| Development Status of the Helicon Hall Thruster |
15-Sep-2009 |
9 pages |
| Authors:
Rafael A Martinez; W A Hoskins; Peter Y Peterson; Dean Massey; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
 | The development status of a two-stage Hall thruster, the Helicon Hall Thruster, is presented. The Helicon Hall Thruster combines the efficient ionization mechanism of a helicon source with the favorable plasma acceleration properties of a Hall thruster. Conventional Hall thrusters rely on direct current electron bombardment to ionize the flow in order to generate thrust. Electron bombardment typically results in an ionization cost that can be on the order of ... |
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| Hall Effect Thruster Ground Testing Challenges |
18-Aug-2009 |
23 pages |
| Authors:
Michael R Nakles; Hargus; William A Jr; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| This paper presents the challenges in the ground testing of Hall effect thrusters for plasma spacecraft propulsion applications. Hall effect thrusters by virtue of their high specific impulse can reduce spacecraft station-keeping propulsion mass by as much as an order of magnitude. However, testing and qualifying such plasma propulsion systems for use on spacecraft has a number of challenges. These challenges include the need for simulating the space environment, measuring ... |
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| An Overview of Advanced Concepts for Near-Space Systems |
30-Jun-2009 |
19 pages |
| Authors:
Marcus Young; Stephanie Keith; Anthony Pancotti; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A brief review of both near-term and far-term platforms proposed for near-space operations is given. The primary focus of the paper is, however, a review of potential advanced propulsion systems for such long-duration near-space platforms. The basic requirements for near-space propulsion systems are defined. Low Reynolds number propellers, the current workhorse, are used as a baseline for comparison. Two broad classifications are identified as potential sources of force in near ... |
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| A Review of High Thrust, High Delta-V Options for Microsatellite Missions |
25-Jun-2009 |
15 pages |
| Authors:
Andrew Ketsdever; David B Scharfe; ENGINEERING RESEARCH AND CONSULTING INC (ERC INC) EDWARDS AFB CA
|
| Microsatellites have been suggested as a means of enhancing a variety of proposed space missions, ranging from low-Earth-orbit to solar-system exploration. With improvements in propulsion technology geared toward microsatellites, the ultimate delta-V (deltaV) capabilities of some microsatellite systems are now in the range of several km/s, opening the doors to a variety of high deltaV, fast response scenarios. This paper provides a brief overview of propulsion technologies currently available for ... |
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| Characterizing the Exhaust Plume of the Three-Electrode Micro Pulsed Plasma Thrusters |
Mar-2009 |
115 pages |
| Authors:
Seo Myeongkyo; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Three-electrode micro-PPTs are a new version of two electrode micro-PPTs devices. Performance predictions and contamination expectations are essential characteristics needed by satellite designers. In order to focus on thruster specific impulse, thrust and efficiency, measuring the exhaust velocity or impulse bit and propellant consumption rate is essential. While this is not always possible to measure directly, focusing on the ejected mass from the PPT provides significant information allowing determination of ... |
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| Ferroelectric Plasma Thruster |
29 FEB 2008 |
10 pages |
| Authors:
Scott D. Kovaleski; Mark A. Kemp; MISSOURI UNIV-COLUMBIA
|
| The Ferroelectric Plasma Thruster (FEPT) has been developed as an electrostatic micropropulsion thruster for the smallest classes of spacecraft. The FEPT consists of a thin wafer of lithium niobate ferroelectric material, with a solid electrode on one side, and an electrode with an aperture on the other. When radiofrequency high voltage is applied between the electrodes, through the thickness of the crystal, a combination of triple point and piezoelectric effects ... |
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| Capillary Discharge Based Pulsed Plasma Thrusters (Preprint) |
20 SEP 2007 |
15 pages |
| Authors:
Jean-Luc Cambier; Marcus Young; Leonid Pekker; Anthony Pancotti; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Although pulsed plasma thrusters have significant experimental heritage over a range of power levels, more recently they are often described as attractive low-power thrusters due to their small dimensions, simplicity, and ability to provide high specific impulses at low power levels. This paper, however, discusses research into the potential application of an electrothermal capillary discharge as a pulsed plasma generator useful in high-power spacecraft propulsion. A 0D transient physical model ... |
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| Design of Energetic Ionic Liquids (Preprint) |
27 AUG 2007 |
8 pages |
| Authors:
Jerry A. Boatz; Hui Li; Mark S. Gordon; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| An essential need of the US Air Force is the discovery, development, and fielding of new, energetic materials for advanced chemical propulsion in space and missile applications. Some of the key factors driving the requirement for new chemical propellants include: (a) improved performance in terms of increased specific impulse and density, (b) reduced sensitivity to external stimuli such as impact, friction, shock, and electrostatic discharge, and (c) mitigation of environmental ... |
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| Investigation of Non-Conventional Bio-Derived Fuels for Hybrid Rocket Motors |
AUG 2007 |
144 pages |
| Authors:
Scott G. Putnam; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Non-conventional bio-derived fuels have been evaluated for use in hybrid rocket motors. Tests were conducted at combustion pressures in the range of 100 - 220 psig and thrust levels of 40 - 170 newtons. Beeswax was tested with oxygen as the oxidizer and showed a regression rate at least three times as high as traditional hybrid propellant combinations such as hydroxyl-terminated polybutadiene (HTPB) and liquid oxygen (LOX). This provides the ... |
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| Investigation of Advanced Propellants to Enable Single Stage to Orbit Launch Vehicles |
30 OCT 2006 |
91 pages |
| Authors:
Jason Mossman; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| Single-Stage-To-Orbit (SSTO) launch vehicles designs offer the promise of reduced complexity and cost compared to multi-stage vehicles, as only one stage need be developed, produced, and maintained. Despite well-funded development efforts, no SSTO vehicles have been fielded to date. Existing chemical rocket and vehicle technologies do not enable feasible SSTO designs. In the future, new propellants with advanced properties could enable SSTO launch vehicles. A parametric sizing study was conducted ... |
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| Measurements and Computations of Mass Flow and Momentum Flux through Short Tubes in Rarefied Gases |
08 SEP 2006 |
|
| Authors:
T. C. Lilly; S. F. Gimelshein; A. D. Ketsdever; G. N. Markelov; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
 | Gas flows through orifices and short tubes have been extensively studied from the 1960s through the 1980s for both fundamental and practical reasons. These flows are a basic and often important element of various modern gas driven instruments. Recent advances in micro- and nanoscale technologies have paved the way for a generation of miniaturized devices in various application areas, from clinical analyses to biochemical detection to aerospace propulsion. The latter ... |
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| Explosive Comparison Trials; Cast TNT and TNT Drill Dust |
OCT 2005 |
19 pages |
| Authors:
Kenneth J. Knox; Timothy J. Shelley; AIR FORCE RESEARCH LAB KIRTLAND AFB NMSPACE VEHICLES DIRECTORATE
|
| A series of six blast experiments was conducted to compare the blast environments produced by Cast TNT (military TNT Demolition Charge blocks) and by TNT Drill Dust, a by-product of reclaiming cast TNT from decommissioned military ordnance. Each experiment employed 50-lb net explosive weight of the test explosive, and the blast environment was compared with that predicted by the ConWep software tool for uncased TNT. The Cast TNT produced a ... |
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| Characterization of the Absorption Wave Produced by CO2 Laser Ablation of a Solid Propellant |
OCT 2005 |
39 pages |
| Authors:
Wolfgang O. Schall; Hans-Albert Eckel; Jochen Tegel; Frank Holzschuh; GERMAN AEROSPACE CENTER (DLR) STUTTGART (GERMANY) INST OF TECHNICAL PHYSICS
|
| A requirement for efficient pulsed laser propulsion from ground to LEO is the achievement of a specific impulse of up to 800 s at a jet efficiency of at least 50%. With CO2 laser radiation at pulse lengths in the range of 10 microseconds and polymers as propellant these numbers cannot be attained by classical laser ablation. Also, the blending of the polymers with various metal powders did not improve ... |
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| Development of a Nano-Impulse Balance for Micropropulsion Systems |
28 SEP 2005 |
13 pages |
| Authors:
Brian C. D'Souza; Andrew D. Ketsdever; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
|
| Several versions of a torsional impulse balance have been developed as a new diagnostic tool to study fundamental physical processes in micropropulsion systems. With respect to the transfer of momentum, direct measurements of the transient forces or total impulse delivered can lead to a better understanding and characterization of the efficiency of the thrust that is possible under different configurations. The impulse balance has been designed and tested with a ... |
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| Free Molecule Micro-Resistojet: Nanosatellite Propulsion |
28 SEP 2005 |
11 pages |
| Authors:
Rick H. Lee; Taylor C. Lilly; E. P. Muntz; Andrew D. Ketsdever; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
|
| Constellations and platoons of small satellites can offer an assortment of benefits over larger, single function spacecraft. The strict mass, volume, and power limitations of small satellites will require unique micro-technologies to help develop efficient propulsion systems for maneuvering. The Free Molecule Micro-Resistojet (FMMR) has been analyzed and tested in this study to determine its applicability for an upcoming Texas A&M (TAM) nanosatellite mission. The nanosatellite mission will demonstrate the ... |
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| High Power Electric Propulsion System for NEP (systemes propulsifs electriques de forte puissance pour propulsion nucleo-electrique) |
13 JUL 2005 |
15 pages |
| Authors:
Christophe R. Koppel; Olivier Duchemin; Dominique Valentian; SNECMA MOTEURS VERNON (FRANCE) MOTEURS SPATIAUX DIV
|
| Recent US initiatives in Nuclear Propulsion lend themselves naturally to raising the question of the assessment of various options and particularly to propose the High Power Electric Propulsion Subsystem (HPEPS) for the Nuclear Electric Propulsion (NEP). The purpose of this paper is to present the guidelines for the HPEPS with respect to the mission to Mars, for automatic probes as well as for manned missions. Among the various options, the ... |
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| Experimental and Numerical Modeling of Rarefied Gas Flows Through Orifices and Short Tubes |
13 JUL 2005 |
8 pages |
| Authors:
S. F. Gimelshein; G. N. Markelov; T. C. Lilly; N. P. Selden; A. D. Ketsdever; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES
|
| Flow through circular orifices with thickness-to-diameter ratios varying from 0.015 to 1.2 is studied experimentally and numerically with kinetic and continuum approaches. Helium and nitrogen gases are used in the range of Reynolds numbers from 0.02 to over 700. Good agreement between experimental and numerical results is observed for mass flow and thrust corrected for the experimental facility background pressure. For thick-to-thin orifice ratios of mass flow and thrust vs ... |
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| Development of a Thrust Stand Micro-Balance to Assess Micropropulsion Performance |
JUN 2005 |
6 pages |
| Authors:
Anthony P. Pancotti; Taylor Lilly; Andrew D. Ketsdever; Victor Aguero; Paul R. Schwoebel; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| As proposed spacecraft and their associated thrusters have become smaller, technology has been developed to meet the demand for performance measurements for the extremely low force levels produced. For such thrusters, it is also desirable to measure the mass changes resulting from the utilization of propellant associated with either the steady state thrust or transient impulses. A thrust stand and novel data analysis method is presented to make both thrust ... |
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| Plume Expansion and Ionization in a Micro Laser Plasma Thruster |
JUN 2005 |
14 pages |
| Authors:
Michael P. Reilly; George H. Miley; William A. Hargus Jr; ILLINOIS UNIV AT URBANA
|
| Ion density measurements have been performed on the plasma generated by an ablative diode laser thruster using a negatively biased flat plate probe. The biased probe data was coupled with measurement of the ablation crater through use of a scanning electron microscope (SEM). The SEM was used to analyze the post-pulse ablation spots to determine the volume of fuel ablated. The micro-laser plasma thruster (micro-LPT) discussed here ablates a target ... |
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| Mass Spectrometric Analysis of Colloid Thruster Ion Emission from Selected Propellants |
JUN 2005 |
10 pages |
| Authors:
Yu-Hui Chiu; B. L. Austin; Rainer A. Dressler; Dale J. Levandier; P. T. Murray; P. Lozano; M. M. Sanchez Schatz; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Retarding potential, time-of-flight (TOF), and quadrupole mass spectrometric methods are applied to study the charged species emitted from a colloid thruster operated in a cone-jet mode at high-specific-impulse operating conditions. Measurements are conducted for two propellants, a 28.4 wt% NaI/formamide electrolyte solution and the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]). When operated at a volume flow rate of 2-6 x 10(to the minus 14th power) m3/s and a positive polarity, the ... |
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| Kinetics of Thermal Decomposition of Aluminum Hydride: I-non-Isothermal Decomposition Under Vacuum and in Inert Atmosphere (Argon) |
06 MAY 2005 |
13 pages |
| Authors:
I. M. Ismail; T. Hawkins; AIR FORCE RESEARCH LAB EDWARDS AFB CA
|
| Recently, interest in alane (aluminum hydride) has been renewed as a rocket propulsion ingredient due to improvements in its manufacturing process and an increase in thermal stability. When alane is added to solid propellant formulations, rocket performance is enhanced and the specific impulse increases. Preliminary work was performed at AFRL on the characterization and evaluation of two alane samples. Decomposition kinetics have been determined from gravimetric TGA data and volumetric ... |
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| Structural Isomers of bis(pentazolyl)iron(II): A Theoretical Study |
22 APR 2005 |
27 pages |
| Authors:
Jerry A. Boatz; Karl Christe; Ashwani Vij; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| The High Energy Density Materials (HEDM) Program objectives are: Identifying and developing advanced chemical propellants for rocket propulsion applications; specific impulse (Isp) is the major metric of a propellant's performance; density can also be a significant contributor. |
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| Shock User's Manual Version 1.0 |
APR 2005 |
24 pages |
| Authors:
Philip Wager; NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA
|
| SHOCK is a blast load analysis program, which will calculate the impulse and pressure on all or part of a blast surface, which is bounded by 1 to 4 reflecting surfaces. SHOCK will read input from a program data file or a Blast Library Database. The input can also be entered interactively. The required input is the length and width of the blast surface, the number and location of the ... |
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| Nuclear Thermal Rocket Propulsion Systems |
18 MAR 2005 |
17 pages |
| Authors:
Timothy J. Lawrence; AIR FORCE ACADEMY COLORADO SPRINGS CO DEPT OF ASTRONAUTICS
|
| Ideas for using nuclear energy for space propulsion began shortly after the first controlled nuclear chain reaction in 1942. Starting in the late 1940s, several development programs were pursued by the United States Air Force, the Atomic Energy Commission (now the US Department of Energy), and the National Aeronautics and Space Administration. Some of the systems developed from these programs are still in use today. To use nuclear power for ... |
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| Monte Carlo Simulation of a Rarefied Multiphase Plume Flow |
20 DEC 2004 |
5 pages |
| Authors:
Jonathan Burt; Iain D. Boyd; MICHIGAN UNIV ANN ARBOR DEPT OF AEROSPACE ENGINEERING
|
| Exhaust flows from solid propellant rockets are characterized by a number of complex and often overlooked phenomena which should be considered for accurate numerical modeling. In a typical solid rocket motor (SRM), a 10 to 20% mass fraction of aluminum powder is used to reduce combustion instabilities and increase specific impulse. Within the combustion chamber, this aluminum content undergoes a complicated process of melting, heretogenous combustion, evaporation, agglomeration, and breakup. ... |
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| Computationally Based Design and Screening of Hypergolic Multiamines |
DEC 2004 |
9 pages |
| Authors:
Michael J. McQuaid; William H. Stevenson; Darren M. Thompson; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Seeking to identify structural features of saturated, (all) tertiary, alkyl multiamines (STAMs) that correlate with hypergolic ignition delays, conformers of STAMS whose ignition delays have been measured were established through density functional theory-based calculations. Examined from the standpoint of lone pair/(C-N and C-C) bond orientations, a correlation is suggested. Conformers of 1,3-dimethylimidizolidine (DMIZ), a notional hypergol whose synthesis and testing was originally recommended for other reasons, were therefore characterized. On ... |
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| Experimental and Numerical Determination of Micropropulsion Device Efficiencies at Low Reynolds Numbers |
OCT 2004 |
47 pages |
| Authors:
Andrew D. Ketsdever; Michael T. Clabough; Sergey F. Gimelshein; Alina Alexeenko; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| The need for low thrust propulsion systems for maneuvers on micro- and nano-spacecraft is growing. Low thrust characteristics generally lead to low Reynolds number flows from propulsive devices that utilize nozzle expansions. Low Reynolds number flows of helium and nitrogen through a small conical nozzle and a thin-walled orifice have been investigated both numerically, using the Direct Simulation Monte Carlo technique, and experimentally, using a nano-Newton thrust stand. For throat ... |
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| Experimental and Numerical Determination of Micropropulsion Device Efficiencies at Low Reynolds Numbers |
SEP 2004 |
47 pages |
| Authors:
Andrew D. Ketsdever; Michael T. Clabough; Sergey F. Gimelshein; Alina Alexeenko; CALIFORNIA UNIV LOS ANGELES DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
|
| The need for low thrust propulsion systems for maneuvers on micro- and nano-spacecraft is growing. Low thrust characteristics generally lead to low Reynolds number flows from propulsive devices that utilize nozzle expansions. Low Reynolds number flows of helium and nitrogen through a small conical nozzle and a thin-walled orifice have been investigated both numerically, using the Direct Simulation Monte Carlo technique, and experimentally, using a nano-Newton thrust stand. For throat ... |
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| Experimental and Numerical Determination of Micropropulsion Device Efficiencies at Low Reynolds Numbers |
SEP 2004 |
47 pages |
| Authors:
Andrew D. Ketsdever; Michael T. Clabough; Sergey F. Gimelshein; Alina Alexeenko; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| The need for low thrust propulsion systems for maneuvers on micro- and nano-spacecraft is growing. Low thrust characteristics generally lead to low Reynolds number flows from propulsive devices that utilize nozzle expansions. Low Reynolds number flows of helium and nitrogen through a small conical nozzle and a thin-walled orifice have been investigated both numerically, using the Direct Simulation Monte Carlo technique, and experimentally, using a nano-Newton thrust stand. For throat ... |
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| "High-Power Hall Devices: Status and Current Challenges" |
25 JUN 2004 |
15 pages |
| Authors:
Alexander V. Semenkin; V. Kim; D. Manzella; V. Murashko; S. Tverdokhlebov; TSNIIMASH KOROLEV (RUSSIA)
|
| Consideration of the high power electric propulsion (EP) orbit transfer vehicles, interplanetary robotic and manned missions from one side and successful application of Hall thrusters onboard of numerous GEO satellites (Russian EXPRESS and YAMAL series), European scientific mission SMART-I on the other side stimulate interest to high power Hall devices, suitable for the future applications. Current experience for the Hall flight thrusters is limited by 1-kW-class of propulsion systems. At ... |
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| Descriptions of Hydrogen-Oxygen Chemical Kinetics for Chemical Propulsion |
22 JUN 2004 |
13 pages |
| Authors:
Forman A. Williams; CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF THE AEROSPACE AND MECHANICAL ENGINEERING SCIENCES
|
| There are many propulsion applications for which hydrogen and oxygen are attractive as fuel and oxidizer. These include liquid-propellant rocket motors with high specific impulse, air-breathing ramjets with supersonic combustion and certain types of pulse-detonation engines. Detailed knowledge of the chemical kinetics of combustion of hydrogen and oxygen is needed for rational design of combustors for such applications. Since there are only twenty-some steps in hydrogen-oxygen combustion chemistry, it is ... |
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| Design of Injectors for Self-Sustaining of Combustion Chambers Acoustic Stability |
22 JUN 2004 |
25 pages |
| Authors:
Vladimir Bazarov; MOSCOW INST OF AVIATION TECHNOLOGY (USSR)
|
| Comparative analysis of the injector development history in order to eliminate acoustic instability in combustion chambers of LOX/kerosene big thrust engines both of gas generator and staged combustion cycle such as F-1, RD-170 and some experimental engines is presented in the Paper. It was studied what stationary and dynamic parameters of injector elements and the injector assembly as a whole were changed during such a development and what kind of ... |
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| Isomer Energy Source for Space Propulsion Systems |
MAR 2004 |
136 pages |
| Authors:
Benjamin L. Johnson; ARMY WAR COLL CARLISLE BARRACKS PA
|
| Presented in this work are the results of an investigation of alternative means for powering spacecraft and launch vehicles with energy sources other than chemical combustion. Nuclear thermal propulsion and the energy release of a nuclear spin isomer present potential for increased rocket performance with compact, high-energy fuel sources replacing the combustion engines of the Delta IV-H 1st and 2nd stage vehicles. Analysis of historical fission designs along with the ... |
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| Program Research and Development Announcement - PRDA 04-01-PKT: integrated High Payoff Rocket Propulsion Technology XI (IHPRPT) |
13 FEB 2004 |
36 pages |
| Authors:
Frank Gulczinski; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| The Air Force Research Laboratory, Propulsion Directorate, AFRL/PR- West, Edwards AFB, CA is soliciting unclassified technical and price proposals for the effort described in Section A below. This announcement provides a complete description of the topic, the government projected funding profile and the technology areas to which the topic belongs. Proposals should be addressed to the Contracting POC and Technical POC stated in the Preface with the appropriate markings. This ... |
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| Establishment of a Hall Thruster Cluster |
FEB 2004 |
23 pages |
| Authors:
Alec D. Gallimore; MICHIGAN UNIV REGENTS ANN ARBOR DIV OFRESEARCH DEVELOPMENT AND ADMINISTRATION
|
| DURIP funds were used to develop a Hall thruster cluster test facility centered around the University of Michigan Large Vacuum Test Facility and a 2x2 cluster of BUSEK 600 W BHT-600 Hall thrusters. This capability will facilitate our three-year program to address the issue of high-power CDT operation and to provide insight on how chamber effects influence CDT engine/ cluster characteristics. |
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| Introduction to Solid Rocket Propulsion |
JAN 2004 |
|
| Authors:
P. Kuentzmann; OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AEROSPATIALES CHATILLION CEDEX (FRANCE)
|
| The objective of this paper is to present the fundamentals of solid rocket motor (SRM) propulsion. The following topics are covered: the history of SRMs; the basic components of an SRM; the efficiency of an SRM as defined by specific impulse; the characteristics of SRM operation as established by global conservation laws; transformation of the solid propellant to combustion products, which results in changes in pressure and thrust; aspects of ... |
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| Analysis of Scramjet with MHD Bypass |
OCT 2003 |
6 pages |
| Authors:
E. G. Sheikin; A. L. Kuranov; HYPERSONIC SYSTEMS RESEARCH INST SAINT PETERSBURG (RUSSIA)
|
| The propositions to use the MHD systems to control flow in a scramjet channel were put forward in development of the "M AJAX" concept. The paper 1, in which the basic principles for the MHD control in a scramjet were described for the first time in detail, was published in 1998. The main emphasis in the paper was put on analyzing the scramjet scheme with the control system composed of ... |
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| Thermodynamic Limitations on Energy Conversion in Laser Propulsion |
21 AUG 2003 |
24 pages |
| Authors:
C. W. Larson; F. B. Mead Jr.; S. D. Knecht; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Outline: Comparison of Constant Momentum Mission and Constant Specific Impulse Mission; Efficiency of conversion of laser energy to propellant kinetic energy; Upper limit to conversion of laser energy to jet kinetic energy from energy conservation and definitions; Comparing momentum quantities to energy quantities. The "Phi Factor" and velocity distributions in propellant jet. Phi values for delta function, Maxwellian, Gaussian, Chunks and gas, supersonic expansion, etc.; Upper limits to performance based ... |
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| Thermodynamic Limitations on Energy Conversion in Laser Propulsion |
21 AUG 2003 |
12 pages |
| Authors:
C. W. Larson; F. B. Mead Jr.; S. D. Knecht; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| We show that perfect propulsion requires a constant momentum mission, as a consequence of Newton's second law. Perfect propulsion occurs when the velocity of the propelled mass in the inertial frame of reference matches the velocity of the propellant jet in the rocket frame of reference. We compare constant momentum to constant specific impulse propulsion, which, for a given specification of the mission delta V, has an optimum specific impulse ... |
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| High Thrust to Weight Bipropellant Reentry Vehicle Thrust Vector Control Thru Micro-Miniaturization |
23 JUL 2003 |
38 pages |
| Authors:
Bill Figueiredo; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| These briefing charts represent a speech given by the author at the AIAA Joint Propulsion Conference held in Huntsville, Alabama, on 20-23 2003. The speech covered the following topics: the high thrust-to-weight ratios achievable through micro-miniaturization; the two candidate microthrusters that were investigated in this study (the MIT MEMS gas turbine bipropellant engine and the AFRL micronozzle); issues that diminish performance at reduced rocket engine lengths; effects of air drag ... |
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| Ion Energy Diagnostics in the Far-Field Plume of a High-Specific Impulse Hall Thruster |
30 JUN 2003 |
13 pages |
| Authors:
Richard R. Hofer; James M. Haas; Alec D. Gallimore; AIR FORCE RESEARCH LAB EDWARDS AFB CA
|
| Retarding potential analyzer and cylindrical Langmuir probe measurements were taken on the laboratory model NASA-173Mv2 to improve understanding of the physical processes affecting Hall thruster performance at high specific impulse. A retarding potential analyzer was used to measure the ion voltage distribution at voltages of 300-800 V. A cylindrical Langmuir probe was also used to obtain the local plasma potential so that the true ion voltage was obtained. The goal ... |
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| Polymers Used as Fuel for Laser Plasma Thrusters in Small Satellites |
30 APR 2003 |
50 pages |
| Authors:
Thomas Lippert; PAUL SCHERRER INST VILLIGEN (SWITZERLAND)
|
| This report results from a contract tasking Paul Scherrer Institut as follows: The contractor will investigate those properties of promising polymers which influence the performance of Laser Plasma Thrusters LPTs). Preliminary data show that the properties of the ablated polymer have a strong effect on the achievable specific impulse. Among the issues to be investigated are choice of substrate and adhesion of the polymer to the substrate influence of dopants ... |
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| Propulsion Technologies for Microsatellite Missions |
11 APR 2003 |
3 pages |
| Authors:
Daron Bromaghim; James Singleton; Stewart Bushman; Ron Spores; Lee Johnson; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Many near, to mid-term satellite missions have been identified for 200 kg class spacecraft. For many of these applications, significant delta-v capability is desired in order to perform orbit transfer, on-orbit repositioning and formation flying. Several of these systems are in advanced engineering development and could be ready to support flight opportunities as early as summer 2004. A 200 W Hall Effect Thruster (RET) system is being developed to satisfy ... |
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| A Colloid Engine Accelerator Concept Update |
16 JAN 2003 |
10 pages |
| Authors:
D. Kirtley; J. M. Fife; ENGINEERING RESEARCH AND CONSULTING INC(ERC INC) EDWARDS AFB CA
|
| A concept for a colloid engine with an electrodynamic linear accelerator is described. The charged particle source is a standard colloid engine with an extractor voltage that has an AC component Downstream of the extractor, a series of accelerator gates are biased alternately with an AC voltage such that the charged droplets tend to remain in regions with positive electric fields. Since the droplet speed varies with their position in ... |
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| Hall Thruster for Small, Low Power Satellites |
03 JAN 2003 |
5 pages |
| Authors:
William A. Hargus Jr.; Deborah Spotts; BUSEK CO INC NATICK MA
|
| The Air Force has the stated goal of gaining and retaining space dominance to protect US interests in all parts of the world. This will require large numbers of new satellites with uninterrupted, all weather coverage of the Earth's surface. To provide these capabilities at reasonable cost, new propulsion technologies, which utilize fuel more efficiently, are being developed. These propulsion technologies use electrical energy to accelerate plumes of ions and ... |
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| Laser Propulsion and the Constant Momentum Mission |
2003 |
13 pages |
| Authors:
C. W. Larson; Franklin B. Mead Jr.; Sean D. Knecht; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| We show that perfect propulsion requires a constant momentum mission, as a consequence of Newton's second law. Perfect propulsion occurs when the velocity of the propelled mass in the inertial frame of reference matches the velocity of the propellant jet. in the rocket frame of reference. We compare constant momentum to constant specific impulse propulsion, which, for a given specification of the mission delta V' has an optimum specific impulse ... |
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| Pulse Combustion Rockets for Space Propulsion Applications |
20 DEC 2002 |
13 pages |
| Authors:
Edward B. Coy; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
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| Pulse combustion propulsion devices are currently being considered as alternatives to conventional constant-pressure engines. Potential advantages include reduction or elimination of pumps and/or compressors, and improved Isp for a given feed system supply pressure. In this paper a model is presented for a monopropellant-fueled, constant-volume, pulse combustor which includes finite- rate processes. A zero-dimensional model is used for the combustion chamber and a one-dimensional, quasi-steady approximation is used for the ... |
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| Feasibility of SCRAMJET Technology for an Intermediate Propulsive Stage of an Expendable Launch Vehicle |
SEP 2002 |
119 pages |
| Authors:
Michael D. Schafer; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The single largest contributor to the cost of pulling objects into space is that of the launch portion. The currently available chemical rockets are only capable of specific impulse (Isp) values on the average of 300-350 seconds, with a maximum of 450 seconds. In order to improve the performance of the current families of launch vehicles, it is necessary to increase the performance of the rocket motors, and conversely the ... |
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| 'Green' Propulsion - A US Air Force Perspective* |
AUG 2002 |
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| Authors:
Tom W. Hawkins; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
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| Recent U.S. Air Force programs are aiming to develop reduced toxicity propellants. These programs focused on both solid and liquid propellant systems. In solid propulsion, investigation was performed for alternatives to ammonium perchlorate-based, space launch propellant. This was principally conducted under the auspices of the Strategic Environmental Research and Development Program (SERDP). This program was recently successfully concluded with a finding that green', ammonium nitrate-based propellant could be produced with ... |
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| Micro Laser Plasma Thrusters for Small Satellites |
AUG 2002 |
76 pages |
| Authors:
Claude R. Phipps; PHOTONIC ASSOCIATES SANTA FE NM
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| We developed and tested a preprototype micro laser plasma thruster (micro-LPT). This is a new departure in sub-kilogram micropropulsion modules, which we believe can compare favorably with the micro-PPT in total impulse/dry mass and thrust/power ratios. A lens focuses the light output of a group of fiber-coupled diode lasers onto a special ablatant tape. The tape is composed of a transparent supporting layer through which the light passes without perforating ... |
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Reports by Keyword(s)
SPECIFIC IMPULSE
