NASA/TP–2015–216648/REV1 Small Spacecraft Technology State of the Art MissionDesignDivision AmesResearchCenter,MoffettField,California December2015 NASA STI Program ...in Profile Sinceitsfounding,NASAhasbeendedicated CONFERENCEPUBLICATION. totheadvancementofaeronauticsandspace • Collectedpapersfromscientificand science.TheNASAscientificandtechnical technicalconferences,symposia,seminars, information(STI)programplaysakeypart orothermeetingssponsoredor inhelpingNASAmaintainthisimportant co-sponsoredbyNASA. role. SPECIALPUBLICATION.Scientific, • TheNASASTIProgramoperatesunderthe technical,orhistoricalinformationfrom auspicesoftheAgencyChiefInformation NASAprograms,projects,andmissions, Officer.Itcollects,organizes,providesfor oftenconcernedwithsubjectshaving archiving,anddisseminatesNASA’sSTI. substantialpublicinterest. 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Availablefrom: NASACenterforAeroSpaceInformation NationalTechnicalInformationService 7115StandardDrive 5301ShawneeRoad Hanover,MD21076-1320 Alexandria,VA22312 443-757-5802 703-605-6000 Thisreportisalsoavailableinelectronicformat Abstract This report provides an overview of the current state of the art of small spacecraft technology.It was firstcommissioned by NASA’sSmall SpaceraftTechnologyProgram(SSTP)in mid-2013 in response totherapidgrowthininterestinusingsmallspacecraftformanytypesofmissionsinEarthorbit andbeyond,andrevisedinmid-2015.Forthesakeofthisassessment,smallspacecraftaredefined tobespacecraftwithamasslessthan180kg. Thisreportprovidesasummaryofthestateof theartforeachofthefollowingsmallspacecrafttechnologydomains:CompleteSpacecraft,Power, Propulsion, Guidance Navigation and Control, Structures, Materials and Mechanisms, Thermal Control,CommandandDataHandling,Communications,Integration,LaunchandDeployment, Ground Data Systems and Operations, and Passive Deorbit Devices. Due to the high market penetrationofcubesats,particularemphasisisplacedonthestateoftheartofcubesat-related technology. 1 Disclaimer Thedocumentlistsordescribesmanyspecificproductsandtechnologiesasexamplesandreferences buttheirinclusiondoesnotimplyanyendorsementbyNASA.Failuretoincludeanyspecificprod- uctsortechnologiesthatmightbeconsideredrelevantunderaparticulartopicwasunintentional. Acknowledgements Thisreporthasbeenbasedlargelyondesktopresearchandpublisheddocumentsonsmallspace- crafttechnology,industryconsultationandparticipationatconferences. Helpfulsuggestionsand contributionswerealsoreceivedfromnumerouspeopleatNASAAmesResearchCenter,andinpar- ticulartheauthorswishtoacknowledgethereviewersJamesBell,JoshBenton,MattD’Ortenzio, JoshForgione,VanessaKuroda,DawnMcIntosh,MarcMurbach,MattNehrenz,HugoSanchez, MattSorgenfrei,SarahThompson,EddieUribeandBruceYost. FromNASAGlennResearchCentertheauthorswouldliketothankthereviewersMattDeans, FredElliot, JoshFreeh, DavidJacobson, WilliamMarshall, FelixA.Miranda, TimSmithand BrandonWhite. Finally,theauthorswouldliketothankallofthecompaines,universitiesandorganizationswho providedinformationforthisreport. 2 NASA Ames Research Center, Mission Design Division September, 2015 Division Chief: ChadFrost Project Manager: ElwoodAgasid Editor: RoganShimmin Contributing Authors: ElwoodAgasid,RolandBurton,RobertoCarlino,GregoryDefouw,Andres DonoPerez,ArifGöktuğKaracalıoğlu,BenjaminKlamm,Abraham Rademacher,JamesSchalkwyk,RoganShimmin,JuliaTilles,SashaWeston 3 Contents 1 Introduction 14 1.1 Objective .......................................... 14 1.2 Scope ............................................ 14 1.3 Assessment ......................................... 14 1.4 Overview .......................................... 15 2 IntegratedSpacecraftPlatforms 18 2.1 Introduction ......................................... 18 2.2 State of the Art ....................................... 18 2.3 On the Horizon ....................................... 22 2.4 Conclusion .......................................... 23 3 Power 25 3.1 Introduction ......................................... 25 3.2 State of the art ....................................... 25 3.2.1 Power Generation.................................. 25 3.2.2 Power Storage.................................... 28 3.2.3 Power Management and Distribution ....................... 32 3.3 On the horizon ....................................... 35 3.3.1 Power Generation.................................. 35 3.4 Conclusion .......................................... 38 4 Propulsion 40 4.1 Introduction ......................................... 40 4.2 State of the art ....................................... 41 4.2.1 Chemical Propulsion Systems ........................... 41 4.2.2 Electric Propulsion Systems ............................ 50 4.2.3 Propellant-less Systems .............................. 57 4.3 On the Horizon ....................................... 57 4.4 Conclusion .......................................... 60 5 Guidance,NavigationandControl 63 5.1 Introduction ......................................... 63 5.2 State of the art ....................................... 63 5.2.1 Integrated Units .................................. 63 5.2.2 Reaction Wheels .................................. 64 5.2.3 Magnetorquers ................................... 66 5.2.4 Thrusters ...................................... 66 5.2.5 Star Trackers .................................... 66 5.2.6 Magnetometers ................................... 66 5.2.7 Sun Sensors ..................................... 68 5.2.8 Earth Sensors .................................... 69 5.2.9 Gyros ........................................ 69 5.2.10 GPS ......................................... 71 5.2.11 Deep Space Navigation............................... 71 5.3 On the Horizon ....................................... 72 5.4 Conclusion .......................................... 72 4 6 Structures,MaterialsandMechanisms 74 6.1 Introduction ......................................... 74 6.2 State of the art ....................................... 74 6.2.1 Primary Structure ................................. 75 6.2.2 Mechanisms ..................................... 76 6.3 On the Horizon ....................................... 78 6.4 Radiation Effects and Mitigation Strategies . 80 6.4.1 Shielding from the Space Environment ...................... 80 6.4.2 Inherent Mass Shielding .............................. 81 6.4.3 Ad Hoc Shielding .................................. 82 6.5 Conclusion .......................................... 82 7 ThermalControlSystem 84 7.1 Introduction ......................................... 84 7.2 State of the Art ....................................... 84 7.2.1 Passive Systems................................... 84 7.2.2 Active Systems ................................... 88 7.3 On the Horizon ....................................... 93 7.4 Conclusion .......................................... 95 8 CommandandDataHandling 98 8.1 Introduction ......................................... 98 8.2 State of the art ....................................... 98 8.2.1 Form Factor ..................................... 98 8.2.2 On-Board Computing ............................... 98 8.2.3 Memory and Electronic Components .......................100 8.2.4 Bus Electrical Interfaces and I/O .........................103 8.2.5 Electronic Power Supplies .............................104 8.3 On the Horizon .......................................104 8.4 Radiation mitigation and tolerance schemes