laser communica.ons downlink and crosslink designs for...
TRANSCRIPT
LaserCommunica.onsDownlinkandCrosslinkDesignsforCubesats
EmilyClementsCalPolyCubeSatWorkshop2016
PI:Prof.KerriCahoy
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• TheNeedforCubeSatLasercom- Mo6va6on- Keydesigntrades
• ApproachandEnablingTechnologies• OngoingMITPrograms:- NanosatelliteOp6calDownlinkExperiment(NODE)- FreespaceLasercomAndRadia6onExperiment(FLARE)- KitCube
• TheFutureofCubeSatLasercom
Outline
TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
TheNeedforCubeSatLasercom• Transi6oningtomoreadvancedpayloadsrequireshigherdatarates
thanUHFwithtapespringantennacanprovide[4]• Transmitpowerandcost/accessibilityofhigh-gaingroundsta6onsare
usuallythelimi6ngfactorsinCubeSatRFdatarate[5]
• Lasercommunica6onismorepower-efficientthanRF:– ChannelcapacityCscaleswithwavelengthλ:
à LasercomisanaIrac.vesolu.onforfutureprograms
• Ongoingcompactlasercomwork:AerospaceOCSD[15],Facebook[16],DLR[17],BridgeSat/Surrey,RUAG,MITprograms,&others– Relatedtechnology:CHOMPTT[20]
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COpt.
CRF
∝λRFλopt.
⎛
⎝⎜⎜
⎞
⎠⎟⎟
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TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
CommforAdvancedLEOCubeSats
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• Figureassumespayloadsarerunningcon6nuously&downlinkisnotlimitedbynumberordura6onofpasses
• High-power,high-datapayloadsdriveneedforCubeSatLasercom
Orbitalpowerusage[Wh]
30
20
100
~13Wh/orbitgeneratedby3UCubeSatwithdeployablesolarpanels[11]
0.2MB/orbitMagnetometer[6]
200MB/orbit3Mpcamera[8]
28,000MB/orbitLow-resolu6onvideo[4,10]
7500MB/orbitHyperspectral[9]
PayloadPower3MbpsUHFConsumedPower[12]5MbpsSBandConsumedPower[13]100MbpsXBandConsumedPower[14]50MbpsLasercomConsumedPower(NODEwith1mgroundsta6on)
~26Wh/orbitgeneratedby6UCubeSatwithdeployablesolarpanels
Clements2016
TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
LasercomPoin6ngChallenges
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NODE
FLAREKitCube
• Keychallenge:poin.ngcontrol- Lasercombeamwidthstestlimits
ofCubeSataetudecontrolwithEarthHorizonSensors(EHS)&SunSensors(SS)
• Wewilldiscusssolu6onsMIT
CubeSatlasercomprograms:- NODE:LEOdownlink[2]- FLARE:CrosslinksinLEO- KitCube:Downlinkfromlunar
orbit[18]
LasercomPower&BeamwidthTrade
Startrackerreq’d
EHS+SS
Clements2016
Beamwidth(milliradians)
Transm
itPo
wer(W
)
TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
COTSforCubeSatLasercom
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Spaceterminalpoin.ngcontrolenabledbyCOTSFastSteeringMirror(FSM)Credit:KathleenRiesing
Seed$Laser$+$ER$Filter$FPGA$ EDFA$
FPGA$Electrical$Output$ EDFA$Filtered$Op8cal$Input$ EDFA$Op8cal$Output$PPM<16$
5$ns$pulse$$
+23$dBm$
ER>33dB$High$fidelity$waveform$ASE<0.2$dB$
<7$dBm$
TransmiIerelectronicsleveragestelecomtechnologyCredit:RyanKingsbury[2]
MITGroundsta.onusesAmateurTelescopeandlaptop
Credit:HyosangYoon
SelectedCOTStecharchitecturewithamplifica.onusingEDFAtoenablelowcost(<$20kinpartscost)systemscalableto100Mbps
TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
Uncertainty-basedLinkAnalysisDevelopingnewlinkanalysisapproachtohandlesystemuncertain.es:• COTSpartsnotyetqualifiedforspaceenvironment• Tradi6onal,worst-caselinkanalysisistooconserva6veforrisk-tolerantCubeSats• Probabilis6cmodelingapproachtolasercomlinkbudgetshelpstoassessrisks
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Clements2016
TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
Uncertainty-basedLinkAnalysis
à Howtoaddressuncertain.es:Useglobalsensi6vityanalysistoiden6fyuncertain6eswithhighestimpactonLinkMargin• Globalsensi6vityanalysishelpstovisualizecontributorstoperformanceuncertainty
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Clements2016
SobolSensi6vi6es
TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
NODEOverview
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Receiver- OCTLandAmateurtelescope- Detector:COTSavalanche
photodiode- Poin6ngandtracking:COTS
infraredcamera+startracker
TransmiIer- Electronics:Commercialtelecomlaser
components,PPMmodula6on- Mechanical:3Dprintedstructure- Poin6ngstrategy:buspoin6ng(coarsepoin6ng),
Faststeeringmirror(finepoin6ng)- Componentsintwosubmodules
TransmikerEDFAsubmodule
Transmikerop6cssubmodule
120mm
• NanosatelliteOp6calDownlinkExperiment• 10-100MbpsdownlinkfromLEOCubeSatw/1550nm,2.26mradbeam• <10Wconsumedpowerfor0.2Wtransmitpower• LeveragesCOTSpartsfortransmikerandreceiver
Credit:HyosangYoonCADCredit:DerekBarnes
TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
NODEI&TProgressUpdate
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FSM&TransmiIerPrototyping
MechanicalPrototyping GroundSta.onPrototyping
Func.onalTes.ng
PhotoCredit:ClementsGSlead:HyosangYoon
Photocredit:ClementsPrototyping:Aniceto,Barnes,Clark,Haughwout
Photocredits:ClementsPrototyping:Clark,Haughwout
Photocredit:ClementsPrototyping:Ziegler,Lee
TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
FreespaceLasercomandRadia6onExperiment• Intersatellitelasercommunica6onswithCubeSats• Twosatellites,compacthalf-duplextransceiversystem• MIT’sentryintotheAFRLUNP-9compe66on• Pre-PDR
FLAREMissionOverview
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CADCredit:MaximKhatsenko
Lasercomtransmitaperture(2.26mradbeam) 8.5cmlasercom
receiveaperture
ADCSprovides3axisaetudecontrol
Powermanagement&bakeries
Sparrow[19]module(SecondaryPayload)
Sparrowwindow(SecondaryPayload)
4thrustersmaintainsatellitecrosslink
distance
FuelTank
EDFAoutputs1550nm1.2Wlasersignal
BusFPGAgeneratessignalforlasercomseedlaser&interpretsreceivedsignals
TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
ProgramObjec.ves• MIT’sentryintotheNASACubeQuestChallenge• Designandbuilda6UCubeSatthatwinsoneofthe3remainingspotsonSLSEM-1.• Achievelunarorbit($1.5M)• GoalofwinningtheBestBurstDataRatecompe66onwithalasercommunica6ons
downlinktransmiker.• Alsocompeteforlargestaggregatedatavolume,andlongevity.
KitCubeMissionOverview
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Lasercompayload:• 1550nm1.2Wtransmiker• 0.1mradbeam• BeaconreceiverPoin6ngsolu6ons:
• Reac6onwheels• Twostartrackers
CADCredit:MaximKhatsenko
TheneedforCL Approach/EnablingTech OngoingPrograms FutureofCL
TheFutureofCubeSatLasercom
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LEOdownlinkMITexample:NODE>50Mbpswith0.2Wtransmiker&1mgroundsta6onOtherexamples:AerospaceOCSD,CHOMPTT
LEOdownlink½Upayload&groundsta6onnetworkwouldenablehigherdutycyclesofadvancedCubeSatpayloads
LEOcrosslinkMITexample:FLARE>10Mbpswith1.2Wtransmiker
LEOcrosslinkLow-powercrosslinksreducelatencyofdownlinkingpayloaddata
UpcomingTechDemoMissions(MITexamples;manyothersexist)
FutureArchitectures
LunardownlinkMITexample:KitCube>1Mbpswith1.2Wtransmiker
DeepspaceCubeSatscouldbeusedasprobesoninterplanetarymissions(ex.Starshot),withthecommunica6onabilitytorelayfindingsbacktoEarth
AcknowledgementsStudents(pastandpresent)GraduateStudentsInigodelPor6lloBarriosKateCantuAshleyCarltonJimClarkEmilyClementsAngieCrewsKarlGantnerChris6anHaughwoutAyeshaHeinKitKennedyMaximKhatsenkoRyanKingsburyCharlokeLoweyMyronLeeZachLeeWestonMarlowKatRiesingArmenSamurkashianDivyaShankarHyosangYoonCalebZiegler
UndergraduateStudentsRaichelleAnicetoDerekBarnesScarlekKollerBjarniKris6nssonRachelMorganMayaNasrJohannesNorheimElishevaShuterRachelWeinbergHighSchoolStudentsBradenOh+ProjectSeleneteamAdvisorsProfessorsKerriCahoy
MentorsJamieBurnsideDaveCaplan(MITLL)BillFarr(NASAJPL)ZachHartwig(MITPost-doc)JeffMendenhall(MITLL)JonathanTwichell(MITLL)
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References1. Swartwout,Michael."Thefirstonehundredcubesats:Asta6s6callook."JournalofSmallSatellites2.2(2013):213-233.2. Kingsbury,R.W.,D.O.Caplan,andK.L.Cahoy."Compactop6caltransmikersforCubeSatfree-spaceop6calcommunica6ons."SPIE
LASE.Interna6onalSocietyforOp6csandPhotonics,2015.3. hkp://www.klofas.com/comm-table/table.pdf4. Selva,Daniel,andDavidKrejci."Asurveyandassessmentofthecapabili6esofCubesatsforEarthobserva6on."ActaAstronau6ca74
(2012):50-68.5. Bouwmeester,Jasper,andJ.Guo."Surveyofworldwidepico-andnanosatellitemissions,distribu6onsandsubsystemtechnology."
ActaAstronau6ca67.7(2010):854-862.6. Long,Makhew,etal."Acubesatderiveddesignforauniqueacademicresearchmissioninearthquakesignaturedetec6on."Proc.
AIAASmallSatelliteConference.2002.7. AnneMarinan,PersonalCommunica6on8. hkp://www.cubesatshop.com/index.php?
page=shop.product_details&flypage=flypage.tpl&product_id=63&category_id=16&op6on=com_virtuemart&Itemid=809. hkp://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150023589.pdf10. hkp://cdn2.hubspot.net/hubfs/145999/docs/VNIR.pdf?t=145986198180711. Blackwell,William,etal."MicroMAS:AFirstStepTowardsaNanosatelliteConstella6onforGlobalStormObserva6on."(2013).12. Marinan,AnneDorothy.FromCubeSatstoconstella6ons:systemsdesignandperformanceanalysis.Diss.MassachuseksIns6tuteof
Technology,2013.13. hkp://www.tethers.com/SpecSheets/Brochure_SWIFT_SLX.pdf14. hkp://www.tethers.com/SpecSheets/Brochure_SWIFT_XTS_SFN.pdf15. Welle,RichardP."CUBESAT-SCALELASERCOMMUNICATIONS."(2015).16. hkp://www.wired.com/2016/01/facebook-zuckerberg-internet-org/17. Schmidt,Christopher,etal."OSIRISpayloadforDLR’sBiROSsatellite."Proc.ofInterna6onalConferenceonSpaceOp6calSystems
andApplica6ons(ICSOS),Kobe,Japan.2014.18. hkps://crowdfund.mit.edu/project/150119. Chris6anHaughwout,ZachHartwig,AshleyCarlton,andKerriCahoy.“MiniaturePar6cleDiscrimina6ngRadia6onSensors:
TechnologyDevelopmentandDemonstra6onona1UCubeSat”.PosteratCubesatCommunitySymposium,September2015,IrvineCA
20. Barnwell,Nathan,etal."CubeSatHandlingofMul6systemPrecisionTimeTransfer."(2015).
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BackupSlides
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PPM Diagrams
Credit:RyanKingsbury
Credit:LaserCommunicaFonTransmiHerandReceiverDesignbyDaveCaplan
Abstract"LaserCommunica6onsDownlinkandCrosslinkDesignsforCubeSats”Op6calcommunica6on,orlasercom,canprovidemuchhigherlinkratesthananRFsystemwithcomparableenergyconsump6on.Thisisbecauseop6calsignalscanbedirectedmoreeffec6velytowardsthegroundsta6on.Themainengineeringcostsassociatedwiththesesystemsarethestringentpoin6ngrequirementsthatareleviedonthelasertransmiker.RecentadvancesinCubeSataetudedetermina6onandcontrolsystems(ADCS)areaddressingtheseneeds,andtherehavebeenseveralmissionsthathavedemonstratedthree-axisstabiliza6on–akeyenablerforlasercom.Wediscussdevelopmentsinlasercommunica6onscapabili6esfordownlinkandcrosslinkon3Uand6Unanosatellitepla�ormsandgroundsta6onsbasedlargelyoncommerciallyavailablecomponents.Wepresentpredictedandprototypedcapabili6esofspacecra�transmikersandreceiversforapower-constrained1550nmdirect-detec6onsystemwithaverageoutputpowerrangingfrom200mWto1.2Wforthreecasestudies:low-Earthorbitdownlink,low-Earthorbitcrosslink,anddeepspacedownlink.Wedescribeexpectedperformanceforarepresenta6veorbitalconfigura6ons,includingconsidera6onofpropulsionandpoin6ngcapability,aswellasgroundsta6ongeometriesforthesecasestudies.Passiveandac6vebeaconapproachesarealsoconsidered.ThecasestudiescaptureongoingworkatMITontheNanosatelliteOp6calDownlinkExperiment(NODE),theMITKitCubeentryintheNASACubeQuestLunarDerbyChallenge,andtheFree-spaceLasercomandRadia6onExperiment(FLARE)intheUniversityNanosatelliteProgram9.Lasercomhasthepoten6altounlocklargeamountsofbandwidthatop6calwavelengthsevenforresource-constrainedCubeSatpla�orms.Thehighlydirectednatureoftheop6callinksmakethemextremelydifficulttointerceptandjamresistant.Thesesamelinkparametersalsosupportextensivespa6alreuseofcarrierfrequencies.Weuseonboardmemorystoragetoaddressweather/availabilityconcernsforusingop6caltransceiversforgrounduplinkanddownlink.Manymissionsdonothave“real-6me”downlinklatencyrequirements,sodatacanbestoredonboardun6lagroundsta6onisavailable.Applica6onswithmorestringentlatencyrequirementscanfieldaddi6onalgeographicallydiversegroundsta6ons,par6cularlyifthegroundsta6onsarecompactandlow-cost.
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