MINOTOR H2020 project for ECR thruster development D. Packan, P.Q. Elias, J. Jarrige, T. Vialis, S Correyero, S. Peterschmitt, ONERA M. Merino, A. Sánchez-Villar, E. Ahedo UNIVERSIDAD CARLOS III DE MADRID G. Peyresoubes, THALES MICROELECTRONICS K. Holste, P. Klar, JUSTUS-LIEBIG-UNIVERSITAET GIESSEN M. Bekemans, T. Scalais, E. Bourguignon (THALES ALENIA SPACE BELGIUM S. Zurbach, SAFRAN AIRCRAFT ENGINE M. Mares, A. Hoque, P. Favier, L UP
Content Context MINOTOR technology: ECRA Objectives and structure of MINOTOR Achievements of Work Packages 2
Context of MINOTOR #
MINOTOR context Importance of electric propulsion recognized by the European Union: created a structure of Call for Proposals on that topic SRC: Strategic Research Cluster, managed by a PSA: Program Support Activity (support and advice). Name of the PSA: EPIC EPIC: Electric Propulsion Innovation and Competitiveness http://epic-src.eu/ EPIC Consortium: ESA (coordinator), ASI, BELSPO, CDTI, CNES, DLR, UKSA, Eurospace, SME4Space 4 MINOTOR (MagnetIc NOzzle electron cyclotron Resonance thruster) Selected in call RIA H2020-COMPET-3-2016-b SRC - In-Space electrical propulsion and station keeping - Disruptive Technologies Consortium: 7 partners, 4 countries http://www.minotor-project.eu/ 3 years: 01/2017 to 12/2019
Consortium Participant no. Participant organisation name Participant short name Country 1 (CO) Office National d'etudes et de Recherches Aérospatiales ONERA France 2 Universidad Carlos III de Madrid UC3M Spain 3 Thales Microelectronics SAS TMI France 4 Justus-Liebig-Universitaet Giessen JLU Germany 5 Thales Alenia Space Belgium SA TAS-B Belgium 5 6 Safran Aircraft Engines SAFRAN France 7 L-UP SAS LUP France
MINOTOR technology #
ECR Thruster Principle ECR source + Plasma acceleration in a magnetic nozzle ECR effect: application of an EM field at electron cyclotron frequency at 2.45 GHz, B=875 Gauss ce eb m e Efficient ionization of the propellant gas Principle of operation: ECR discharge heats the electrons (10s of ev) Hot electrons «blow up» the plasma Ions follow (dense plasma) More electrons acceleration: gyrokinetic conversion 7 neutral plasma coming out cathodeless thruster
Thruster physics: position among electric thrusters Thrust Thrust Thrust Thrust B E E B Magnetic nozzle E B E GIE FEEP ES BP-ES BP-GIE HET HEMP MPD PPT PIT ECR HPT ICR (VASIMR) 8 Electrostatic thrusters GIE = Gridded Ion Engine FEEP = Field Effect Electric Propulsion ES = ElectroSpray (=colloid) BP = bipolar HET = Hall Effect thruster HEMP = High Efficiency Multistage Propulsion Neutralizerless («cathodeless») thrusters MPD = Magneto Plasma dynamics PPT = Pulsed Plasma Thruster PIT = Inductive Plasma thruster ECR = Electron Cyclotron Resonance HPT = Helicon Plasma thruster ICR = Ion Cyclotron Resonance
Detailed advantages of ECRA Characteristics System impact Advantage Lower recurring cost No Neutralizer Removal of the neutralizer as a critical component (failure, lifetime) Simplified PPU Single fluidic line Higher reliability Longer lifetime Lower recurring cost Higher reliability Lower recurring cost Lower recurring cost (ground testing) Low Xe purity acceptable Lower cost of flight propellant No fragile or complex parts (no grids, etc...), low part number Magnetic nozzle Microwave power = only electrical input Reacting gases acceptable (e.g. O 2 ) Simple design Thrust vectoring Ambipolar acceleration Magnetic shielding Simplified PPU DC uncoupling of thruster and PPU MW generator = new element in PPU Lower cost Xe tank Compatible with air breathing Compatibility with all alternative propellants. Lower recurring cost Higher reliability Longer lifetime Lower recurring cost (no gimbal mount needed) No Child law limit to thrust per unit area (similar to HET) High efficiency Longer lifetime Lower recurring cost Lower recurring cost (no galvanic isolation of PPU) Increases cost 9
Technical hurdles PPU efficiency: off-the-shelf microwave generators have efficiencies < 70% there are new solid state solutions emerging with up to 90% efficiency at low power (~5W). Magnetic torque: the DC magnetic field created by the permanent magnets using thrusters in pair, with reversed magnetic field, or placing a magnet creating an opposite torque on the satellite plateform. EM field: low emission when plasma ON (not visible on detector). Needs to be quantified. 10 Magnet heating: current permanent magnet technologies (samarium-cobalt for example) can go to high enough temperatures Reflected power: some theories on ECR thruster show 50% power reflection: only the RCP wave (right circularly polarize) would be absorbed. experimentally we routinely achieve 95%. No show stopper
Developing an ECR Thruster : challenges - Plasma physics more complex than other thrusters (wave/ionisation/acceleration coupling): difficult to model. Full model not yet available. Magnetic nozzle challenging. IONIZATION AND ACCELERATION ZONES Growing modeling difficulty DC FREQUENCY MHz or pulsed µs ( >L) Separated GIE ICR-VASIMR Coupled HET HEMP MPD HPT PPT PIT - No direct experimental knowledge of the total current and of the ion energy: need for ion beam probes and very refined experimental characterization GHz ( <L) ECRA 11 - Good vacuum levels needed: magnetic nozzle much larger than the source and extends in the vacuum tank. need to be < 10-5 mbar (HET can work up to 10-4 mbar) need 10 times higher pumping
Example of parameters to investigate Magnetic topology: larger ECR zone (parallel B region) magnetic mirror at the exit: control of energy, better ionization magnetic mirror at the entrance: reduce losses to back wall B field variations at the exit: vectoring Microwave coupling: antenna, waveguide,. Develop low and high impedance coupling (issue of matching) 12 Effect of frequency: try 4 GHz, 1 GHz Effect of wall material: conductive vs dielectric, spuutering/secondary emission yield, Effect of scale-up : 200W then 1 kw One of the questions for scale up: should the wavelength (ie frequency) scale with the thruster?
ECRA thruster configuration Current tested conditions and dimensions (constrained to the available hardware and facilities currently at ONERA) MW Frequency = 2,45 GHz ECR conditions at 875 Gauss 0,1 to 0,4 mg/s of Xenon 10 to 50 Watts currently tested 2-3 cm diameter current dimensions Scalable to lower and higher power (kw) 13 13
Experimental measurements 1,0 0,8 0,6 0,4 0,2 0,0 0 100 200 300 400 Ion energy [ev] Xe + Q m (Xe): 0.06 mg/s 0.1 mg/s 0.15 mg/s 0.2 mg/s 0.3 mg/s Gas Xenon Mass Flow Rate (mg/s) 0.1 Power absorbed (W) 30.0 Ion energy (ev) 250 Ion ideal Isp (s) 1950 Ion current (ma) 45 Thrust (mn) 0.98 Isp (s) 993 Mass utilization efficiency (%) 61 Power efficiency (%) 38 Divergence efficiency (%) 83 Thruster total efficiency (%) 16 14 Xe 2+ 0 20 40 60 80 100 120 140 m/z
Performance perspectives 15
Objectives and structure of MINOTOR #
Objectives of MINOTOR Status at start of project: TRL 3, short tests at 30W, a few configurations tested Main objectives (thruster and PPU): - Understand the physics - Demonstrate performances, and extrapolate 17 - Determine possible uses: GO/NO GO - Prepare development roadmaps ~ Go to TRL 4
Relations between WPs 18
Content of Work Packages WP2: Management WP3: Modeling WP4: Thruster design optimization WP5: Alternative propellants Leader: L-up Project progress monitoring and control Coordination of administrative, financial and quality management Dissemination, communication, exploitation Leader: UC3M Code developments: SURFET (hybrid), ROSEPIC (full PIC 3D) Parametric studies on thruster design Leader: ONERA Experimental design studies Thruster geometry Wave coupling strategies Frequency effect Magnetic field topology Thrust vectoring Leader: ONERA Numerical performance and design studies Experimental tests: determination of performances 19 WP6: Scale-up and erosion WP7: MW generator WP8: System impact Leader: JLU Numerical modeling of the scale-up Scaled-up designs 200W and 1 kw tests Comparison of 2 facilities (ONERA, JLU) Erosion tests at 200W: 1000 hours Leader: TMI Demonstration of a high efficiency MW technology Elementary amplifier Combiner structure High power generator (100W) On-thruster demo (50W level)) Leader: TAS-B PPU impact: MW PPU structure and cost/reliability advantages Thruster impact: reliability, cost, Roadmaps: thruster and PPU WP9: Requirements and validation Leader: ONERA Performance status check along the project advancement Global roadmap for the thruster technology (toward SRC call 2)
Work package achievements #
WP3 Modeling: hybrid code The hybird code (fluid+pic) tailored to the ECR thruster is being developped by UC3M. The SURFET code is subdivided in 4 modules: Plasma-wave interaction module: 2D cold-plasma dielectric tensor code (module #1 of SURFET). Kinetic submodels and/or information from ROSEPIC will be used to model accurately the resonance regions. Ion/neutral PIC-DSMC subcode: 2D quasi-structured Particle-In-Cell code based on magnetic grid. Will include ionization, recombination, excitation and transport dynamics Electron fluid subcode: magnetized electron fluid with energy balance. Fluid electrons (instead of PIC) reduce substantially the computational complexity, at the expense of a minor loss of physical detail Magnetic nozzle module: two-fluid, 2D code of the plasma expansion in the magnetic nozzle 21 Perfect conductor PML Magnetoplasma options: Cold + collisions Kinetic damping j a B 0 IEPC-2017-105 Preliminary version of Wave-plasma module planned for M12 Ongoing work IEPC-2017-106 Ongoing work
22 WP3 Modeling: PIC code Development of a PIC/MCC code ES-PIC for Low pressure plasma modeling DSMC capability: vacuum chamber analysis EM-PIC for ECRA Features : Serial / 2-level parallelism (MPI/ OpenMP) Block cartesian mesh Arbitrary geometry : immersed boundary method Tiled structure Vacuum chamber simulation, 72 cores ~ 7.10 6 particles 22 Status of the Code All particle modules developed 3D DSMC test done Maxwell Solver : 1D done 2D 3D parallel version under development P.Q. Elias, Advances in the kinetic simulation of the microwave absorption in an ECR thruster, IEPC-2017-361 1D PIC modeling
WP4: Thruster design optimization (1/2) The goal is to improve the understanding and performances (efficiency, thermal management, lifetime) Achievements: - Developped a thrust balance measurement for reliable performance assessment (waveguide-to-coax feedthrough with no mechanical force) - Parametric experimental study: antenna length, diameter, source length Antenna length 23 Antenna diam. - Effect of background pressure Source length.
WP4: Thruster design optimization (2/2) - Measurement of plume properties, with Langmuir / Faraday probes - Combination with LIF measurements Achievement: Measurement of acceleration voltage profile - Development of new techniques: plasma diamagnetism 24 Achievement: Measurement of perpendicular electron temp. (anisotropic distribution)
WP6: Scale up and erosion Thrust balance for high power thruster in JUMBO facility: cannot measure 5mN for 200W test in MINOTOR. Achievement: A thrust balance dedicated to low thrust measurements (1-10 mn) has been acquired, to be used for MINOTOR. It was manufactured by the Advanced Space Technology (AST) company, shared between German Space Center (DLR) Goettingen and JLU Giessen. It consists of an aluminium frame onto which a parallelogramstructure is attached by (bending) bearings. The thrust is measured by a moving coil method where a counterforce is generated which compensates the thrust. Ongoing work: Tests with coil steps 1-10 mn Integration of the thrust balance into the Jumbo test facility Assessment of the quality of the calibration scheme Thrust measurements with a RIT-10 Determination of thrust balance parameters (resolution, temperature drifts, offset, etc) 200W scale-up work at ONERA 25
WP7: MW generator PPU efficiency is a major factor in the thruster system efficiency. No off-the-shelf MW generator with higher than 60-70% eff. BUT new technology + Thales patent can reach high power 85-90% efficiency. To be developped in WP7. 26 90% efficient. Structure of the microwave generator planned for MINOTOR. Achievement: 25W PA 60% efficiency so far, efforts to improve the efficiency ongoing.
WP8: System Impact Focus on the simplification of the PPU: ECRA requires: - No cathode - No coil - No galvanic isolator (thruster floating) HET ECRA Achievement: 27 Saving of >50% of the PPU Cost. But need to add MW amplifier Cost (SSPA).
WP9: Requirements and validation Ongoing work: - Gathering reference data for thruster performance comparison - Following ECRA performances. Setup a server to put thruster data for sharing between experimental and modeling teams 28
Conclusion MINOTOR has made good progress, in line with expected advancement. Several achievements in the different work packages. 2 journal publications in preparation 8 papers at IEPC-2017: - D. Packan et al., The MINOTOR H2020 project for ECR thruster development, IEPC-2017-547 - J. Jarrige, S. Correyero-Plaza, P.Q. Elias, D. Packan, Investigation on the ion velocity distribution in the magnetic nozzle of an ECR plasma thruster using LIF measurements, IEPC-2017-382 - S. Correyero-Plaza, J. Jarrige, D. Packan, E. Ahedo, Measurement of anisotropic plasma properties along the magnetic nozzle expansion of an Electron Cyclotron Resonance Thruster, IEPC-2017-437 - T. Vialis, J. Jarrige, D. Packan, Geometry optimization and effect of gas propellant in an electron cyclotron resonance plasma thruster, IEPC-2017-378 - P.Q. Elias, Advances in the kinetic simulation of the microwave absorption in an ECR thruster, IEPC-2017-361 - M. Merino, A. Sanchez-Villary, E. Ahedo, P. Bonoli, J. Lee, A. Ram and J. Wright., Wave Propagation and Absorption in ECR Plasma Thrusters, IEPC-2017-105 - G. Sanchez-Arriaga, J. Zhouy, E. Ahedo, M. Martnez-Sanchez and J.J. Ramos, One-dimensional Direct Vlasov Simulations of Non-stationary Plasma Expansion in Magnetic Nozzle, IEPC-2017-106 (partial funding) - M.Wijnen, S.Correyero-Plaza, N.Aguera-Lopez, D.Perez-Grande, Innovative Electric Propulsion trends, concurrent mission design and enabling technologies for a bold CubeSat Lunar Positioning, Young Visionary paper award, IEPC 2017 (partial funding) - asystem 29
ECRA at startup 30
Thank you for your attention ECR thruster (coil version) operating with different gases 31 This work was made in the framework of project MINOTOR that has received funding from the European Union s Horizon 2020 research and innovation program under grant agreement No 730028.