AFRL MicroPPT Development for Small Spacecraft Propulsion

Spanjers, Gregory G.; Bromaghim, D. R.; Lake, James; Dulligan, M. J.; White, David; Schilling, John H.; Bushman, Stewart S.; Antonsen, Erik L.; Burton, Rodney L.; Keidar, Michael; Boyd, Iain D.

doi:10.2514/6.2002-3974

Cited by 32 publications

(17 citation statements)

References 6 publications

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“…PPTs are well developed, and pursued by the National Aeronautics and Space Administration (NASA) [11] and the Air Force Research Laboratory (AFRL) [12]. Typical PPT parameters are a few hundred to 1000 s specific impulse, power of 2.5 to 20 W, impulse bits from 26 to 860 mN-s, thrust of 0.027 to 4.45 mN, specific power of 66 W/mN, and mass of 0.5 to 8 kg for thruster and fuel.…”

Section: A Micropropulsionmentioning

confidence: 99%

Ion acceleration in a radio frequency driven ferroelectric plasma source

Kovaleski

2005

IEEE Trans. Plasma Sci.

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Ion emission from ferroelectric plasma sources driven by radio frequency (RF) applied voltage is studied. An experimental investigation of particle emission from lead zirconate titanate ferroelectric ceramics driven by bursts of seven cycles of RF voltage at 248 kHz has revealed significant ion current emission. Measured electron to ion peak current ratios ranged from 11 to 19, which is much lower than the expected thermal current ratio. These results indicate that the ions are being preferentially accelerated. An analysis of the ponderomotive force on the ions and electrons reveals that it may be responsible for acceleration of the ions. The ferroelectric plasma is examined as a possible micropropulsion thruster. Performance estimates based on the ponderomotive acceleration calculations predict specific impulse of 2000-3000 s, thrust of 0.1-1 mN, and specific power of 15 W/mN. These estimates are compared to existing micropropulsion concepts, revealing the attractiveness of ferroelectric plasma sources.

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Section: A Micropropulsionmentioning

confidence: 99%

Ion acceleration in a radio frequency driven ferroelectric plasma source

Kovaleski

2005

IEEE Trans. Plasma Sci.

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“…In particular, the US Air Force has a growing interest in highly maneuverable microsatellites to perform various missions, such as space-based surveillance, on-orbit servicing, inspection, space control etc. 2 From a propulsion point of view, these missions require spacecraft propulsion systems that can deliver high thrust or high specific impulse. Recently, an electromagnetic PPT was successfully operated for pitch axis control on the EO-1 spacecraft.…”

Section: Introductionmentioning

confidence: 99%

Plasma Generation and Near Field Plume of a Micro-pulsed Plasma Thruster

Keidar

Boyd

2003

39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit

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In this work we report on progress in the development of models for a Micro-Pulsed Plasma Thruster (µPPT) and its exhaust plume. As a working example we consider a µPPT developed at the Air Force Research Laboratory. This is a miniaturized design of the axisymmetric PPT with a thrust in the 10 µN range that utilizes Teflon TM as a propellant. The plasma plume is simulated using a hybrid fluid-PIC-DSMC approach. The plasma plume model is combined with Teflon ablation and plasma generation models that provide boundary conditions for the plume. This approach provides a consistent description of the plasma flow from the surface into the near plume. The magnetic field diffusion into the plume region is also considered and plasma acceleration by the electromagnetic mechanism is studied. Teflon ablation and plasma generation analyses show that the Teflon surface temperature and ablation rate are strongly non-uniform in the radial direction and have a maximum near the central electrode. As a result the propellant surface has the form of a cone with an apex at the central electrode. Analysis predictions for the ablation depth as well as the ablation profile shows close correspondence to experimentally observed dependencies. Longterm operation is associated with propellant and central electrode recession. To this end a model of the plasma flow inside of the anode tube is developed. Some preliminary results are reported. Electron and neutral densities predicted by the plume model are compared with near field plume measurements using a two-color interferometer and good agreement is obtained.

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“…Ereference = Eei(CO+CA )t (4) where co is the laser frequency, COA is the acoustic frequency of the Bragg cell, 0 is the phase shift due to plasma and neutral density, and y(x,y) represents a phase distortion across the beam diameter. The total electric field at the detector is the sum of these components.…”

Section: Escene = Esei(cat+±(t)+y(xy))mentioning

confidence: 99%

“…4 Conventional interferometer configurations were incapable of transmitting the multiple laser passes needed to make a quantitative density measurement through the small scale length plasma.…”

Section: Introductionmentioning

confidence: 99%

Herriott Cell augmentation of a quadrature heterodyne interferometer

Antonsen

Burton

Spanjers

et al. 2003

Review of Scientific Instruments

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)2 ABSTRACT A quadrature heterodyne interferometer is augmented with a Herriott Cell multi-pass reflector to increase instrument resolution and enable a separation of the phase shift due to neutral density from room vibrations. In addition, the use of the Herriott Cell enables variations in the multi-pass laser-beam geometry that optimizes the diagnostic for small scale length measurements or for planar measurements. Ray tracing analysis is used to illustrate retro-reflective planar measurement geometries attainable with the instrument.Analysis is performed to show that phase front degradation and loss of scene beam intensity, concomitant with the large number of reflections from the Herriott Cell mirrors, does not introduce a systematic measurement uncertainty. The diagnostic capability is demonstrated with measurements of the electron and neutral densities in the plasma exhaust from electric propulsion thrusters. Experimental data with up to 18 passes through plasma demonstrates that the instrument resolution to electron and neutral density increases almost linearly with number of passes. However, measurement uncertainty associated with room vibrations is shown to remain constant as the number of passes is increased. Therefore the Herriott Cell can be used to increase the signal of neutral density phase shifts relative to the noise of the phase shifts due to room vibrations. For the Pulsed Plasma Thruster plasma exhaust used to validate the instrument, the addition of the Herriott Cell reduces the density measurement uncertainty to equal or less than the uncertainty due to discharge irreproducibility. When used on plasma sources with higher reproducibility, the Herriott Cell interferometer should be an effective tool for high resolution electron and neutral density measurements.

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AFRL MicroPPT Development for Small Spacecraft Propulsion

Cited by 32 publications

References 6 publications

Ion acceleration in a radio frequency driven ferroelectric plasma source

Ion acceleration in a radio frequency driven ferroelectric plasma source

Plasma Generation and Near Field Plume of a Micro-pulsed Plasma Thruster

Herriott Cell augmentation of a quadrature heterodyne interferometer

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