Electric Propulsion in Low Temperature Co-Fired Ceramicsf(First year of Three)DonPlumlee, Mechanical and Biomedical Engr.Don Plumlee, Mechanical and Biomedical Engr.Jim Browning, Electrical and Computer Engr.Sin Ming Loo, Electrical and Computer Engr.ISkMhil dBi dilEInancSenocak, Mechanical and Biomedical Engr.Amy Moll, Materials Science and Engr.NASA Contact: Valerie Lyons, NASA Glenn Research CenterNASA Technical Advisor: Dan Herman, NASA Glenn Research CenterProject PI, David Atkinson, University of Idahoj, , yOutlineOutline Micro-Propulsion IntroductionProject OverviewProject Overview Systems ApproachTest ApparatusTest Apparatus Thruster Body Low Temperature Co-Fired Ceramics (LTCC) Inductively Couple Plasma (ICP) Source Prototype ThrusterElectrical Support SystemElectrical Support System Mechanical Support System SummaryEvolution of SMALLSMALL Satelliteshttp://www.space.t.u-tokyo.ac.jp/cubesat/index-e.htmlFedSat, Australia•Launched on a Japanese HII-A fromhttp://www.auspace.com.au/projects/fedsat.htm“CubeSat” XI-IV, Univ. of Tokyo•Launched from thePlesetsk•Launched on a Japanese HII-A from Tanegashima Japan in 2002• Mass ~ 50 kg • Sides ~ 50 cm each •Launched from the PlesetskCosmodrome in 2003• Mass ~ 1 kg• Sides ~ 10 cm eachThese small satellites need small propulsion systems.Micro-Propulsion CategoriespgElectric Thrusters Chemical ThrustersMonopropellant Thruster in siliconHall Effect Thruster (NASA)Micro-Ion Engine (JPL)Solid Propellant Thruster in siliconCold Gas Thruster using compressed Butane(SNAP-1)Field Emission Electrical Propulsion in silicon(SNAP-1)Project OverviewProject OverviewDevelop small gridded ion thrusterDevelop small gridded ion thruster (plasma thruster) Satellite Station keepingNanosatellitesNano-satellites 30kg target satellite mass Use high frequency (500 to 1000 MHz) ICP plasma sourceICP plasma source Use LTCC for thruster body to protect antenna from plasmaDl i tltt tDevelop experimental test apparatus Develop a miniature on-board control systemThruster RequirementsConceptual Satellite with 12 thrusterswith 12 thrustersA target mass of 40 kg and a target gggthrust of 200uN was selected.Thruster System: SchematicTest Apparatus/Arm Thruster DeviceThruster Support System3.7 VDCCommon-1000 VDC10 VDCBattery/PSGNDAccelerator GridScreen GridPower BoardRS232 -SerialRF @ ~900MHzControllerGNDAntennaControl Board(Optional)Argon (25psia)Argon (1psia)Argon TankArgon PortRegulator/Latch Valve/FilterPower Board500 VDCGNeutralizer GND(External)Thruster System: Design ConceptInternal Support System SideExternal Thruster SideTest Apparatus: Vacuum Chamber Vacuum chamber is used to simulate a space environment. 29 ” 2 ” Interior cylinder dimensions: 29.5” D x 24” L Currently capable of operating in the 10-7Torr range. (Atmospheric pressure is ~760 Torr.) Future operating pressure of 10-7Torr after rebuilding cryopump.Test Apparatus: Summer 2010Test Apparatus: Thrust Arm Simulation 500 uN thrust for 30 seconds from 1 kg thruster package k = 0.231 Nm/rad c = 0.01 Nms/radTest Apparatus: Thrust Stand DesignRiverhawk Flex PivotsSimple Pendulum Thrust StandSimple Pendulum Thrust StandPhiltec fiber optic, reflectance-dependant displacement Nid l ti f 0 015sensor. Near-side resolution of 0.015 μmTest Apparatus: Electrical Control SystemThruster: Design Concept Entire mechanical structure df LTCCmade from LTCC Spiral antenna used to generate plasma (500 MHz to 1 GHz) Argon gas Screen grid shield accelerator grid Accelerator grid extracts ions to 1000 eV Field emission electron source neutralizes beam (not shown)Thruster: Low Temperature Co-fired C i (LTCC)Ceramics (LTCC) LTCC is a Glass/Alumina mixture that sinters at Low Temperature (< 900°C) The Ceramic substrate andThe Ceramic substrate and embedded elements are Co-Fired in one step. Material in the “green” state is composed of Glassis composed of Glass, Alumina and Organic binder Raw LTCC is delivered as a flexible sheet called “Green ”Tape”Forms single structure after firingThruster: LTCC Fabrication ProcessChannel FabricationProcess200µmThruster: C-MEMS LaboratoryApplicationsApplicationsCapacitively Coupled Plasma DeviceIon Mobility SpectrometerMicro-Combustion Device(H2and air)Micro-Nozzles (1mm x 0.2mm)Thruster: Inductively Coupled Plasma (ICP) Source(ICP) Source Used in semiconductor industry for etch and PECVD (13 56 MHz)(13.56 MHz) Some small sources demonstrated (Hopwood)(p ) Power transfer is inductive Coupling through thin di l t itt tdielectric –protects antenna substrate from ion bombardmentLTCC Antenna modelThruster: ICP Fabrication in LTCCSpiral antenna2 cm diameter ICP devices fabricated in LTCC 7 LASER Cut LTCC Layers Center hole used for propellant injection. Top layer is 50µm thick ceramic Silver traces with 100µm width installed using Nscrypt Direct Write tool A variety of designs produced varying:TurnsTurns Diameter CSAM tool used to inspect embedded features. (Courtesy of Plexus)CSAM imageThruster: Preliminary ICP CharacterizationCharacterizationPreliminary COMSOL Modeling• Multiphysics Modeling and Simulation SoftwareExperimental Results• electric field generated by the antenna is obtained using a 2-dimensional stepper tt f tildjt td• 3D modeling of antenna• Uses Finite Element Method• Simulations run at 960MHz to analyze E-Field Intensitymotor stage for spatial adjustment, and a HP spectrum analyzer for field measurements. • Using an automated LabVIEWanalyze EField Intensity• Plasma Module will allow analysis of plasma initiationapplication to coordinate stepper motor movements with field measurements. It is possible to obtain field measurements with 0.5mil spatial resolution.Thruster: ICP Operational Results Antenna operation 500 MHz to 1 GHz  pressures from 10 mTorr to 1 TorrSt t 520 WStart power ~ 5-20 W Sustain power ~ 0.5 WThruster: ICP Start Power Vs FrequencyStart Power vs Frequency50603040 Power (W)100 mTorr200 mTorr300 mTorr400 mTorr500 mTorr1020Start500 mTorr600 mTorr700 mTorr800 mTorr900 mTorr010400 500 600 700 800 900 1000 1100Frequency (MHz)1 TorrFrequency (MHz)Thruster: ICP Minimum Sustain Power vsFrequencyFrequency1.2Stop Power vs Frequency1100 mTorr0.60.8op Power (W)100 mTorr200 mTorr300 mTorr400 mTorr500 mTorr0.20.4Sto600 mTorr700