Download or read book Contamination Control and Plume Assessment of Low Energy Thrusters written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-12-29 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Potential contamination of a spacecraft cryogenic surface by a xenon (Xe) ion generator was evaluated. The analysis involves the description of the plume exhausted from the generator with its relative component fluxes on the spacecraft surfaces, and verification of the conditions for condensation, adsorption, and sputtering at those locations. The data describing the plume fluxes and their effects on surfaces were obtained from two sources: the tests carried out with the Xe generator in a small vacuum chamber to indicate deposits and sputter on monitor slides; and the extensive tests with a mercury (Hg) ion thruster in a large vacuum chamber. The Hg thruster tests provided data on the neutrals, on low-energy ion fluxes, on high-energy ion fluxes, and on sputtered materials at several locations within the plume. Scialdone, John J. Goddard Space Flight Center NASA-TM-104585, 93E01024, NAS 1.15:104585 ...
Download or read book Contamination Control and Plume Assessment of Low energy Thrusters written by John J. Scialdone and published by . This book was released on 1993 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Contamination Control and Plume Assessment of Low energy Thusters written by John J. Scialdone and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 1038 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hall Effect Thruster Plume Contamination and Erosion Study written by Donald A. Jaworske and published by . This book was released on 2000 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the Hall effect thruster plume contamination and erosion study was to evaluate the impact of a xenon ion plume on various samples placed in the vicinity of a Hall effect thruster for a continuous 100 hour exposure. NASA Glenn Research Center was responsible for the pre- and post-test evaluation of three sample types placed around the thruster: solar cell cover glass, RTV silicone, and Kapton(R). Mass and profilometer, were used to identify the degree of deposition and/or erosion on the solar cell cover glass, RTV silicone, and Kapton samples. Transmittance, reflectance, solar absorptance, and room temperature emittance were used to identify the degree of performance degradation of the solar cell cover glass samples alone. Auger spectroscopy was used to identify the chemical constituents found on the surface of the exposed solar cell cover glass samples. Chemical analysis indicated some boron nitride contamination on the samples, from boron nitride insulators used in the body of the thruster. However, erosion outweighted contamination. All samples exhibited some degree of erosion. with the most erosion occurring near the centerline of the plume and the least occurring at the +/- 90 deg positions. For the solar cell cover glass samples, erosion progressed through the antireflective coating and into the microsheet glass itself. Erosion occurred in the solar cell cover glass, RTV silicone and Kapton(R) at different rates. All optical properties changed with the degree of erosion, with solar absorptance and room temperature emittance increasing with erosion. The transmittance of some samples decreased while the reflectance of some samples increased and others decreased. All results are consistent with an energetic plume of xenon ions serving as a source for erosion.
Download or read book Some Sources of Contaminants in the Shuttle Bay Measured with Temperature Controlled Quartz Crystal Microbalances TQCM written by and published by . This book was released on 1996 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 93 2575 93 2615 written by and published by . This book was released on 1992 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Minimizing Plume Contamination Production in Bipropellant Thrusters written by E. A. DeGaetano and published by . This book was released on 1984 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Under a 1-year funded by the International Telecommunication Satellite Organization, the Rocketdyne Division of Rockwell International designed, fabricated, and tested a full-scale, advanced, storable, pressure-fed thruster for blowdown operation in the 1-lbf thrust range. The purpose of the program was a full-scale technology demonstration of an engine appropriate for use as a satellite station-keeping and attitude-control thruster. The primary features of the thruster are high performance, reduced plume contaminant production, and long life. Using nitrogen tetroxide and monomethyl-hydrazine, the thruster operates at 50 psia chamber pressure and produces a nominal vacuum specific impulse of 300 seconds with a 150:1 nozzle expansion ratio. The thruster chamber is made of beryllium and is radiation cooled. Reduction of the plume contaminant is accomplished by providing improved propellant evaporation for high combustion efficiency and by reduction of thruster propellant dribble volumes.
Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1994-12 with total page 950 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1996 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Electric Propulsion written by Dan M. Goebel and published by John Wiley & Sons. This book was released on 2008-12-22 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout most of the twentieth century, electric propulsion was considered the technology of the future. Now, the future has arrived. This important new book explains the fundamentals of electric propulsion for spacecraft and describes in detail the physics and characteristics of the two major electric thrusters in use today, ion and Hall thrusters. The authors provide an introduction to plasma physics in order to allow readers to understand the models and derivations used in determining electric thruster performance. They then go on to present detailed explanations of: Thruster principles Ion thruster plasma generators and accelerator grids Hollow cathodes Hall thrusters Ion and Hall thruster plumes Flight ion and Hall thrusters Based largely on research and development performed at the Jet Propulsion Laboratory (JPL) and complemented with scores of tables, figures, homework problems, and references, Fundamentals of Electric Propulsion: Ion and Hall Thrusters is an indispensable textbook for advanced undergraduate and graduate students who are preparing to enter the aerospace industry. It also serves as an equally valuable resource for professional engineers already at work in the field.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1994 with total page 1596 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1994 with total page 1374 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects and Control of Contamination From a Scaled MOL Translational Thruster in a Longitudinal Orientation written by and published by . This book was released on 1969 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: A test was conducted to determine the effects and control of contamination produced by a 1-lb scaled Manned Orbital Laboratory thruster. The test required firing the 1-lb translational thruster for 205 sec continuously and pulsing in its longitudinal position and determining the effects of contaminates from the thruster impinging on optical and thermal control surface test specimens located on a flat plate exposed to the thruster exhaust plume. The contamination ejected from the thruster in steady-state operation was much less than that of pulse-mode operation. Fences were used on the test plate to shield specimens from the thruster exhaust plume. In situ reflectance, emittance, and transmittance measurements were made on the optical and thermal control surface test specimens surfaces under vacuum conditions and at atmospheric pressure. Pretest and posttest laboratory measurements were made at atmospheric conditions. Contamination deposited on the plate was focused along and near the axis of the thruster. Contamination was ejected from the thruster at the startup of the engine in the steady-state operation. A 1.5-in. - high by 24-in. -long fence shielded specimens on the panel satisfactorily as opposed to a 0.75-in. -high fence. The in situ reflectance and transmittance measurements on the specimens at the simulated altitude were more realistic of the contamination encountered by the specimens from the thruster exhaust than the atmospherical posttest laboratory measurements.
Download or read book Aerospace America written by and published by . This book was released on 1992 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical System Contamination written by and published by . This book was released on 1996 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt:
