, III and IV Astronaut Applicants. The Requirements for Spaceflight Applicants are for the Passengers of Orbital Flight to the ISS.

Item

Pilots (Class I)

Mission Specialist (Class II)

Payload Specialist (Class III)

Participants to Spaceflight (Class IV)

Distant vision

20/50 or better uncorrected; correctable to 20/20 each eye

20/150 uncorrected; correctable to 20/20 each eye

Correctable to best eye

Same as Class III

Near vision

Uncorrected 8; hyper > 2

Eso > 15; exo > 8 Not specified Not specified; hyper > 2

Depth perception

No errors in 16 presentations of the Verhoeff stereopter Test

Same as Class I Not specified Not specified

Color vision

Pass Farnsworth lantern Test

Pass Farnsworth lantern Test

Not specified Not specified

Blood pressure

140/90

140/90

150/90 allowed