Download or read book Pulsed Plasma Thruster Plume Diagnostics written by Robert Eckman and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plume Diagnostics in Pulsed Plasma Thruster written by Naoki Kumagai and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Resolution Laser Diagnostics in Millimeter Scale Micro Pulsed Plasma Thrusters written by and published by . This book was released on 2002 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: A class of Micro-Pulsed Plasma Thruster (MicroPPT) is being developed to provide precise attitude control and stationkeeping ability to 25-kg class satellites. Operating by means of a surface discharge across a Teflon propellant fuel bar only a few millimeters in diameter, the MicroPPT delivers a thrust-to-power ratio of 5 - 10 Micro-N-s/J. Due to the low pulse energy and size, the MicroPPT produces a spatially confined and diffuse plasma plume that is difficult to analyze with material probes for validation of plume modeling. To this end, a Herriott Cell interferometer is introduced to measure the plume electron and neutral densities. By focusing a large number of laser beams into a small measurement volume, the Herriott Cell can increase the instrument resolution by a factor of about 10, compared to a single-pass interferometer, with minimal degradation of spatial resolution. Comparison of these results with a 2 colors, 2-pass interferometer demonstrates experimental validity of the point measurement technique used. Comparison of the measured electron density with modeling predictions by Keidar and Boyd shows close agreement. Attempts to measure the MicroPPT neutral density with a 2 colors configuration of the Herriott Cell interferometer were inconclusive, in spite of previous successes using this technique on larger PPTs.
Download or read book Experimental and Theoretical Analysis of Pulsed Plasma Exhaust Plumes written by Dominic J. Palumbo and published by . This book was released on 1978 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulsed plasma plume diagnostic studies performed in the past have shown that considerable uncertainty exists because of the degree of backscatter encountered in ground test facilities. The large level of backscatter is attributable to the extremely high mass expulsion rate characteristic of solid propellant pulsed plasma thrusters (30 to 40 g/s on the average). The study reported upon herein had the objective of obtaining a suitable analytic model and computational scheme for calculation of the plume characteristics of a 23 mN-s pulsed plasma thruster. The calculated results were compared to experimental measurements of electron number density and temperature, obtained using specially designed Langmuir probes, only up to the point in the time when backscatter of plume effluents off the vacuum chamber walls became significant. A secondary objective of the program was to design a suitable driver circuit for the Langmuir Sangmuir probes so that a voltage ramp could be pulsed for one microsecond at any given time subsequent to thruster discharge initiation and the volt-ampere characteristic could be displayed on an XY oscilloscope.
Download or read book Advanced Diagnostics for Millimeter Scale Micro Pulsed Plasma Thrusters written by and published by . This book was released on 2002 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: A class of Micro-Pulsed Plasma Thrusters (MicroPPTs) is being developed by the Air Force Research Laboratory (AFRL) to provide precise attitude control and stationkeeping ability to 25-kg class satellites. Operating by means of a surface discharge across a Teflon(TM) propellant fuel bar only a few millimeters in diameter, the MicroPPT delivers a thrust-to-power ratio of 5 - 10 microN-s/J. Due to the low pulse energy and size, the MicroPPT produces a spatially-confined and diffuse plasma plume that is difficult to analyze with material probes. Efforts to characterize MicroPPT plume are underway. To this end, a Herriott Cell interferometer is introduced to establish the plume electron and neutral densities. Comparison of the measured electron density with modeling predictions shows close agreement. Additionally, a Pockels cell has been developed to provide a zero-impedance MicroPPT breakdown voltage measurement. Current research focuses on an infrared-emission measurement capability to determine propellant surface temperature during thruster operation.
Download or read book Pulsed Plasma Thruster Plume Study Symmetry and Impact on Spacecraft Surfaces written by Lynn A. Arrington and published by . This book was released on 2000 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thruster Plume Plasma Diagnostics written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-24 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although detailed near field (0 to 3 cm) information regarding the exhaust plume of a two kilowatt arc jet is available (refs. 1 to 6), there is virtually little or no information (outside of theoretical extrapolations) available concerning the far field (2.6 to 6.1 m). Furthermore real information about the plasma at distances between (3 to 6 m) is of critical importance to high technology satellite companies in understanding the effect of arc jet plume exhausts on space based power systems. It is therefore of utmost importance that one understands the exact nature of the interaction between the arc jet plume, the spacecraft power system and the surrounding electrical plasma environment. A good first step in understanding the nature of the interactions lies in making the needed plume parameter measurements in the far field. All diagnostic measurements are performed inside a large vacuum system (12 m diameter by 18 m high) with a full scale arc jet and solar array panel in the required flight configuration geometry. Thus, necessary information regarding the plume plasma parameters in the far field is obtained. Measurements of the floating potential, the plasma potential, the electron temperature, number density, density distribution, debye length, and plasma frequency are obtained at various locations about the array (at vertical distances from the arc jet nozzle: 2.6, 2.7, 2.8, 3.2, 3.6, 4.0, 4.9, 5.0, 5.4, 5.75, and 6.14 m). Plasma diagnostic parameters are measured for both the floating and grounded configurations of the arc jet anode and array. Spectroscopic optical measurements are then acquired in close proximity to the nozzle, and contamination measurements are made in the vicinity of the array utilizing a mass spectrometer and two Quartz Crystal Microbalances (QCM's). Galofaro, Joel T. and Vayner, Boris V. and Hillard, G. Barry and Chornak, Michael T. Glenn Research Center NASA/TM-2005-213837, E-15207
Download or read book Pulsed Plasma Thruster Plume Characterization of Ion Species Using a Gridded Energy Analyzer written by Krystal Marie Parker and published by . This book was released on 2002 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Temperature Effects on Pulsed Plasma Thruster Plume Expansion written by Nikos A. Gatsonis and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation Or a Pulsed Plasma Thruster Plume Using a Quadruple Langmuir Probe Technique written by Jurg C. Zwahlen and published by . This book was released on 2003 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Thrust Mechanisms in a Water Fed Pulsed Plasma Thruster written by Carsten A. Scharlemann and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Analytic models predict the possibility of extending the range of performance parameters of Pulsed Plasma Thrusters (PPT) by using propellants other than the traditionally used Teflon. A theoretical and experimental effort was initiated at The Ohio State University to investigate the use of alternative propellants for PPT. Analytical and numerical calculations (MACH2) indeed indicate a significant broadening of the obtainable range of specific impulse and thrust-to-power ratios when alternative propellants such as lithium or water are utilized. Consequently, in an effort to investigate changes in physical phenomena and thruster performance experimentally, a hybrid thruster was designed and built, facilitating the use of alternatively water or Teflon. The thruster design includes a unique water propellant feed system, allowing the supply of the water propellant without detrimentally affecting the inherent simplicity of the PPT system. ii The thruster operation and performance was investigated by several different diagnostic methods, including current and voltage measurements, Langmuir probes, and magnetic field probes. Furthermore, impact pressure measurements in the plume of the thruster allowed new insight into the plume structure and the accurate evaluation of impulse bits. Employment of the diagnostic methods for Teflon and water propellant enabled the unambigous identification of propellant related effects such as reduced electron temperature and higher exhaust velocites in the case of water propellant. The electromagnetic nature of the water thruster was clearly identified. For 30 J discharge energy, the water thruster requires only 5% of the mass bit of a Teflon thruster to produce an impulse bit 30% of the magnitude of the Teflon thruster, suggesting greatly increased propellant efficiencies. In agreement with the plasma diagnostic results, a specific impulse for the water thruster of up to 8000 s and efficiencies of up to 16% were evaluated.
Download or read book Plasma Diagnostics in the Near Field Plume of a Hall Thruster written by Kai-Mei C. Fu and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pulsed Plasma Thruster Plumes written by Nikos A. Gatsonis and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Basic Research in Electric Propulsion Part I Pulsed Plasma Thruster Propellant Efficiency and Contamination Part II Arcjet Remote Plume Measurement and Hydrogen Density written by and published by . This book was released on 2002 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulsed Plasma Thrusters (PPT) have been the major technology under investigation for the Small Satellite Electric Propulsion Thruster Research program. Arcjet technology is also under investigation with Electric Propulsion Space Experiment Optical Signature experiments underway and Multiphoton Laser Induced Fluorescence Measurements of Ground State Atomic Hydrogen have been performed in an arcjet plume. At present PPTs are being tested in the laboratory environment with investigations under way to determine exact inefficiency mechanisms that can be corrected. This work has already identified previously unknown physical behavior in the PPT. The Electric Propulsion Space Experiment is a flight demonstration of a 30 kW ammonia arcjet propulsion system. Optical measurements of the arcjet plume were performed using on-board optical equipment ground observatories and other space platforms. Low power arcjet technology provided definitive work on atomic species plume concentrations in low power hydrogen arcjet plumes. This work applied a flame diagnostic Multiphoton Laser Induced Fluorescence to the excited-state plasma environment to investigate concentration levels of atomic ground-state hydrogen.
Download or read book Liquid Pulsed Plasma Thruster Plasma Plume Investigation and MR SAT Cold Gas Propulsion System Performance Analysis written by Jeremiah Daniel Hanna and published by . This book was released on 2017 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The plasma plume produced by a liquid pulsed plasma thruster is investigated using a Langmuir triple probe and a nude Faraday probe. The Langmuir triple probe failed to produce results which are suspected caused by the presence of ionic liquid in the plume resulting in shorting of the probe. The nude Faraday probe is able to record the ion current density which revealed a high level of inconsistency in the plasma plume. Ion current density recorded by the nude Faraday probe had a relative standard deviation of upwards of 100% of the mean value. Controlling the amount of propellant used during each pulse was extremely difficult. Investigating the plasma plume with more complex probes was not done due to the inconsistency measured by the nude Faraday probe and the expulsion of ionic liquid from the thruster which is highly corrosive to metals. Examining the historical thrust test data performed by the Missouri Satellite Research Team, a revised model with new assumptions was created and resulted in an improvement in accuracy to within 4.5%. The cold gas propulsion system developed over the years had undergone testing which resulted in measured thrust half of what was predicted. Developing a thrust prediction scheme that incorporates the effects of the solenoid control valve decreases the error to between 1-3% depending on temperature considerations. This thrust prediction scheme can be applied to the current design for the NanoSat 8 competition and results in an accurate prediction of thrust"--Abstract, page iii.
Download or read book Pulsed Plasma Thruster Contamination written by Roger M. Myers and published by . This book was released on 1996 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Emission Measurements of a Pulsed Plasma Thruster Plume written by and published by . This book was released on 1997 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The optical emission spectra of plasmas produced by a Teflon (polytetrafluoroethylene (PTFE)) solid propellant pulsed plasma thruster (XPPT-1) were measured and analyzed. A broad temporally and spatially integrated survey of the emission from 3500 to 7500 angstrom is reported. It is shown that in the PPT discharge energy range surveyed (15 to 45 joule), the species formed do not vary; that is, no new species are formed as the discharge energy is increased. Furthermore, relative line ratios do not vary significantly with energy, suggesting that the bulk thermodynamic properties of the discharge plasma may not be affected by changing the initial stored capacitor energy. A spatially integrated but time- resolved measurement was carried out which shows the single species emission as a function of PPT discharge time. The magnitude of the emission was found to track closely with the PPT current and depend on the discharge energy. Relative line emission intensities are used to determine the degree of excitation equilibrium and establish bounds on the plasma temperature. Spatially and temporally resolved images are used to estimate the plasma streaming velocity from time-of-flight and Doppler-shift techniques.
