On to the Ice Giants - Lunar and Planetary Institute...On to the Ice Giants Pre-Decadal study...

OntotheIceGiants

Pre-DecadalstudysummaryEuropeanGeophysicalUnion,24April2017

KimReh1,MarkHofstadter1,JohnElliott1,AmySimon21JetPropulsionLaboratory,CaliforniaInstituteofTechnology;2GoddardSpaceFlightCenter

©2017AllrightsReserved

Thecostinformationcontainedinthisdocumentisofabudgetaryandplanningnatureandisintendedforinformationalpurposes only.ItdoesnotconstituteacommitmentonthepartofJPLand/orCaltech.

April24,2017 Predecisional- Forplanninganddiscussionpurposesonly.URS265255,CL#17-1883 1

StudygoalandobjectivesGoal• Assessscienceprioritiesandaffordablemissionconcepts&optionsforexplorationoftheIceGiantplanets,UranusandNeptuneinpreparationforthenextDecadalSurvey.

Objectives• Evaluatealternativearchitecturestodeterminethemostcompellingsciencemission(s)thatcanbefeasiblyperformedwithin$2B($FY15)• Identifypotentialconceptsacrossaspectrumofpricepoints

• Identifymissionconceptsthatcanaddressscienceprioritiesbasedonwhathasbeenlearnedsincethe2013–2022DecadalSurvey

• Identifyenabling/enhancingtechnologies

• AssesscapabilitiesaffordedbySLS


Missionstudyteam–CharteredbyNASA;includedESA

NASAInterface: CurtNiebur ESAInterface: LuigiColangeli

StudyLead: JohnElliott JPLStudyManager: KimReh

JPLMissionConceptTeam

OtherOrganizationsLangleyResearchCenter(TPS)AmesResearchCenter(TPS)PurdueUniversity(missiondesign)AerospaceCorp.(ICE)

SushilAtreya (UMich.)DonaldBanfield (Cornell)JonathanFortnzey (UCSC)AlexanderHayzes (Cornell)MatthewHedman (UIdaho)GeorgeHospodarsky (UIowa)KathleenMandt (SwRI)MarkShowalter(SETIInst.)

KristaSoderlund (Univ.Texas)ElizabethTurtle(APL)

ESAmembersAdamMasters(Imp.College)DiegoTurrini (INAF-IAPS/UDA)

ScienceDefinitionTeam:Co-Chairs:M.Hofstadter,A.Simon


WhyareUranusandNeptuneimportant?• Theserelativelyunexploredsystemsarefundamentallydifferentfromthegasgiantsandtheterrestrialplanets• UranusandNeptuneare~65%waterbymass(incl.methane,ammoniaand

other“ices”).Terrestrialsaremostlyrock;Jupiter/Saturnare~85%H2 andHe

• Icegiantsappeartobeverycommoninourgalaxy

• Theychallengeourunderstandingofplanetaryformation,evolution,andphysics• Modelssuggesticegiantshaveanarrowtime

windowforformation.Ifthatiscorrect,whyaretheysocommoninotherplanetarysystems?

• WhyisUranusnotreleasingsignificantamountsofinternalheat?Doesitsoutputvaryseasonally?

• Whyaretheicegiantmagneticfieldssocomplex?Howdounusualgeometriesaffectinteractionswiththesolarwind?

Uranusin2012(left,Sromovskyetal.2015)and1986(right,Voyager)

IceGiantsarecriticaltounderstandinghowplanetarysystemsformandevolve


Scienceobjectivesassessment• AllelementsoftheIceGiantsystems(interior,atmosphere,rings,satellites,magnetosphere)haveimportantscienceobjectivesthatcannotbemetthroughEarth-basedobservations

• Determiningtheinteriorstructureandbulkcompositionoftheicegiantsisprioritizedasthehighest-payoffscience

• Scientificandtechnologicaladvances,andimprovedtrajectories,makethesemeasurementshigherprioritythanintheDecadalSurvey

• 12keyscienceobjectivesdrivemissionarchitectures(nextslide)

• Allobjectivesremainconsistentwith,traceableto,thedecadalsurvey


Illustrationofcompositionaldifferencesamongthegiantplanetsandtheirrelativesizes.Earthisshownforcomparison.JupiterandSaturnareprimarilyhydrogenandhelium,theterrestrialplanetsarealmostpurerock,whileUranusandNeptunearethoughttobelargelysupercriticalliquidwater.

12keyscienceobjectives

PlanetaryInterior/Atmosphere• Planetarydynamo• Atmosphericheat

balance• Tropospheric3-Dflow

Rings/Satellites• Internalstructureofsatellites• Inventoryofsmallmoons• Ringandsatellitesurface

composition• Ringstructures

andtemporalvariability

• Satelliteshapeandsurfacegeology

• Triton’satmosphere:origin,evolution,anddynamics

Magnetosphere• Solarwind-

magnetosphere-ionosphereinteractionsandplasmatransport

HighestPriority

• Interiorstructureoftheplanet• Bulkcompositionoftheplanet(includingisotopesandnoblegases)


ModelpayloadsSimilarforUranusandNeptune,andwhetherflybyororbiter.

Modelpayloadforprobe:• Massspectrometer• ASI(density,pressureandtemperatureprofile)• Hydrogenortho-parainstrument(storedenergyinweatherlayer)• Nephelometer

Modelpayloadfororbiter

50kgorbiterpayloadaddressesminimumacceptablescience• NAC,• DopplerImager,• Magnetometer.

90kgorbiterpayloadpartiallyaddresseseachscienceobjective.Addto50kgcase:• Vis/NIR imaging

spectrometer,• RadioandPlasmasuite,• ThermalIR,• Mid-IR(Uranus)orUV

(Neptune)spectrometer.

150kgorbiterpayloadcomprehensivelyaddressesallscienceobjectives.Addto90kgcase:• WAC,• USO,• EnergeticNeutralAtoms,• Dustdetector,• Langmuirprobe,• Microwavesounder/Massspec.


Sciencevaluevsarchitectures• Widerangeofarchitecturesassessed;ranked

scientificallyandcosted

• Orbiterwithprobeisscientificallycompellingandmeetsstudycosttarget

• Addingseconds/ctotheothericegiantsignificantlyenhancessciencereturn

• Therelativesciencescoreofamissionisalmostlinearwithcost(constantscienceperdollar),highlightingthatwearenotinaregimeofdiminishingreturns.

• Increasinginvestmentinmissionelementsproducesacorrespondinglylargerincreaseinsciencereturn.


!1 2 3 4

Aerospacecostbasis- 70%confidencelevelreserves

Subsetofarchitectureswith(50kg)payload.Centerofeachlabelindicatesrelativecost.

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


Missiondesigntakeaways• Optimallaunch opportunitiestoUranus&Neptunein2029-2032useJupitergravityassist

• MissionstoUranusviaSaturnarepossiblethroughmid-2028;JGAtakesoverinthe2030s• Nosuchmissionoptions(viaSaturn)existforNeptune• Launchesarepossibleanyyear

• Chemicaltrajectoriesdeliver1500kgorbitertoUranusin<12yearsusingAtlasV• Delta-IVHeavycanreduceinterplanetaryflighttimeby1.5years

• NochemicaltrajectoriesexistfordeliveringaflagshipclassorbitertoNeptunein<13yearsusingAtlasVorDelta-IVHeavylaunchvehicles• SLSorlongerflighttimeswouldbeneeded.

• SEPEnablesaflagshiporbitertoNeptunein12-13years• Implementedasseparablestagetominimizepropellant

requiredforinsertion

• Orbitinsertion∆VatbothUranusandNeptuneishigh• Neptune:2.3-3.5km/s• Uranus:1.5-2.5km/s

13-yrEVEEJUexample


PotentialbenefitsofSLS

Allsingle-planetmissionconceptsstudiedareachievablewithexistingELVsSLScanprovideenhancingbenefits:• Increasesdeliverablemassandlowersflighttimeby3to4years

• EnableschemicalNeptunemissionin11.5years

• Enablestwo-spacecraftmissionswithasinglelaunch

• IncreaseslaunchopportunitiesWhencombinedwithaerocapturecapability,enablesverylowflighttimesforbothUranus(<5years)andNeptune(<7years)


Commonbuildingblocksforarchitectureassessment

NeptuneOrbiterwithProbe,SEP,and50kgpayload

UranusFlybywithProbeand

50kgpayload

UranusOrbiterwithProbeand

50kgpayload

UranusOrbiterwith150kgpayload

Launchmass:7364kg

Launchmass:1525kg

Launchmass:4345kg

Launchmass:4718kg


Conceptswerechosentoconstrainthescience/costparameterspace

CommonprobeconceptforUranusandNeptune

Instruments• MassSpectrometer• AtmosphericStructure

Instrument(ASI)• Nephelometer• Ortho-paraHydrogen

Instrument

320kgincluding43%margin


HEEETTPS

Ventedprobe

H2Ortho-paraInstrument

Concepttechnicalsummary

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

Payload 3instruments†+atmosphericprobe

3instruments†+atmosphericprobe

3instruments†+atmosphericprobe 15instruments‡

PayloadMassMEV(kg) 45 45 45 170LaunchMass(kg) 7365 1524 4345 4717LaunchYear 2030 2030 2031 2031FlightTime(yr) 13 10 12 12TimeinOrbit(yr) 2 Flyby 3 3TotalMissionLength(yr) 15 10 15 15RPS use/EOMPower 4eMMRTGs/376W 4eMMRTGs/425W 4eMMRTGs/376W 5eMMRTGs/470WLV DeltaIVH+25kWSEP AtlasV541 AtlasV551 AtlasV551PropSystem DualMode/NEXTEP Monopropellant DualMode DualMode

†includesNarrowAngleCamera,DopplerImager,Magnetometer‡includesNarrowAngleCamera,DopplerImager,Magnetometer,Vis-NIRMapping Spec.,Mid-IRSpec.,UVImagingSpec.,PlasmaSuite,ThermalIR,EnergeticNeutralAtoms,DustDetector,LangmuirProbe,MicrowaveSounder,WideAngleCamera



Costingapproach• CostestimatesdevelopedbyJPL’sTeamXandtheAerospaceCorporation

• GroundRulesusedforcosting:• $FY15;minimum30%reserves(A–D),15%(E-F)• RiskClassB(perNPR8705.4),CategoryI(perNPR7120.5)• ExcludeLV• IncludecostofRPS includingNEPA/LA• Includeoperations(fulllifecyclemissioncost)• IncludeDSNasseparatelineitem• ReservesexcludedonRPSandLV

• AerospaceindependentcostestimatehigherthanTeamXasaresultofmodelingdifferencesforflightsystemandoperations• Differenceswithintheerrorbarsoftheestimationtechniques



Conceptcostsummary

CaseDescription

NeptuneOrbiterwithprobeand<50kgsciencepayload.IncludesSEPstage forinner

solarsystemthrusting

UranusFlybyspacecraftwithprobeand<50kgscience

payload

UranusOrbiterwithprobeand<50kgsciencepayload.

Chemicalonlymission.

Uranus Orbiterwithoutaprobe,and150kgscience

payload.Chemicalonlymission.

TeamXCostEstimates($k,FY15)

TotalMissionCost* 1971 1493 1700 1985PhaseA-DCost(incl.Reserves) 1637 1293 1406 1418

AerospaceICE($k,FY15)TotalMissionCost* 2280 1643 1993 2321

PhaseA-DCost(incl.Reserves) 1880 1396 1559 1709*IncludescostofeMMRTGs,NEPA/LA,andstandardminimaloperations,LVcostnotincluded.Thecostinformationcontainedinthisdocumentisofabudgetaryandplanningnatureandisintendedforinformationalpurposes only.ItdoesnotconstituteacommitmentonthepartofJPLand/orCaltech.

• Neptunemissionscost~$300MmorethanUranusforcomparablesciencereturn(SEP)

• TheUranusorbiterwithprobemissionisestimatedtobeintherangeof$1.7to$2.6Bdependingontheorbiterpayload(50-150kgrange)andreserveposture



Technologyconsiderations• InSpaceTransportation

• Aerocapture• LOX-LH2chemicalpropulsion• RadioisotopeElectricPropulsion(REP)

• OpticalCommunications(Beyond3AU)• Smallsatellitesinmassrange100to400kg,CubeSats• AdvancedRadioisotopePower

• eMMRTG (potential)• SegmentedModularRadioisotopeThermoelectricGenerator(SMRTG)concepts• HighPowerStirling RadioisotopeGenerator(HPSRG)concepts

• HEEETthermalprotectionsystem

• IceGiantsconceptscanbeimplementedwitheMMRTG andHEEETtechnologycurrentlyindevelopment.


Primarystudyfindings

• AUranusorbiterwithprobe,launchingnear2030,remainsthehighestprioritymissionconcept

• Two-planet,two-spacecraftmissionoptionsarehighlyvaluablescientificallyatproportionallyhighercost,yetlessthanthecostoftwoindependentmissions

• Internationalcollaborationisanopportunitytomaximizesciencereturnwhileminimizingcosttoeachpartner;makesbestuseofonce-in-lifetimeopportunity

• Afollow-onmissionstudyshouldbeperformedthatusesrefinedprogrammaticground-rulestobettertargetthemissionlikelytofly


OntotheIceGiantsin2030?• Suchamissionwouldengageallplanetarysciencedisciplinesandheliophysics andexoplanetscientists

• TimingprovidesopportunitytomaptheNorthernHemispheresoftheUraniansatellites,andsampleuniquesolarwindgeometries

• Nonewtechnologyisrequired;lowdevelopmentrisk

• Architecturerichwithaffordableinternationalcostshareoptions

• WouldcompleteDecadalSurveyrecommendedFlagshipmissions

Ó Woods Whole Oceanographic Institute & Kevin Hand


On to the Ice Giants - Lunar and Planetary Institute...On to the Ice Giants Pre-Decadal study...

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