Electric Propulsion Research and Development at NASA-MSFC

Transcription

1 Electric Propulsion Research and Development at NASA-MSFC November 2014 Early NEP concept for JIMO mission Dr. Kurt Polzin Propulsion Research and Development Laboratory NASA - Marshall Space Flight Center

2 Why EP? It flies now and numbers continue to grow. As of

3 Planned NASA EP Activities Past & Planned What has been done? Deep Space 1 technology demonstrator (NSTAR ion engine) Dawn science mission to asteroid belt (ongoing w/nstar ion engine) Asteroid-Retrieval Mission Capture asteroid and return it to cislunar space by ~ m diameter, t object ~40 kw (solar) power level Human Exploration DRM-5 Power manned transfer vehicle for trip to NEA 300 kw (solar) power level Solar Electric Propulsion (SEP) Technology Demonstration Mission Test and validate key technologies required for future exploration elements (i.e. 300-kW solar electric transfer vehicle) by ~2017/2018 ~15-30 kw solar power level on demonstrator 3

4 Recent High-Profile EP Missions ESA s Smart 1 PPS1350G Hall thruster (x1) (Moon) JAXA s Hayabusa 10m microwave ion thruster (x4) (Itokawa sample return) NASA s Dawn NSTAR ion thruster (x3) (Vesta and Ceres) USAF AEHF BPT-4000 Hall thruster (x4) 2010 (Geo Orbit boosted system when bi-prop motor failed) 4

5 Introduction Original seminal work by E. Stuhlinger at MSFC Ion Propulsion for Space Flight (1962) First flight test: SERT-I, 20 July 1964 Current Major Players United States NASA GRC, JPL, MSFC DoD US Air Force, DARPA, AFOSR, NRO, Aerospace Corp. Industry Aerojet, Busek, L3, Boeing, many smaller orgs Worldwide Europe ESA, OHB-Sweden, CNES, Astrium, Alta SpA, SNECMA, Thales JAXA Russia Fakel, Moscow Aviation Institute, TsNIIMash SERT-1 suborbital ion propulsion test Most major comsats today have some form of electric propulsion 5

6 What is Electric Propulsion? Chemical Rocket Chemical Energy Thermal Energy (high entropy) Directed Kinetic Energy Electric Rocket Electrical Energy (refined low entropy) Radiators Power source and converter Thermal Energy (high entropy) Electromagnetic Field Energy (low entropy) Thrusters Directed Kinetic Energy Directed Kinetic Energy The acceleration of gases for propulsion by electrical heating and/or by electric and magnetic body forces. Uses: Orbit raising, momentum dumping, stationkeeping, primary propulsion Thrust level dependent on available power 6

7 R&D Area In Use Early Types of Electric Propulsion Electric thrusters are generally categorized by their primary acceleration mechanism: Electrothermal Electrical energy into thermal energy Large number of all EP systems on-orbit I sp s, thrust medium/high Hot exhaust / high density gas / nozzled expansion Resistojet Electrostatic Applied electric field directly accelerates ions Growing fraction of all EP systems in space I sp ,000 s, thrust low/medium Low density gas / grid or electrodes to apply E-field / low thrust density Electromagnetic (Plasma) Interacting currents and magnetic fields directly accelerate plasma I sp s, thrust medium/high High density gas / generally compact Hall thruster Magnetoplasmadynamic thruster MSFC R&D on iodine-fed Hall thrusters, high-power arcjets (1 MW) and high-power pulsed inductive thrusters (PIT). 7

8 Iodine Satellite (isat) Advantages of Iodine o Increased Isp*density (compared with traditional gaseous propellants like Xe) o Low storage / working pressure 8

9 Iodine Satellite (isat) Emerging Market in SmallSats o Transfers to higher value science / operations orbits o Operationally Responsive Space o Extend mission life / drag make-up o 25-year de-orbit requirement Limitations on SmallSats (as secondary payloads) limit primary propulsion options o Limitations on volume, mass, power o Limitations on hazardous and stored energy from propellants o Limitations for high pressure systems o Systems must sit idle for unknown periods before integration with launch vehicle 200W Hall thruster infusion mission (near-term, low cost risk reduction) o Short mission duration, low throughput, simplified propellant management o Engineering / materials changes and validation (thruster, valve wetting surfaces and seals) o Demonstrates enabling technology, demonstrates high spacecraft power density 9

10 Inductive Pulsed Plasma Thrusters Conical theta pinch IPPT o Small (~20 cm diameter) apparatus o Designed to examine effect of cone angle on propellant utilization o Demonstrated 5 Hz, 2.5 kw average power throughput (record for energy storage in the 100s of J/pulse range) Conical theta pinch Flat-plate IPPT Flat-plate IPPT o Small (~30 cm OD) testbed thruster o Pulsed gas valve and solid state switching incorporated o To date, demonstrated 2-Hz operation, with higher repetition rates possible PIT MkVI o High power thruster (4.5 kj/pulse operation) o Originally fabricated in 2001 at NGST o Refurbishment continues at MSFC, plans to operate in single shot and repetition-rate mode up to 40 kw (~9-10 Hz) PIT 10

11 Electronegative Thruster No cathode to become damaged or erode Beam neutralization by alternatively accelerating packets of positive and negative charge MSFC work to be the first to perform direct thrust measurements on such a device 11

12 Contact Dr. Kurt Polzin Propulsion Research and Development Laboratory NASA-Marshall Space Flight Center 12

13 Back-Up Slides 13

14 EP Thrusters - Electrothermal Electrothermal Thrusters Heat propellant and expand through a nozzle Resistojet Heating element heats gas flow Power typically < 1-kW Thrust < 1-N, I sp < 600-s Satellite station-keeping in-flight (e.g. Olin MR-501: 500-W, 300-s) Typical Propellants: Hydrazine, Ammonia Arcjet Electric arc heats gas flow Power typically < few-kw Thrust < 2-N, I sp < 1500-s Station-keeping, orbit maneuvers in-flight (e.g. Olin MR-510: 2-kW, 600-s) Typical Propellants: Hydrazine, Ammonia MSFC work on research-level high power arcjets (1MW, 1500s, 20 lb f on H 2 and ammonia)v 14

15 EP Thrusters - Electrothermal Variable Specific Impulse Magnetoplasma Rocket (VASIMR) Operation composed of 3 main subsystems 1. Ionizer 2. Booster 3. Magnetic Nozzle Neutral Gas Turn neutral gas to plasma Add Energy to Ions Convert perpendicular energy to thrust High Energy Ions Electrical Energy Electrical Energy Electrodeless, quasi-neutral plasma propulsion capable of using various propellants and operating at variable specific impulse at constant power. (thrust inversely proportional to I sp ) VX-200 test firing research level. Thruster operated in pulsed mode at 200 kw e in vacuum chamber. Issues: overall system efficiency /specific mass, RF power processing for high power operation Deep-Space Manned / Cargo missions 15

16 EP Thrusters - Electrostatic Electrostatic Thrusters High voltages directly accelerate ions Ion Thruster Voltage generated by high voltage grids Power typically < 20-kW Thrust < 0.5-N, I sp < 5000-s Station-keeping; LEO-GEO; deep space in-flight (e.g. NASA NSTAR: 2.5-kW, 3300-s) Typical Propellant: Xenon Hall Thruster Voltage concentrated by trapped electrons Power typically < 50-kW Thrust < 1-N, I sp < 3000-s Station-keeping, LEO-GEO, LEO-Lunar in-flight (e.g. BPT-4000: 4.5-kW, 1850-s) Typical Propellants: Xenon, Krypton Alternate Propellants: Iodine, Bi, Mg MSFC examining Iodine Hall (solid propellant substitute) / partners w/busek, GRC 16

17 EP Thrusters - Electromagnetic Electromagnetic Thrusters Use Lorentz (jxb) force to accelerate plasma Magnetoplasmadynamic (MPD) High power, high thrust density Thrust ~ 1-10 s N, I sp ~ 2500-s to >10000-s Orbit raising, primary propulsion for planetary research level (~ 250-kW steady-state, > 1 MW quasi-steady) Propellants: Argon, Hydrogen, Lithium Pulsed Plasma Thruster (PPT) Low continuous power, precise impulse bits Impulse < 0.3-N-s, I sp ~ 2500-s to >10000-s Station-keeping, drag make-up in-flight (e.g. LES-9: 30-W, 1000-s) Typical propellant: Teflon Pulsed Inductive Thruster (PIT) High power, high thrust density Electrodeless (needs high power switches) Impulse < 0.1-N-s, I sp ~ 2000-s to >10000-s Orbit raising, primary propulsion for planetary research level (tested in single-shot operation) Typical propellants: Ammonia, In-Situ propellants 17