Micro Newton Thruster Development: Direct Thrust Measurements and Thruster Downscaling

181 Pages·2018·9.734 MB·English

by  Franz Georg Hey (auth.)

Franz Georg Hey
Micro Newton
Thruster
Development
Direct Thrust Measurements
and Thruster Downscaling
Micro Newton Thruster Development
Franz Georg Hey
Micro Newton Thruster
Development
Direct Thrust Measurements
and Thruster Downscaling
Franz Georg Hey
Friedrichshafen, Germany
Dissertation, Dresden University of Technology, 2017 with the title “Development and
Test of a Micro-Newton Thruster Test Facility and Micro-Newton HEMPTs”
ISBN 978-3-658-21208-7 ISBN 978-3-658-21209-4 (eBook)
https://doi.org/10.1007/978-3-658-21209-4
Library of Congress Control Number: 2018935282
Springer Vieweg
© Springer Fachmedien Wiesbaden GmbH 2018
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Acknowledgements
ThisworkhasbeenperformedintheLaboratoryforEnablingTechnologiesofAirbus
inFriedrichshafeninclosecollaborationwiththeDresdenUniversityofTechnology
andtheUniversityofBremen/DLRBremen.
Therefore,IwanttothankmycolleaguesatAirbus,inparticularUlrichJohann,
DennisWeise,NoahSaks,KarlheinzEckert,EwanFitzsimons,HansReinerSchulte,
AndreasKeller,HaraldKögel,OliverMandel,MaxVaupelandMarjetkaKastner.
FromtheDresdenUniversityofTechnology,IwanttothankMartinTajmar.
IwouldliketoacknowledgethesupportofMartinGohlke,ThiloSchuldt,Tim
BrandtandClausBraxmaierinBremen.
TheRadioFrequencyIonThrustertestedhasbeenprovidedbytheArianeGroup,
thanksgotoChristianAltmannandHansLeiter,MarcelBerger.
MyspecialacknowledgementgoestoGünterKornfeld,whoseideaitwastousea
cuspstructuredmagneticfieldasathruster.
Lastly,IwouldliketothankKarolinandmyfamilyfortheirsupport.
FranzGeorgHey
Contents
1 Introduction 1
1.1 MissionsforMicro-NewtonThrusterApplications . . . . . . . . . 1
1.2 MicroPropulsionThrustersOverview . . . . . . . . . . . . . . . 7
1.3 MicroNewtonTestFacilitiesinEurope . . . . . . . . . . . . . . . 9
1.4 AirbusDevelopmentApproach . . . . . . . . . . . . . . . . . . . 11
2 ElectricPropulsionFundamentals 15
2.1 BasicEquations. . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.2 BasicPlasmaPhysics . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.3 ElectricPropulsionThrusterTypes . . . . . . . . . . . . . . . . . 22
2.3.1 FieldEmissionElectricPropulsion . . . . . . . . . . . . . 23
2.3.2 RadioFrequencyIonThruster . . . . . . . . . . . . . . . 24
2.3.3 HighEfficiencyMultistagePlasmaThruster . . . . . . . . 26
2.4 ThrusterCharacterisation . . . . . . . . . . . . . . . . . . . . . . 29
2.4.1 DirectThrustMeasurement . . . . . . . . . . . . . . . . . 30
2.4.2 IndirectThrustMeasurement . . . . . . . . . . . . . . . . 36
3 Micro-NewtonThrusterTestFacility 43
3.1 VacuumFacility . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.2 PlasmaDiagnosticSetup . . . . . . . . . . . . . . . . . . . . . . . 52
3.2.1 FaradayCup . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.2.2 RetardingPotentialAnalyser . . . . . . . . . . . . . . . . 57
3.2.3 PlasmaDiagnosticCalibration . . . . . . . . . . . . . . . 60
3.3 AirbusMicro-NewtonThrustBalance . . . . . . . . . . . . . . . 61
3.3.1 MechanicalBalanceSetup. . . . . . . . . . . . . . . . . . 64
3.3.2 OpticalBalanceReadout . . . . . . . . . . . . . . . . . . 70
3.3.3 ThrustBalanceControllingandDataAcquisition . . . . . 75
3.3.4 BalanceCalibrationandUncertaintyAnalysis . . . . . . . 79
3.3.5 ThrustBalanceCharacterisation,TestingandAnalysis . . 85
3.4 TestFacilityRealThrusterMeasurementResultsandAnalysis . . . 92
4 MicroHighEfficiencyMultistagePlasmaThrusterDevelopment 105
4.1 NextGenerationμHEMPTDevelopmentApproach . . . . . . . . 108
VIII Contents
4.2 TheNextGenerationμHEMPT . . . . . . . . . . . . . . . . . . . 114
4.2.1 FullSizeNG-μHighEfficiencyMultistagePlasmaThruster
(HEMPT) . . . . . . . . . . . . . . . . . . . . . . . . . . 117
4.2.2 MiniaturisedNG-μHEMPT. . . . . . . . . . . . . . . . . 128
4.3 NG-μHEMPTDevelopmentSummary . . . . . . . . . . . . . . . 141
5 ConclusionandOutlook 147
Bibliography 157
Appendix 167
List of Figures
1.1 LaserInterferometerSpaceAntenna(LISA)constellation . . . . . 2
1.2 SketchoftheLISAOrbit . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Summaryofthethrustnoiserequirements . . . . . . . . . . . . . 5
1.4 ImpressionoftheDarwinconfiguration . . . . . . . . . . . . . . 6
2.1 ExBdriftillustration . . . . . . . . . . . . . . . . . . . . . . . . 20
2.2 Visualisationofamagneticbottle . . . . . . . . . . . . . . . . . . 21
2.3 FEEPprinciple . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.4 Simplified view of a two gridded Radio Frequency Ion Thruster
(RIT)system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2.5 SchematicoftheHEMPTconcept . . . . . . . . . . . . . . . . . . 26
2.6 HEMPTplasmapotential . . . . . . . . . . . . . . . . . . . . . . 28
2.7 Pendulumbalancestepresponse . . . . . . . . . . . . . . . . . . 32
2.8 Bodeplotofanarbitrarypendulumbalance . . . . . . . . . . . . 33
2.9 MechanicalBalanceConfiguration . . . . . . . . . . . . . . . . . 35
2.10 Faradaycupschematic . . . . . . . . . . . . . . . . . . . . . . . . 37
2.11 ExampleofFaradaycupmeasurement . . . . . . . . . . . . . . . 38
2.12 ExampleofaRPAmeasurement . . . . . . . . . . . . . . . . . . . 39
3.1 Insideviewofthemicro-Newtonthrustertestfacility . . . . . . . 43
3.2 Blockdiagramofelectricthrustertestfacilityconnections . . . . . 44
3.3 Illustrationofthevacuumfacility . . . . . . . . . . . . . . . . . . 47
3.4 Flowchartofthevacuumsetup . . . . . . . . . . . . . . . . . . . 49
3.5 Measurednoisespectraoftwodifferentcryocoolers . . . . . . . . 50
3.6 Crosssectionalsnapshotofthecustomcryopumpsystem . . . . 51
3.7 Flowchartoftheplasmadiagnosticsetup. . . . . . . . . . . . . . 54
3.8 IllustrationofthedevelopedFaradaycupunit . . . . . . . . . . . 55
3.9 Drawingoftheplasmadiagnosticassembly. . . . . . . . . . . . . 56
3.10 PictureofthedevelopedRetardingPotentialAnalyser(RPA) . . . 57
3.11 SketchoftheRPA . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.12 ResultoftheFaradaycupcalibration . . . . . . . . . . . . . . . . 61
3.13 Sketchofthependulumbalanceprinciple. . . . . . . . . . . . . . 63
3.14 Illustrationofthethrustbalancesetup . . . . . . . . . . . . . . . 65
X ListofFigures
3.15 PendulumBearingillustration . . . . . . . . . . . . . . . . . . . . 67
3.16 Illustrationofasinglependulumsubassembly . . . . . . . . . . . 68
3.17 Heterodynefrequencygenerationsetup. . . . . . . . . . . . . . . 70
3.18 Laserinterferometersketch. . . . . . . . . . . . . . . . . . . . . . 72
3.19 Illustrationofasinglependulumsubassembly . . . . . . . . . . . 73
3.20 Diagramoftheelectricalsignalflow . . . . . . . . . . . . . . . . 74
3.21 IllustrationoftheDifferentialWavefrontSensing(DWS) . . . . . 75
3.22 Blockdiagramofthemicro-Newtonthrustbalanceassembly . . . 76
3.23 Standardisedmeasurementrunflowchart . . . . . . . . . . . . . 78
3.24 ESCassemblyillustration . . . . . . . . . . . . . . . . . . . . . . 80
3.25 SketchofanElectroStaticComb(ESC) . . . . . . . . . . . . . . . 81
3.26 Figureofapendulumcalibrationrun . . . . . . . . . . . . . . . . 86
3.27 Resultofthependulumcalibration . . . . . . . . . . . . . . . . . 87
3.28 Longtermcalibrationresult . . . . . . . . . . . . . . . . . . . . . 88
3.29 Thrustbalanceperformancesummary . . . . . . . . . . . . . . . 89
3.30 Illustrationofthefrequencysweepused . . . . . . . . . . . . . . 91
3.31 Transferfunctionofthethrustbalance . . . . . . . . . . . . . . . 92
3.32 Postprocessingexample . . . . . . . . . . . . . . . . . . . . . . . 93
3.33 PicturesoftheRITμX . . . . . . . . . . . . . . . . . . . . . . . . 94
3.34 RITμXplumecharacterisationresult . . . . . . . . . . . . . . . . 95
3.35 Transferfunctionofthebalanceconfigurationused . . . . . . . . 96
3.36 Neutralgasthrustmeasurement . . . . . . . . . . . . . . . . . . . 97
3.37 DirectthrustmeasurementoftheRITμX . . . . . . . . . . . . . . 98
3.38 RITμX1μNstepping . . . . . . . . . . . . . . . . . . . . . . . . . 99
3.39 RITμX0:1μNstepping. . . . . . . . . . . . . . . . . . . . . . . . 100
3.40 ThrustnoiseperformanceofthetestedRITμX . . . . . . . . . . . 102
4.1 CrosssectionofEBB20 . . . . . . . . . . . . . . . . . . . . . . . 105
4.2 Summaryofthethrusterperformancesachieveduntil2013 . . . . 106
4.3 EBB20plumeshape . . . . . . . . . . . . . . . . . . . . . . . . . 107
4.4 EBB20magneticfieldtopology . . . . . . . . . . . . . . . . . . . 109
4.5 CrosssectionoftheEBB20MkII . . . . . . . . . . . . . . . . . . 111
4.6 Fluxdensitycomparison . . . . . . . . . . . . . . . . . . . . . . . 112
4.7 MagnetsComparison . . . . . . . . . . . . . . . . . . . . . . . . 113
4.8 NGmagneticfieldgeometry . . . . . . . . . . . . . . . . . . . . . 115
4.9 3Delectrontracinginsidethethruster . . . . . . . . . . . . . . . 116
4.10 DevelopedThrustermodelsillustration . . . . . . . . . . . . . . . 117
4.11 FullsizeNG-μHEMPTillustration . . . . . . . . . . . . . . . . . 118
4.12 PicturesoffiringfullsizeNG-μHEMPT . . . . . . . . . . . . . . 119
4.13 FullsizeNG-μHEMPToperationpointssummary . . . . . . . . . 120
ListofFigures XI
4.14 Thrusterignitionchart . . . . . . . . . . . . . . . . . . . . . . . . 121
4.15 FullsizeNG-μHEMPTthrustmeasurement . . . . . . . . . . . . 122
4.16 FullsizeNG-μHEMPTplumecharacterisationresult . . . . . . . 124
4.17 FullsizeNG-μHEMPTRPAmeasurement . . . . . . . . . . . . . 125
4.18 FullsizeNG-μHEMPTaccelerationefficiency . . . . . . . . . . . 126
4.19 IllustrationofminiNG-μHEMPT . . . . . . . . . . . . . . . . . . 129
4.20 Thrusterdischargechambercomparison . . . . . . . . . . . . . . 130
4.21 PicturesoffiringfullsizeNG-μHEMPT . . . . . . . . . . . . . . 131
4.22 MiniaturisedNG-μHEMPToperationpointssummary . . . . . . 132
4.23 miniHEMPTignition . . . . . . . . . . . . . . . . . . . . . . . . 134
4.24 MiniNG-μHEMPTthrustmeasurement . . . . . . . . . . . . . . 135
4.25 MiniNG-μHEMPTplumecharacterisation . . . . . . . . . . . . 136
4.26 MiniNG-μHEMPTaccelerationefficiency . . . . . . . . . . . . . 138
4.27 miniaturisedNG-μHEMPTthrustnoisemeasurement . . . . . . 140
4.28 SummaryoftheNG-μHEMPToperationspace . . . . . . . . . . 142
5.1 Summaryofthemeasuredthrustnoiseperformances . . . . . . . 150
5.2 IllustrationoftheThrustBalanceMkIV . . . . . . . . . . . . . . 154
5.3 IllustrationofthenewPlasmaDiagnosticAssembly . . . . . . . . 155
1 CombConfiguration . . . . . . . . . . . . . . . . . . . . . . . . . 167
2 ESCdisplacementversusrelativeerror . . . . . . . . . . . . . . . 168
3 ESCdisplacementversusrelativeerror . . . . . . . . . . . . . . . 169
4 ESCdisplacementversusrelativeerror . . . . . . . . . . . . . . . 170