Download or read book The 30 KW Ammonia Arcjet Technology written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-04 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The technical results are summarized of a 30 kW class ammonia propellant arcjet technology program. Evaluation of previous arcjet thruster performance, including materials analysis of used thruster components, led to the design of an arcjet with improved performance and thermal characteristics. Tests of the new engine demonstrated that engine performance is relatively insensitive to cathode tip geometry. Other data suggested a maximum sustainable arc length for a given thruster configuration, beyond which the arc may reconfigure in a destructive manner. A flow controller calibration error was identified. This error caused previously reported values of specific impulse and thrust efficiency to be 20 percent higher than the real values. Corrected arcjet performance data are given. Duration tests of 413 and 252 hours, and several tests 100 hours in duration, were performed. The cathode tip erosion rate increased with increasing arc current. Elimination of power source ripple did not affect cathode tip whisker growth. Results of arcjet modeling, diagnostic development and mission analyses are also discussed. The 30 kW ammonia arcjet may now be considered ready for development for a flight demonstration, but widespread application of 30 kW class arcjet will require improved efficiency and lifetime. Deininger, W. D. and Chopra, A. and Pivirotto, T. J. and Goodfellow, K. D. and Barnett, J. W. Jet Propulsion Laboratory NASA-CR-186850, NAS 1.26:186850, JPL-PUBL-90-4 NAS7-918; RTOP 644-11-X2...
Download or read book Performance and Long Duration Test of a 30 Kw Thermal Arcjet Engine written by T. J. Pivirotto and published by . This book was released on 1987 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this effort was to evaluate the lifetime and performance of a 30-kWe constricted arc ammonia arcjet. This engine was based on a design developed by Avco Corporation in 1963 that delivered 978 seconds of specific impulse with ammonia during a 50-hour test. After 573 hours of operation, a short circuit between the cathode and anode of JPL's thruster forced the life test to end. Throughout the 573-hour test, the thruster operated at 24.9 kWe, delivering 2.29 N (0.15 lbs) of thrust, 865 seconds of specific impulse, and 37% efficiency. Although the lifetime of JPL's thruster fell short of AFAL's original 1500-hour goal for the effort, the arcjet demonstrated a duration of over eleven times the lifetime of the 1963 Avco arcjet. Further, the demonstrated lifetime of 576 hours is adequate for many orbit raising missions. Keywords: Electric propulsion; Electrothermal arcjet, Space propulsion.
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 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 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Investigation of the Breakdown Voltage Characteristics of a 30 KW Class Ammonia Arcjet written by D. L. Tilley 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 An Investigation of the Breakdown Voltage Characteristics of a 30 KW Class Ammonia Arcjet written by and published by . This book was released on 1993 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this work was to identify methods to reduce the mean dynamic breakdown voltage (MDBV) of the ammonia propellant in the ESEX 26 kW arcjet. The approach to this objective was to establish a test matrix to investigate the influence of mass flow rate, electrode gap distance, cathode tip shape, and voltage ramp rate on the MDBV. Only the mass flow rate and voltage ramp rate were observed to significantly affect the MDBV; the MDBV was observed to rise as either of these parameters were increased. These test results provided the basis for the start circuit redesign for the ESEX flight experiment, and also represent an initial data base of breakdown characteristics in high power ammonia arcjets. The second objective of this work was to identify the mechanisms associated with propellant breakdown in an arcjet. Progress towards this objective includes the following. A framework for investigating breakdown mechanisms in an arcjet was established which provides explanations for the strong dependence of the MDBV on the voltage ramp rate, the mass flow rate, and other parameters. A combination of a model, the calculation of electric field contours inside of the arcjet, and SEM photographs of a cathode tip indicate that the projection model for enhance field emission cannot alone account for the mean dynamic breakdown voltages observed in the high power arcjet. This result suggests that dielectric surface layers on the cathode tip are responsible for the enhanced field emission required to explain the observed MDBVs.
Download or read book Microengineering Technology for Space Systems written by Henry Helvajian and published by AIAA. This book was released on 1997 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: A follow-on to Micro- and Nanotechnology for Space Systems, this second monograph in the series uses the more universal term microengineering to define the discipline and processes that lead to the development of an integrated and intelligent microinstrument. Microengineering Technology for Space Systems addresses specific issues concerning areas for ASIM application in current space systems, operation in the space environment, ultra-high-density packaging and nonsilicon materials-processing tools, and the feasibility of the nanosatellite concept.
Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1995-03 with total page 1048 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 with total page 1450 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enhancing Space Transportation the NASA Program to Develop Electric Propulsion written by and published by . This book was released on 1990 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 30th AIAA ASME SAE ASEE Joint Propulsion Conference written by and published by . This book was released on 1994 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electromagnetic Effects of the ESEX 26 KW Ammonia Arcjet on Normal Spacecraft Communications and Operations written by and published by . This book was released on 1999 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Arcjet thrusters employ an arc discharge to heat propellant which expands through a nozzle to produce thrust. Spacecraft designers who desire to exploit arcjet technology have expressed concern about interference from the electromagnetic environment produced by the thrusters. One of the four major interest areas of the ESEX program was to determine the electromagnetic effect of operating a 30 kW class arcjet upon normal spacecraft communications and operations. To accomplish this task, noise levels were recorded in four frequency bands (2, 4, 8, and 12 GHz) by two onboard antennas. The electromagnetic noise levels observed during all arcjet firings were indistinguishable from those observed during the baseline non-firing periods. Communication bit error rates were also measured during arcjet firings and comparison with non-firing BER data revealed that spacecraft command and control communications were not significantly affected by arcjet firings.
Download or read book 87 2000 87 2047 written by and published by . This book was released on 1987 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Signal written by and published by . This book was released on 1999 with total page 714 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Air Force Magazine written by and published by . This book was released on 1993-07 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrazine and Its Derivatives written by Eckart Walter Schmidt and published by John Wiley & Sons. This book was released on 2001-08-24 with total page 868 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new edition of the authoritative source on hydrazine chemistry In the past century, hydrazine, an important intermediate in the synthesis of countless chemicals with N-N bonds, has grown into a major industrial commodity with a wide range of uses. It is used as a fuel in rocket propulsion, as a boiler feedwater deoxygenating agent, and in the manufacture of foamed plastics, pharmaceuticals, and biodegradable pesticides and herbicides, to name just a few uses. Since the first edition of Hydrazine and Its Derivatives: Preparation, Properties, Applications was published in 1984, there has been considerable development in this field and many new aspects of hydrazine chemistry and applications have evolved. Offering an overview of hydrazines and their industrial applications, this book also provides a compilation of numerous references to the scientific and technical literature arranged in a systematic manner, allowing the reader to find the necessary information by accessing the pages either from the table of contents or the alphabetical subject index. Some other features of the significantly enlarged Second Edition include: Frequent "see also" cross-references/links to other relevant sections of the bookOver 8,400 references, most of which cover the period from 1980 to 1998 Extremely thorough, encyclopedia-style coverage of topics Information to aid in the design of environmentally benign, biodegradable pesticides and more energetic rocket propellants Background information on the adverse effects of pesticide residue in food Hydrazine and Its Derivatives: Preparation, Properties, Applications, Second Edition is the most comprehensive book ever published on hydrazines, and this new edition is indispensable reading material for chemists, toxicologists, environmentalists, propulsion engineers, materials engineers, and satellite builders.
Download or read book Papers Presented at the AIAA ASME SAE ASEE 25th Joint Propulsion Conference written by and published by . This book was released on 1989 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
