Ar#ficial Gravity Studies on Board the DSH
Transcript of Ar#ficial Gravity Studies on Board the DSH
Ar#ficialGravityStudiesonBoardtheDSH
30Jan2017
GillesClement
Ar#ficialGravityStudyKickoffMee#ng
NASAJohnsonSpaceCenterBuilding15/Room267
Ar#ficialGravity(AG)Poten#alBenefits
• BeHertopreventissuesratherthantoapplycountermeasuresaIerthefact.
• AGproducesmul#-systemeffects.
• AGisapoten#alcountermeasureforVIIP(VisualImpairmentIntracranialPressure)syndrome.
• AGreducescountermeasurerequirementsaIerlandingonplanetarysurface.
• Rehabilita#onstarts6monthsearlierthananon-AGmission,andiscompletewhencrewreturnstoEarth.
NASAHRP–HumanRisksofSpaceflight
AlteredGravityLevel• Visionaltera#ons• Renalstoneforma#on• Sensorimotoraltera#ons• Bonefracture• Impairedperformance• Reducedaerobiccapacity• Adversehost-microorganisminterac#ons
• Urinaryreten#on• Orthosta#cintolerance• Backpain• Cardiacrhythmproblems• Effectsofmedica#on• Intervertebraldiskdamage
GroupedbyHazards–30Risks&2Concerns
Radia#on• Exposuretospaceradia#on
DistancefromEarth• Limitedin-flightmedicalcapabili#es
• Toxicmedica#ons
Isola#on• Adversecogni#veorbehavioralcondi#ons
• Performance&behavioralhealthdecrements
Hos#le/ClosedEnvironment–SpacecraJDesign
• CO2exposure• Inadequatefood/nutri#on• Inadequatehuman-systeminterac#ondesign
• Injuryfromdynamicloads• InjuryduringEVA• Celes#aldustexposure• Alteredimmuneresponse• Hypobarichypoxia• Sleeploss&workoverload• Decompressionsickness• Toxicexposure• Hearingloss• Sunlightexposure
Riskspoten#allyminimizedbyar#ficialgravity
WhyHasAGNeverBeenImplemented?
• Lackofdefini#vedesignrequirements,especiallyacceptableAGlevelsandrota#onrates.
• Percep#onofhighvehiclemassandperformancepenal#es.
• Expecta#onofeffec#vecrewmicrogravitycountermeasures.
• Spaceresearchfocusonmicrogravity,notpar#algravity.
ROCKY–Aerobicac#vityandstrengthtrainingdevelopedforOrion.
HRPAr#ficialGravityProject
Goal– DeterminethedesigntradespaceassociatedwithAGforMarsmissionsvehiclesandhabitats.
Objec#ves– Implementanevidence-based,peer-reviewed,coordinatedR&Dprojecttoinves#gateAG.
– Determinetheop#maldesigncharacteris#csforanAGcountermeasure.
Milestone– CriteriafordecidingwhetherAGcanprotectcrewhealthandperformanceduringhumandeepspacemissionsareexpectedNET2022.
HumanHealthandCountermeasuresElement
EM/DEM:Baumann/VillarrealES/DES:Norsk/Barr
ESC:K.George
InadequateNutri#on
S.Smith/Zwart
SensoryMotorAltera#ons
Bloomberg
PK/PDconcernVacant
ExerciseRyder/Downs
Impairedperfduetoreducedmusclemass,strengthandenduranceReducedphysicalperfcapabilityduetoreducedaerobiccapacity
BoneSibonga
EarlyonsetosteoporosisIVDconcern
ImmuneResponseCrucian/Kunz
Transla#onalResearchARC/AlwoodJSC/Wu
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Micro-GravityInducedVisualAltera#ons/ICPStenger/Laurie
CARDIOVASCULARANDVISIONPORTFOLIO
Allcorn
EXERCISEANDPERFORMANCEPORTFOLIO
H.Paul
MULTISYSTEMPORTFOLIOPloeger
DigitalAstronautGilkey/
Lewandowski
TECHNOLOGYANDINFRASTRUCTUREPROJECTSPORTFOLIO
BaumannPSC:Taylor
PSC:K.G
eorge
PSC:S.Smith
CardiovascularStenger/S.Lee
CardiacRhythmProblemsOrthosta#cIntolerance
CROSSDISCIPLINEINTEGRATION
Explora#onExerciseHaven/Perusek
DeWiV/LewandowskiPSC:K
.Geo
rge
PSC:A
llcorn(ac#ng)
Ar#ficialGravityCountermeasure
Clement
EVAAbercromby/NorcrossDCSEVAHealth&PerformanceExpAtm
AdvancedFoodDouglas
MicroHostOubre/OV
StandinginaRota#ngSpacecraI
ω
ω
StandingonEarth
1 G
1 G
1 G
r
For1g(±3%):r>60mω<4rpm
(rota#onrate)
(radius)
Rota#onofpartofthevehiclee.g.Nau#lus-Xr=6mω=12rpm
Onboardcentrifugee.g.AGREEr=1.6mω=42rpm(1gatheart)
Rota#onofthewholevehiclee.g.MarsNTRr=56mω=4rpm
• AG=(ωveh)2r
• Lineartransla#on(v)ofthewholebodyorbodypartsalonganaxisthatisnotparalleltothespinaxiswillcreateaCoriolisforce: -2m(ωve
hv)
• Angularmovements(ωbody)oftheheadthatisnotparalleltothespinaxiswillcreatecross-coupledaccelera#ons: ωbody ωvehcos(A)
AG
Lackner&Dizio(2000)
PhysicsofCentrifuga#on
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CoriolisForce–Principle
ω
v
-2m (ωv)
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RWStone(1973)AnOverviewofAr#ficialGravity.NASASP-314
CoriolisForceduringLocomo#on
Ves#bularOrgans
Lackner&DiZio(2005)
Cross-CoupledAngularAccelera#ons
• Theyawsemicircularcanals arebroughtoutoftheplane ofrota#on,andreceivean angularvelocityimpulse.
• Thepitchsemicircularcanalsares#mulatedbyheadpitch.
• Therollver#calsemicircularcanalsarebroughtintotheplaneofrota#on,andreceiveanangularvelocityimpulse.
Whenasubject#ltshisheadforwardduringpassiveyawconstant-velocityrota#on:
• Theotolithorgansares#mulatedbyradial(centripetal)andtangen#al(Coriolis)linearaccelera#ons,andsignalareorienta#onoftheheadinrela#ontothegravito-iner#alver#cal.
Cross-CoupledAngularAccelera#ons
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1 g
ω
0.16 g 2.3 g
GravityGradient
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0.16 g
1 g
2.3 g
Short-RadiusCentrifuga#oninSpaceStandingonEarth
1 g
1 g
1 g
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GravityGradient
0.16g
ω=33RPM
2.3g1g
0.95g
ω=11RPM
1.2g1g
Gravitygradient=(2.3-0.16)/2.3=93.4%
Gravitygradient=(1.2-0.95)/1.2=20.1%
r=1.9m
r=8.8m
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1 g
ω
0.16 g 2.3 g
Short-RadiusCentrifuga#oninSpace
1 g
1 g
ω
0.16 g 2.3 g
1 g1 g
Short-RadiusCentrifuga#ononEarth
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Short-RadiusCentrifuga#ononEarth
1 g1 g
1 g
-6ºHead-DownBedRest
SRCentrifuga#oninSpace
1 g
1 g
ω
0.16 g2.3 g
1 g1 g
0.16 g
1 g
2.3 g
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• Rota#onstudies(Graybiel1960-1965)– Slowrota#ngroom(SRR)–2.3-mradius– SRRacceleratedfromrestto1,1.71,2,
2.21,3.82,5.44,7.5&10rpm(single-step)– Below3.82rpmadapta#ontookplaceinminutes.– At3.82rpmadapta#ontookplaceinhours.– At5.44and7.5rpmallsubjectswerepar#ally
incapacitatedbymo#onsickness,disrup#onofmovementcontrol,andfa#gue.Consequently,theygreatlyreducedtheirmovementandspentmuch#mesleeping.
– At10rpmallsubjectswereseverelyincapacitatedbymo#onsicknessandfa#gue,andneverwereabletomakenormalheadandbodymovements.
• OnthebasisofthesestudiesitisoIenclaimedthatrota#onrateforAGshouldbe4rpmorbelow.
Adapta#ontoRota#ngEnvironments
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• SRRstudiesinthe1960s:– Werepreliminaryandinvolvedatotalofonly30subjects– DidnotaHempttoiden#fyop#mumexposureand
trainingstrategiestoadaptpeopletorota#ngenvironments
• Sincethen,itwasfoundthat:– Nomo#onsicknessisexperiencedwhenrota#onrateis
achievedincrementally,e.g.in1-rpmstepsormore(Graybiel&Knepton1978;Youngetal.2001)
– Mo#onsicknessdecreasesaIerrepeatedexposuretocross-coupledaccelera#ons(Clémentetal.2001)
– Adapta#onofarm,leg,andheadmovementcontroltorota#onratesof10rpmandhigher(Lackner&Dizio2000)
Adapta#ontoRota#ngEnvironments(cont’d)
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• Concern#1:WhethertheresponsestoCoriolisandcross-coupledaccelera#onsandtheabilitytoachieveadapta#onwillbethesamein0gasin1g– SkylabM-131foundthatheadmovementsmadeduring
rota#onfailedtoinducedmo#onsicknessonorbit– Inparabolicflight,sideeffectsaremoresevereat2gand
lessintenseat0gthanin1g.– Inparabolicflight,devia#onofmovementpathsimilarat
0g,1g,and2g.
Adapta#ontoRota#ngEnvironments(cont’d)
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GraybielA,MillerEF,HomickJL(1977)ExperimentM131.Humanves#bularfunc#on.In:JohnstonRS,DietleinLF(eds)BiomedicalResultsfromSkylab.NASA:WashingtonDC,NASASP-377,pp74-103
SkylabExperimentM131
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• Concern#2:Whetheradapta#ontoSRRonEarth,whereAGisalmostparalleltorota#onaxis,willtransfertorota#onofaspacevehicle,whereAGwillbeorthogonaltothespinaxis:– Bodymovementsmadefromastar#ngpostureparallelvs.
orthogonaltothespinaxisgeneratedifferentCoriolisandcross-coupledaccelera#ons
– Mo#onsicknessadapta#ontransferredbetweenbodyorienta#ons,butwalkingdidnot(Graybieletal.1968)
Adapta#ontoRota#ngEnvironments(cont’d)
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Model–somevalida#onrequired
Stone&Letko(1965) 25
• Ar#ficialgravitywasfirsttestedonhumansinspacein1966duringtheGemini-11flight
– ThespacecraIwastetheredtoanAgenatargetvehiclebyalongDacronline,causingthetwovehiclestospinslowlyaroundeachother(r=200m,ω<1rpm,AG<0.001g)
– AccordingtotheGeminicommander,aTVcamerafell“down”inthedirec#onofthecentrifugalforce,butthecrewdidnotperceiveanychanges
AGwithHumans–WhatDoWeKnow?
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WhatDoWeKnow?(cont’d)• Ves#bularinves#ga#onson
boardSTS-42(IML-1,1992)– NASASpacelabRotator–PI:MReschke(NASA)
– Axisofrota#onalignedwithsubject’scenterofmass.Headandfeetwereoff-centerbyabout0.6m
– Rota#onat20rpmforoneminutegeneratedacentripetalaccelera#onof0.22g
– +Gzatthefeet– –Gzatthehead
NASASpacelabRotator
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WhatDoWeKnow?(cont’d)• Ves#bularinves#ga#onson
boardSTS-90(Neurolab,1998)– ESAOff-AxisRotator–PI:GClément(CNRS)
– Gycentrifuga#on–Subjectoff-centerby0.5m
– Gzcentrifuga#on–Axisofrota#onalignedwithsubject’scenterofmass(r=0.65m)
– Rota#onat42rpmfor7mingenerated+1.0Gy(body)
– Rota#onat37rpmfor7mingenerated+1.0Gzatfeetand–1.0Gzathead
28ESAOff-AxisRotator
• “Gdose-physiologicalresponse”curve– Acutestudies–rats(suspension)&humans(parabolicflight,unloading)– Chronicstudies–mice(JAXAISScentrifuge)
• Dura#onofAGexposure– Con#nuous–rats(ground-basedcentrifuge)– Con#nuous–mice(JAXAISScentrifuge)– IntermiHent–humans(bedrest)
• HealthconsequencesofAG– Cross-coupledandCoriolisaccelera#ons(SRR)– Gravitygradient(large-radiuscentrifuge)– Combina#onwithexercise
• Valida#onofAGprescrip#oninorbit– Models– Comparisonbetweengroundandon-orbitAGprescrip#on–mice– FlightAGdemonstra#onwithhumans–HTV-X– FlightAGvalida#onwithhumans–DSH
AGResearchApproach
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HRPAGResearchPlan(Jan2017)
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HRPAGResearchPlan(Jan2017)
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SupportStructureAssembly
MotorAssembly
ISSAGREEProject(2011)
1.4gat30rpm
0.8gat30rpm
0.3gat30rpm
0.1gat30rpm
0.2gat30rpm
ISSAGREEGravityGradient
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HTV-XHumanCentrifugeProject
Pressurizedmodule
Unpressurizedmodule
ISS
HTV-X
?
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HTV-XHumanCentrifugeObjec#ves• Subjec#veAssessment– Crewcomfort–nominalandmaxRPM– Safetyissues– Crew#me– Crewoverallacceptance
• EngineeringAssessment– Loadsatinterfaceswithmodule/node– Vibra#ons,gjiHers,noise– Heatload– Airflow
• PhysiologicalAssessment–AGasacountermeasure– CompareCEVISandcentrifuge– E.g.,CEVISduringfirsthalfofExpedi#on,centrifugeduringsecondhalfofExpedi#on(vice-versawith2ndsubject)
CEVIS
SpinningTrack
• Radius:3.3m• Rota#onrate:6.5rpm- 0.15gatfeet
Skylab2(1973)• Radius:5m• Trackrota#onrate:6rpm• Subjectrota#onrate:9rpm- 1gatcenterofmass- 1.3gatfeet