IceGiantsPre-DecadalStudySummary
CAPSMeeting,29March2017
AmySimon(NASAGoddardSpaceFlightCenter)MarkHofstadter(JetPropulsionLaboratory,CaliforniaInstituteof
Technology)andtheIceGiantStudyTeam
1Predecisional - Forplanninganddiscussionpurposesonly.URSCL#265147 ©2017AllrightsReserved
Predecisional - Forplanninganddiscussionpurposesonly.URSCL#265147
StudyGoalandObjectivesGoal• Assessscienceprioritiesandaffordablemissionconcepts&optionsforexplorationoftheIceGiantplanets,UranusandNeptuneinpreparationforthenextDecadalSurvey.
Objectives• Evaluatealternativearchitecturestodeterminethemostcompellingsciencemission(s)thatcanbefeasiblyperformedwithin$2B($FY15)• Identifypotentialconceptsacrossaspectrumofpricepoints
• Identifymissionconceptsthatcanaddressscienceprioritiesbasedonwhathasbeenlearnedsincethe2013–2022DecadalSurvey
• Identifyenabling/enhancingtechnologies
• AssesscapabilitiesaffordedbySLS
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KeyStudyGuidelines(ExcerptedfromStudyGuidelinesDocument)• EstablishaScienceDefinitionTeam• AddressbothUranusandNeptunesystems• Determinepros/consofusingonespacecraftdesignforbothmissions(possibilityofjointdevelopmentoftwocopies)
• Identifymissionsacrossarangeofpricepoints,withacostnottoexceed$2B($FY15)permission
• Performindependentcostestimateandreconciliationwithstudyteam• Identifymodelpayloadforaccommodationassessmentforeachcandidatemission.
• ConstrainmissionstofitonacommercialLV• Alsoidentifybenefits/costsavingsifSLSwereavailable(e.g.,time,traj.,etc.)
• Launchdatesfrom2024to2037(focusonthenextdecadalperiod)• Evaluateuseofrealisticemergingenablingtechnologies;distinguishmissionspecificvs.broadapplicability
• Identifycleaninterfacerolesforpotentialinternationalpartnerships
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WhyUranusandNeptune?• Theserelativelyunexploredsystemsarefundamentallydifferentfromthegasgiants(JupiterandSaturn)andtheterrestrialplanets- UranusandNeptuneare~65%waterbymass(plussomemethane,ammoniaandotherso-called“ices”).Terrestrialplanetsare100%rock;JupiterandSaturnare~85%H2andHe
• Icegiantsappeartobeverycommoninourgalaxy;mostplanetsknowntodayareicegiants• Theychallengeourunderstandingofplanetaryformation,evolution,andphysics- Modelssuggesticegiantshaveanarrowtimewindowforformation.Ifcorrect,whyaretheysocommoninotherplanetarysystems?
- WhyisUranusnotreleasingsignificantamountsofinternalheat?Doesitsoutputvaryseasonally?
- Whyaretheicegiantmagneticfieldssocomplex?Howdotheunusualgeometriesaffectinteractionswiththesolarwind?
!
Uranusin2012(Sromovskyetal.2015)and1986(right,Voyager)
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12KeyScienceObjectives
PlanetaryInterior/Atmosphere• Planetarydynamo• Atmosphericheatbalance
• Tropospheric3-Dflow
Rings/Satellites• Internalstructureofsatellites• Inventoryofsmallmoons,includingthoseinrings
• Ringandsatellitesurfacecomposition
• Ringstructuresandtemporalvariability
• Shapeandsurfacegeologyofsatellites
• Triton’satmosphere:origin,evolution,anddynamics
Magnetosphere• Solarwind-magnetosphere-ionosphereinteractionsandplasmatransport
HighestPriority• Interiorstructureoftheplanet• Bulkcompositionoftheplanet(includingisotopesandnoblegases)
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UranusorNeptune?• UranusandNeptunesystemsareequallyimportant
• AFlagshipmissiontoeitherisscientificallycompelling
• Itisimportanttorecognize,however,thatUranusandNeptunearenotequivalent.Eachhasthingstoteachustheothercannot.Forexample- Nativeice-giantsatellites(Uranus)vs.capturedKuiper
Beltobject(Neptune)- Thesmallest(Uranus)andlargest(Neptune)releasesof
internalheat,relativetoinputsolar,ofanygiantplanet- Dynamicsofthin,denseringsanddenselypacked
satellites(Uranus)vs.clumpyrings(Neptune)
Uranus(top,Sromovskyetal.2007)andNeptune(bottom,Voyager)
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ModelPayloadsChosentomaximizesciencereturn. SimilarforUranusandNeptune.
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Modelpayloadforprobe:• Massspectrometer• ASI(density,pressureandtemperatureprofile)• Hydrogenortho-parainstrument• Nephelometer
Modelpayloadfororbiterorflybys/c
50kgorbiterpayloadaddressesminimumacceptablescience• NAC,• DopplerImager,• Magnetometer.
90kgorbiterpayloadpartiallyaddresseseachscienceobjective.Addto50kgcase:• Vis/NIR imagingspect.,• RadioandPlasmasuite,• ThermalIR,• Mid-IRorUVspect.
150kgorbiterpayloadcomprehensivelyaddressesallscienceobjectives.Addto90kgcase:• WAC,• USO,• EnergeticNeutralAtoms,• Dustdetector,• Langmuirprobe,• Radiosounder/Massspec.
Predecisional - Forplanninganddiscussionpurposesonly.URSCL#265147
MissionArchitectures• Widerangeofarchitecturesassessed;rankedscientificallyandcosted
• Anorbiterwithprobemeetsthesciencerequirementsandstudycosttarget
• Addingasecondspacecrafttotheothericegiantsignificantlyenhancesthesciencereturnataproportionallyhighercost
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GettingtotheIceGiants• Launchintervalstudied:[2024– 2037]
• Totalmissionduration<15yearsincludingatleast2yearsofscience
• Interplanetaryflighttime:• 6– 12yearstoUranus• 8– 13yearstoNeptune
LaunchVehicles
•AtlasV•Delta-IVHeavy•SLS-1B
InterplanetaryTrajectory
•Chemical+DSM+GA•SEP+GA•REP+GA•DualSpacecraft
GravityAssist(upto4perTraj.)
•Venus•Earth•Mars•Jupiter•Saturn
TargetBodies
•Uranus•Neptune
SEPPower
•15kW•25kW•35kW
EPEngines
•NEXT1+1(SEP)•NEXT2+1(SEP)•NEXT3+1(SEP)•XIPS(REP)
OrbitInsertion
•Chemical(Bi-Prop)•Chemical(cryo)•REP•Aerocapture
• Tensofthousandsoftrajectoryoptionstobothplanetswereexamined• Orbitinsertion∆VatbothUranusandNeptuneishigh
Neptune:2.3-3.5km/sUranus:1.5-2.5km/s
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MissionDesignTakeaways• Launchesarepossibleanyyearstudied(2024-2037)
• Optimallaunchopportunitiesarein2029-2032,usingJupitergravityassist• MissionstoUranusviaSaturnarepossiblethroughmid-2028• NoNeptuneviaSaturntrajectoriesinthestudytime-range
• Chemicaltrajectoriesdeliveraflagship-classorbiter(>1500kgdrymass)toUranusin<12yearsusingAtlasV• Delta-IVHeavycanreduceinterplanetary
flighttimeby1.5years
• Nochemicaltrajectoriesexistfordeliveringaflagship-classorbitertoNeptunein<13yearsusingAtlasVorDelta-IVHeavylaunchvehicles.SLSorLongerflighttimeswouldbeneeded.
• SEPEnablesaflagshiporbitertoNeptunein12-13years• Implementedasseparablestagetominimizepropellantrequiredforinsertion
EVEEJU
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BenefitsofSLSAllsingleplanetmissionsstudiedareachievablewithexistingELVs
SLScanprovideenhancingbenefits:• Increasesdeliverablemassandlowersflighttimeby3to4years
• EnableschemicalNeptunemissionin11.5yr.• Enablestwospacecraftmissionswithasinglelaunch
• Increaseslaunchopportunities
Whencombinedwithaerocapturecapability,enablesverylowflighttimesforbothUranus(<5yr.)andNeptune(<7yr.)
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MissionConceptPointDesigns
FourbasicmissionconceptsweretakenthroughTeamXforpointdesignandcosting.Theseconceptswerechosentoconstrainthescience/costparameterspace:
• Uranusorbiterwith~50kgpayloadandatmosphericprobe• Uranusorbiterwith~150kgpayloadwithoutaprobe• Neptuneorbiterwith~50kgpayloadandatmosphericprobe• Uranusflybyspacecraftwith~50kgpayloadandatmosphericprobe
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Keyarchitecturesfullyassessedusingcommonbuildingblocks
NeptuneOrbiterwithProbe,SEP,and50kgpayload
UranusFlybywithProbeand50kgpayload
UranusOrbiterwithProbeand50kgpayload
UranusOrbiterwith150kgpayload
Launchmass:7364kg
Launchmass:1525kg Launchmass:
4345kg Launchmass:4718kg
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ConceptSummary
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CaseDescription
NeptuneOrbiterwithprobeand<50kgsciencepayload.IncludesSEPstage forinnersolarsystemthrusting.
UranusFlybyspacecraftwithprobeand<50kgscience
payload
UranusOrbiterwithprobeand<50kgsciencepayload.
Chemicalonlymission.
Uranus Orbiterwithoutaprobe,butwith150kg
sciencepayload.Chemicalonlymission.
ScienceHighestpriorityplus
additionalsystemscience(rings,sats,magnetospheres)
Highestpriorityscience(interiorstructureand
composition)
Highestpriorityplusadditionalsystemscience
(rings,sats,magnetospheres)Allremotesensingobjectives
TeamXCostEstimate*($k,FY15) 1971 1493 1700 1985
AerospaceICE($k,FY15) 2280 1643 1993 2321
Payload 3instruments†+atmosphericprobe
3instruments†+atmosphericprobe
3instruments†+atmosphericprobe 15instruments‡
PayloadMassMEV(kg) 45 45 45 170LaunchMass(kg) 7365 1524 4345 4717
LaunchYear 2030 2030 2031 2031FlightTime(yr) 13 10 12 12
TimeinOrbit(yr) 2 Flyby 3 3TotalMissionLength(yr) 15 10 15 15
RPS use/EOMPower 4eMMRTGs/376W 4eMMRTGs/425W 4eMMRTGs/376W 5eMMRTGs/470WLV DeltaIVH+25kWSEP AtlasV541 AtlasV551 AtlasV551
PropSystem DualMode/NEXTEP Monopropellant DualMode DualMode
*IncludescostofeMMRTGs,NEPA/LA,andstandardminimaloperations,LVcostnotincluded†includesNarrowAngleCamera,DopplerImager,Magnetometer‡includesNarrowAngleCamera,DopplerImager,Magnetometer,Vis-NIRMapping Spec.,Mid-IRSpec.,UVImagingSpec.,PlasmaSuite,ThermalIR,EnergeticNeutralAtoms,DustDetector,LangmuirProbe,MicrowaveSounder,WideAngleCamera
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CostSummary,KeyArchitectures
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Description
NeptuneOrbiterwithprobeand50kgsciencepayload(requiresSEPstage)
UranusFlybyspacecraftwithprobeand50kgsciencepayload
UranusOrbiterwithprobeand50kgsciencepayload
Uranus Orbiterwithoutaprobe,and150kgscience
payload
TeamXCostEstimates($k,FY15)TotalMissionCost* 1971 1493 1700 1985
AerospaceICE($k,FY15)TotalMissionCost* 2280 1643 1993 2321
*IncludescostofeMMRTGs,NEPA/LA,andstandardoperations. LVcostnotincluded.
• Neptunemissionscost~$300MmorethanUranusforcomparablesciencereturn(drivenbySEP)
• TheUranusorbiterwithprobemissionisestimatedtobeintherangeof$1.7to$2.6Bdependingontheorbiterpayload(50-150kgrange)andreserveposture
The cost information contained in this document is of a budgetary and planning nature and is intended for informational purposes only. It does not constitute a commitment on the part of JPL and/or Caltech
Predecisional - Forplanninganddiscussionpurposesonly.URSCL#265147
NewTechnologiesConsideredMissionenhancing,butnotrequired• InSpaceTransportation
• Aerocapture• LOX-LH2chemicalpropulsion• RadioisotopeElectricPropulsion(REP)
• OpticalCommunicationsBeyond3AU
• Smallsatellites
• AdvancedRadioisotopePower• SegmentedModularRadioisotopeThermoelectricGenerator(SMRTG)• HighPowerStirling RadioisotopeGenerator(HPSRG)
Enabling• eMMRTG radioisotopepowersystem• HEEET thermalprotectionsystem• Giantplanetseismometer(e.g.DopplerImager)
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• IceGiantsconceptscanbeimplementedwitheMMRTG andHEEETtechnologycurrentlyindevelopment.GPseismologyisanopportunityforground-breakingscience.
Predecisional - Forplanninganddiscussionpurposesonly.URSCL#265147
StudyRecommendations• AnorbiterwithprobebeflowntoUranus,launchingnear2030• AUranusorNeptuneorbitershouldcarryapayloadbetween90and150kg
• Two-planet,two-spacecraftmissionoptionsshouldbeexplored• ThedevelopmentofeMMRTGs andHEEET isenablingandshouldbecompletedasplanned
• Thereshouldbecontinuedinvestmentsinground-basedresearch(theoreticalandobservational)andinstrumentation.Importantareasincludeupper-atmosphericproperties,ring-particleimpacthazard,andgiant-planetseismology
• Internationalcollaborationsshouldbeleveragedtomaximizethesciencereturnwhileminimizingthecosttoeachpartner
• Anadditionalmissionstudyshouldbeperformedthatusesrefinedprogrammaticground-rulestobettertargetthemissionlikelytofly
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AnIceGiantMissionin2030
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Whyshouldwebeexcitedaboutthispossibility?• Thismissionengagesalldisciplinesintheplanetarysciencecommunity,aswellasheliophysics andexoplanetscientists
• LaterlauncheslosetheopportunitytomaptheNorthernHemispheresoftheUraniansatellites,andsampleuniquesolarwindgeometries
• Themissionrequiresnonewtechnology,andislow-risk
• CompletestheDecadalSurvey'srecommendedFlagshipmissions
• Partners,especiallyESA,areinterestedincost-sharing
Ó Woods Whole Oceanographic Institute & Kevin Hand
Backup
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InternationalPartnerships• Abroadoptionspaceexistsforinternationalpartnerships- Scientists- Instruments- Probes- Spacecraftorspacecraftsubsystems- Groundstations- Possiblesecondspacecraftoneitherasharedorseparatelaunchvehicle
• ESAreceivedabriefingon31January- TheywillproposeamechanismfortheirparticipationinanIceGiantFlagship
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ScienceObjectivesSummary• AllelementsoftheIceGiantsystems(interior,atmosphere,rings,satellites,magnetosphere)haveimportantscienceobjectivesthatcannotbemetthroughEarth-basedobservations
• Determiningtheinteriorstructureandbulkcompositionoftheicegiantsisidentifiedasthehighest-payoffscience
• Scientificandtechnologicaladvances,andimprovedtrajectories,makethesemeasurementshigherprioritythanintheDecadalSurvey
• 12keyscienceobjectivesdrivemissionarchitectures(nextslide)
• Allscienceobjectivesareconsistentwithandtraceabletothedecadalsurvey
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SEPTradespaceExample
• UsefulInsertedMass=MassafterOrbitinsertion– PropellantTanks• Thecoloredlegenddepictsinterplanetaryflighttimeinyears.Notethatthecolorsareuniquetoeachplot.• Tradespacehighlightshighperformingtrajectories,backuplaunchopportunitiesandallowsustopicka
baselinemissiontrajectoryforfurtherrefinementsFiguresshownareforDelta-IVheavylaunchvehiclewith25kWSEPstageonly
25 26 27 28 29 30 31 32 33 34 35 36 370
1,000
2,000
3,000
4,000
5,000
Launch Date (year)
UsefulInserted
Mass(kg)
Uranus, Delta-IV Heavy, 25 kW, NEXT 2+1
6.07.08.09.010.011.012.0
25 26 27 28 29 30 31 32 33 34 35 36 370
1,000
2,000
3,000
4,000
5,000
Launch Date (year)
UsefulInserted
Mass(kg)
Neptune, Delta-IV Heavy, 25 kW, NEXT 2+1
9.010.011.012.013.0
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CostingApproach• CostestimatesdevelopedbyJPL’sTeamXandtheAerospaceCorporation
• AssumptionsusedforcostingcomefromStudyGroundRules:• Allcostsin$FY15;Includeminimum30%reserves(A–D),15%(E-F)• AssumeClassB(perNPR8705.4),CategoryI(perNPR7120.5)mission• ExcludeLV• IncludecostofRPS includingNEPA/LA• Includeoperations(fulllifecyclemissioncost)• IncludeDSNasseparatelineitem• ReservesexcludedonRPSandLV
• Aerospaceindependentcostestimate(ICE)generallyhigherthanTeamXasaresultofmodelingdifferencesforflightsystemandoperations• Differenceswithintheerrorbarsoftheestimationtechniques
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ScienceDefinitionTeam
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Chairs: MarkHofstadter(JPL),AmySimon(Goddard)
ESAMembers:AdamMasters(Imp.College)DiegoTurrini (INAF-IAPS/UDA)
SushilAtreya(Univ.Mich.)DonaldBanfield (Cornell)JonathanFortney(UCSC)AlexanderHayes(Cornell)MatthewHedman (Univ.Idaho)GeorgeHospodarsky (U.Iowa)
KathleenMandt (SwRI)MarkShowalter(SETI Inst.)KristaSoderlund (Univ.Texas)ElizabethTurtle(APL)
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MissionDesignTeam
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• NASAInterface: CurtNiebur ESAInterface: LuigiColangeli
• StudyLead: JohnElliott JPLStudyManager: KimReh
MissionConceptDesignTerriAnderson(costing)DavidAtkinson(probes)Nitin Arora (trajectory)ChesterBorden(systemeng.)JimCutts (technology)YoungLee(RPS)Anastassios Petropoulos(trajectory)TomSpilker(science,systemeng.)DavidWoerner (RPS)
ScienceDefinitionTeamCo-Chairs:M.Hofstadter/A.SimonMembers:Seenextslide
OtherOrganizationsLangleyResearchCenter(TPS)AmesResearchCenter(TPS)PurdueUniversity(missiondesign)AerospaceCorp.(ICE)