| Molecular Dynamics Modeling of Ionic Liquids in Electrospray Propulsion |
JUN 2010 |
126 pages |
| Authors:
Nanako Takahashi; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
 | Micro-propulsion has been studied for many years due to its applications in small-tomedium sized spacecraft for precise satellite attitude control. Electrospray thrusters are promising thrusters built upon the state of the art in micro-technology and with flexible performance in terms of their high efficiency and high specific impulse. One challenge is to investigate in detail the mechanism for ion emission to complement experimental results and understand better how emission occurs ... |
|
| New Decentralized Algorithms for Spacecraft Formation Control Based on a Cyclic Approach |
JUN 2010 |
233 pages |
| Authors:
Jaime L. Ramirez Riberos; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| When considering the formation control problem for large number of spacecraft, the advantages of implementing control approaches with a centralized coordination mechanism can be outpaced by the risks associated with having a primary vital control unit. Additionally, a centralized approach implies an inherent difficulty in gathering and broadcasting information from/to the overall system. Thus, there is a need to explore efficient decentralized control approaches. In this thesis a new approach ... |
|
| Trapped Electron Model 2 (TEM-2) |
25 Apr 2010 |
70 pages |
| Authors:
Paul O'Brien; Timothy B Guild; AEROSPACE CORP EL SEGUNDO CA
|
| We present a next-generation radiation specification for the electron radiation belts. The specification includes an empirical model of the statistical variation and spatiotemporal covariation of electron fluxes from 40 keV to 10 MeV in the inner and outer zones, as well as a dynamic full solar-cycle reanalysis, which provides a global snapshot of the electron fluxes every 6 hours from 1992 to 2008. The statistical model is derived from data ... |
|
| Kepler Mission Design, Realized Photometric Performance, and Early Science |
20 Apr 2010 |
9 pages |
| Authors:
David G Koch; William J Borucki; Gibor Basri; Natalie M Batalha; Timothy M Brown; Douglas Caldwell; Joergen Christensen-Dalsgaard; William D Cochran; Edna DeVore; Edward W Dunham; NAVAL OBSERVATORY FLAGSTAFF AZ
|
| The Kepler Mission, launched on 2009 March 6, was designed with the explicit capability to detect Earth-size planets in the habitable zone of solar-like stars using the transit photometry method. Results from just 43 days of data along with ground-based follow-up observations have identified five new transiting planets with measurements of their masses, radii, and orbital periods. Many aspects of stellar astrophysics also benefit from the unique, precise, extended, and ... |
|
| Software Technology Readiness Assessment. Defense Acquisition Guidance with Space Examples |
Apr 2010 |
83 pages |
| Authors:
Peter Hantos; AEROSPACE CORP EL SEGUNDO CA
|
|
| Kepler Planet-Detection Mission: Introduction and First Results |
19 Feb 2010 |
6 pages |
| Authors:
William J Borucki; David Koch; Gibor Basri; Natalie Batalha; Timothy Brown; Douglas Caldwell; John Caldwell; Joergen Christensen-Dalsgaard; William D Cochran; Edna DeVore; Edward W Dunham; Andrea K Dupree; III Gautier Thomas N; John C Geary; Ronald Gilliland; Alan Gould; Steve B Howell; Jon M Jenkins; Yoji Kondo; David W Latham; NAVAL OBSERVATORY FLAGSTAFF AZ
|
| The Kepler mission was designed to determine the frequency of Earth-sized planets in and near the habitable zone of Sun-like stars. The habitable zone is the region where planetary temperatures are suitable for water to exist on a planet's surface. During the first 6 weeks of observations, Kepler monitored 156,000 stars, and five new exoplanets with sizes between 0.37 and 1.6 Jupiter radii and orbital periods from 3.2 to 4.9 ... |
|
| Analysis of EAW and ReComm Communication Schemes for Hypersonic Flight: Status Report 1 |
01-Dec-2009 |
20 pages |
| Authors:
D V Rose; C Thoma; V Sotnikov; VOSS SCIENTIFIC LLC ALBUQUERQUE NM
|
| We summarize progress in our analysis of proposed communication schemes for hypersonic vehicles in flight. Investigations into the electron-acoustic wave (EAW) communication scheme have yielded a dispersion analysis indicating that EAW modes can be generated and propagate in the plasma layer [D. V. Rose et al., Voss Sci. Rep. No. VSL-0737, Nov. 2007]. These modes can be coupled to electromagnetic waves at the plasma layer boundary for the assumption of ... |
|
| Robust Adaptive Control Using a Filtering Action |
Sep-2009 |
120 pages |
| Authors:
Jia-Horng Yang; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This dissertation describes the design of an adaptive controller for single-input single-output (SISO) systems with guaranteed bounds on the transient response, and robustness with external disturbances and unmodeled dynamics. Developed from a current approach called L1 adaptive controller, we show that by adding two properly designed low pass filters at the input and at the estimator we can control the transient response and the sensitivity of the overall system to ... |
|
| 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 ... |
|
| Future Capabilities and Technologies for the Air Force in 2030. Executive Summary |
Jul-2009 |
61 pages |
| Authors:
David Blanks; John P Geis; Christopher J Kinnan; Ted Hailes; Harry A Foster; AIR WAR COLL MAXWELL AFB AL CENTER FOR STRATEGY AND TECHNOLOGY
|
| This second iteration of the Blue Horizons study, commissioned by the USAF chief of staff, provides ?a new look at the future.? Its original purpose was to develop a prioritized list of concepts and their key enabling technologies the USAF would need to maintain dominance in air, space, and cyberspace to the year 2030. In addition, the study examined whether the USAF could leverage a targeted investment today to position ... |
|
| Finite Set Control Transcription for Optimal Control Applications |
May-2009 |
260 pages |
| Authors:
Stuart A Stanton; TEXAS UNIV AT AUSTIN
|
| An enhanced method in optimization rooted in direct collocation is formulated to treat the finite set optimal control problem. This is motivated by applications in which a hybrid dynamical system is subject to ordinary differential continuity constraints, but control variables are contained within finite spaces. Resulting solutions display control discontinuities as variables switch between one feasible value to another. Solutions derived are characterized as optimal switching schedules between feasible control ... |
|
| Synthesis of Polyimides Produced from Novel High Temperature Polyhedral Oligomeric Silsesquioxane Dianilines |
26-Mar-2009 |
3 pages |
| Authors:
Vandana Vij; Joseph M Mabry; Timothy S Haddad; Gregory R Yandek; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Polyimides (PIs) are used extensively in a variety of applications such as circuit-printing films and semiconductor coatings in the microelectronics industry, spacecraft materials including solar arrays, thermal insulation blankets, and space inflatable structures, and in components in modern aircraft. PIs are well known for their thermal stability but are prone to long-term oxidative degradation and are notorious for having hydrothermal issues, especially when used in fiber-reinforced composites. A potential approach ... |
|
| Environmental Variation in Contamination Outgas Testing of a Composite Material |
15-Mar-2009 |
30 pages |
| Authors:
Keith R Olson; Kelsey A Folgner; AEROSPACE CORP EL SEGUNDO CA
|
| Molecular contamination degrades sensitive spacecraft surfaces and can adversely affect the useful life of a spacecraft. In order to accurately predict mission performance, a thorough understanding of the emission and condensation of potential spacecraft contaminants is necessary. Potential sources of contamination include composite materials that are often used for large structural components. The large mass of these composite structures can represent the largest outgassing source on a spacecraft. This report ... |
|
| Mission Planning for Close-Proximity Satellites |
Mar-2009 |
70 pages |
| Authors:
Barry R Witt; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Given an initial orbit and a set of other orbits of interest, the lowest change in velocity path between them is of high value. Software was developed to visualize the change in velocity required from a user defined window of burn to a user defined window of intercept. The time between burn and intercept is unrestricted. Multiple intercepts require searching an n! solution space, research then is focused on ways ... |
|
| An Energy-Based Thermodynamic Stabilization Framework for Hybrid Control Design of Large-Scale Aerospace Systems |
27-Feb-2009 |
42 pages |
| Authors:
Wassim M Haddad; GEORGIA INST OF TECH ATLANTA SCHOOL OF AEROSPACE ENGINEERING
|
| Controls research under this program has concentrated on the development of hybrid control, energy- and entropy based control, decentralized control, distributed control, cooperative control, and adaptive control. Specifically, a novel energy-based thermodynamic stabilization framework for hybrid control design of large-scale aerospace systems is developed. This framework provides a rigorous alternative to designing gain scheduled controllers for general nonlinear large-scale dynamical systems by constructing distributed and decentralized logic-based nonlinear controllers. |
|
| Atomistic Simulations of Hyperthermal Collisions Between Closed-Shell Species and Organic and Inorganic Surfaces |
Feb-2009 |
14 pages |
| Authors:
Diego Troya; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF CHEMISTRY
|
| This final report describes the efforts to develop computational- chemistry technology aimed at enabling simulation of gas/surface collisions of interest to the US Air Force that have been carried out under contract FA9550-06-1-0165. The report includes advances in three separate, but complementary lines of research that had the overarching goal of performing atomistic simulations of high-energy collisions between gases and surfaces with unprecedented levels of accuracy. These three lines are: ... |
|
| A Frequency Domain Approach to Pretest Analysis Model Correlation and Model Updating for the Mid-Frequency Range |
Feb-2009 |
21 pages |
| Authors:
Daniel C Kammer; Aaron Nimityongskul; WISCONSIN UNIV-MADISON BOARD OF REGENTS/RESEARCH SPONSORED PROGRAMS
|
| Large, high-performance space vehicles will require test-validated finite element models for accurate response predictions. The models of these precision spacecraft must be valid to a higher frequency range, referred to as the mid-frequency range, which is characterized by high modal density. The product of this research project is a complete finite element model validation procedure for the mid-frequency range, or any system with high modal density. The procedure includes sensor ... |
|
| Reduced Precision Redundancy Applied to Arithmetic Operations in Field Programmable Gate Arrays for Satellite Control and Sensor Systems |
Dec-2008 |
175 pages |
| Authors:
Margaret A Sullivan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis examines two problems in on-board computing for space vehicles and develops rules for applying Reduced Precision Redundancy (RPR) as a new method of fault tolerance in Field Programmable Gate Arrays against Single Event Effects due to radiation on orbit. RPR was discovered by Snodgrass in 2006 and was first demonstrated using the single-input CORDIC algorithm. This research applies RPR to elementary multiple-input arithmetic operations (addition, subtraction, multiplication, division) ... |
|
| An Autonomous Flight Safety System |
Nov 2008 |
12 pages |
| Authors:
James B Bull; Raymond J Lanzi; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WALLOPS ISLAND VA WALLOPS FLIGHT CENTER
|
| The Autonomous Flight Safety System (AFSS) being developed by NASA's Goddard Space Flight Center's Wallops Flight Facility and Kennedy Space Center has completed two successful developmental flights and is preparing for a third. AFSS has been demonstrated to be a viable architecture for implementation of a completely vehicle based system capable of protecting life and property in event of an errant vehicle by terminating the flight or initiating other actions. ... |
|
| Integration of the Coliseum Plasma Simulation Tool with the Charging Code, Nascap-2k (Preprint) |
06-Jul-2008 |
8 pages |
| Authors:
Lubos Brieda; Alex Barrie; Michael Gorrilla; Myron Mandell; Victoria Davis; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| This paper presents results from an effort to integrate the AFRL plasma modeling tool Coliseum with the SAIC/SEE, AFRL/VSB charging code Nascap-2k. Coliseum is used to compute the current collected by the test article at a fixed surface potential. Charging of the object is then computed by Nascap-2k and the new surface potential is exported to Coliseum. The process is iterated until surface potential reaches steady state. This approach is ... |
|
| Operationally Responsive Space (ORS) Architecture for the Year 2025 |
15-Jun-2008 |
109 pages |
| Authors:
K Hansen; M Widmann; B Hatcher; J Kacala; J Rayburn; J Turner; M Senn; S Ledoux; S Kennedy; J Carson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA SPACE SYSTEMS ACADEMIC GROUP
|
| The Unites States' first space systems programs were initially developed to meet the requirements of strategic users. Since the 1991 Gulf War there has been a growing dependence on the capabilities and support delivered by these programs to meet the requirements of nonstrategic users. The current National Security Space (NSS) architecture makes it rather difficult for all but critical strategic users to fully capitalize on the available assets. Timelines that ... |
|
| Spaceborne Fiber Optic Data Bus (SFODB) |
01-Jun-2008 |
5 pages |
| Authors:
J W Bretthauer; C H Chalfant; F J Orlando; E Rezek; M Sawyer; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GREENBELT MD GODDARD SPACE FLIGHT CENTER
|
| Spaceborne Fiber Optic Data Bus (SFODB) is an IEEE 1393 compliant, gigabit per second, fiber optic network specifically designed to support the real-time, on-board data handling requirements of remote sensing spacecraft. The network is fault tolerant, highly reliable, and capable of withstanding the rigors of launch and the harsh space environment. SFODB achieves this operational and environmental performance while maintaining the small size, light weight, and low power necessary for ... |
|
| Impact of the Boundary Layer on Pointing and Tracking in Airborne Free-Space Laser Communication Links |
JUN 2008 |
120 pages |
| Authors:
Ross A. Conrad; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| Free-space laser communication is a developing technology with enormous potential to revolutionize the way people communicate across the globe. Of specific interest are air-to-space lasercom links. Such a link experiences atmospheric scintillation, platform jitter, and boundary layer turbulence. This research investigated the tracking challenge using a focal plane array sensor with centroid and peak tracking algorithms. Also investigated was the use of a deformable mirror to recreate optical phase distortions ... |
|
| Thermal Conductivity and Speed of Sound Measurements of Liquid Hydrazine (N2H4) at 293.15K and 0.101 MPa to 2.068 MPa |
25 APR 2008 |
23 pages |
| Authors:
John D. DeSain; Brian B. Brady; AEROSPACE CORP EL SEGUNDO CA
|
| The thermal conductivity of liquid hydrazine was measured by the steady-state hot-wire method at 293.15K and 0.101 MPa. Eight pure organic liquids were used as reference liquids to calibrate the experimental apparatus. The current measurement is in agreement with one recent measurement. However, the current measurement disagrees with the most recent measurement, as well as several previous measurements and estimation methods. The thermal conductivity was determined to change very little ... |
|
| Contamination Study of Micro Pulsed Plasma Thruster |
MAR 2008 |
116 pages |
| Authors:
Ceylan Kesenek; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| Satellite designing trend is progressing towards building smaller satellites. Small satellites require micro propulsion devices for accurate control by the propulsion system. Micro-Pulsed Plasma Thrusters (PPTs) are highly reliable and simple micro propulsion systems that will offer attitude control, station keeping, constellation flying, and drag compensation for such satellites. As an unfortunate side effect, the plume induces contamination on spacecraft surfaces and may lead to significant problems with sensors and ... |
|
| Thermal Characterization of a Hall Effect Thruster |
MAR 2008 |
105 pages |
| Authors:
Alex M. Bohnert; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The thermal characteristics of a Hall thruster directly influence thruster and spacecraft design. High temperatures affect the magnetic coil capabilities and cause higher insulator erosion rates, influencing both thruster performance and lifetime. The Hall thruster transfers heat through both radiation and conduction, and the spacecraft must handle this additional thermal energy. An infrared camera provides a non-intrusive method to analyze the thermal characteristics of an operational Hall thruster. This thesis ... |
|
| 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 ... |
|
| Understanding Airpower: Bonfire of the Fallacies |
Jan-2008 |
42 pages |
| Authors:
Colin S Gray; READING UNIV (UNITED KINGDOM)
|
| This study rests upon two vital assumptions, both of them anathema to post-modern minds. First, it believes that historical truth can be found, or at least approached. Second, it believes in the utility of ambitious theory. The discussion here flatly rejects the proposition that history simply comprises competing fables told by historians with interests and attitudes. Similarly, it dismisses almost out-of-hand the belief that one theory is worth about as ... |
|
| Ionic Liquids as Hypergolic Fuels (Postprint) |
Jan-2008 |
3 pages |
| Authors:
Tommy Hawkins; Ghanshyam Vaghjiani; Michael Rosander; Steven Chambreau; Stefan Schneider; Gregory Drake; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| After seminal work presented a decade ago, ionic liquids (IL) have now received a lot of attention as energetic materials for propellant applications. In bipropellant rocket engines, it is desirable to achieve ignition by means of a hypergolic reaction and so to minimize system complexity. Hypergolic bipropellants are defined as fuel and oxidizer combinations that, upon contact, chemically react and release enough heat to spontaneously ignite, eliminating the need for ... |
|
| Guidelines and Metrics for Assessing Space System Cost Estimates |
2008 |
|
| Authors:
Bernard Fox; Kevin Brancato; Brien Alkire; RAND CORP SANTA MONICA CA
|
 | This handbook is designed to help analysts assess cost estimates of space systems. It assumes that the reader understands common cost analysis methodologies but has limited experience with space systems. Its objective is to give the analyst tasked with reviewing an estimate information to help accomplish the following tasks: Plan the review. Identify the key programmatic, technical, and cost data needed, along with suggested sources. Highlight common issues to investigate. ... |
|
| Micrometeoroid and Orbital Debris Environments for the International Space Station |
15 DEC 2007 |
12 pages |
| Authors:
T. E. Gallini; J. A. Hackwell; D. C. Marin; Michael Zambran; Glenn E. Peterson; David K. Lynch; AEROSPACE CORP EL SEGUNDO CA
|
| Baseline micrometeoroid and orbital debris fluence estimates for spacecraft in low Earth orbit (LEO) are provided. For these calculations, an orbit similar to that of the International Space Station (ISS) is used. |
|
| Phase Diversity Wavefront Sensing for Control of Space Based Adaptive Optics Systems |
DEC 2007 |
71 pages |
| Authors:
Richard J. Schgallis; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Phase Diversity Wavefront Sensing (PD WFS) is a wavefront reconstruction technique used in adaptive optics, which takes advantage of the curvature conjugating analog physical properties of a deformable mirror (MMDM or Bi-morph) such that the computational intensity required for correcting an aberrated wavefront, becomes simplified over traditional Shack-Hartmann WFS techniques. By looking at an image reflected off a deformable mirror by two cameras placed on either side of focus of ... |
|
| Space Particle Hazard Measurement and Modeling |
30 NOV 2007 |
46 pages |
| Authors:
James Metcalf; Jay Albert; Donald Brautigam; Gregory Ginet; Michael Golightly; Christine Knorring; Shu Lai; Edmund Murad; Shawn Young; AIR FORCE RESEARCH LAB HANSCOM AFB MA
|
| This report describes R&D to measure and model the near-earth space environment and the effects of the environment on spacecraft in orbit. Data from two Compact Environmental Anomaly Sensors (CEASE) were analyzed to derive flux spectra of energetic particles. Data from CEASE were also used to create maps of proton fluxes in the South Atlantic Anomaly at multiple altitudes between 400 and 1650 km. A new approach to modeling the ... |
|
| Tribochemistry of Multiply-Alkylated Cyclopentane Oils on DLC-Coated Thrust Bearings |
15 NOV 2007 |
28 pages |
| Authors:
Jeffrey R. Lince; Patricia A. Bertrand; AEROSPACE CORP EL SEGUNDO CA ENGINEERING AND TECHNOLOGY GROUP
|
| In contrast to typical DLC coatings, hydrogenated DLC (H-DLC) coatings exhibit extremely low friction in vacuum and dry atmospheres, suggesting their potential importance for spacecraft applications. We have conducted a study of H-DLC-coated steel thrust bearings, lubricated with a multiply-alkylated cyclopentane oil, either unformulated, or formulated with lead naphthenate or an aryl phosphate ester mixture. Data on uncoated steel thrust bearings were obtained for comparison. The surface chemistry of the ... |
|
| TOmographic Remote Observer of Ionospheric Disturbances |
15 NOV 2007 |
13 pages |
| Authors:
Charles Swenson; Matthew Carney; Jared Clements; Karl Burk; UTAH STATE UNIV LOGAN
|
| This document presents the final report for the USUSat III program funded by the Air Force Office of Scientific Research. The goal of this program has been to develop a next generation of engineers and scientists with skills in space systems. This objective was to be accomplished through a design and fabrication competition between university teams. The competing teams were all sponsored in the University Nanosatellite Program by the Air ... |
|
| The Lightcraft Technology Demonstration Program. Part 1 |
NOV 2007 |
304 pages |
| Authors:
Jr Mead Franklin B.; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Part I - The Lightcraft Technology Demonstration Program (LTD) is a report on the development of laser propulsion at the Air Force Research Laboratory (AFRL) between 1996 and 1999. The LTD Program was originally planned in five phases. Phase I, Lightcraft Concept Demonstration, was to demonstrate the feasibility of the basic concept. This phase ended in December 1998. Phase II, Lightcraft Vertical Launches to Extreme Altitudes, was a five-year effort ... |
|
| Self-Passivation of POSS-Kapton-Polyimides in the Presence of Atomic Oxygen (Preprint) |
29-Oct-2007 |
5 pages |
| Authors:
Vandana Vij; Gregory Yandek; Sandra J Tomczak; Michael E Wright; Andrew J Guenthner; Brian J Petteys; Timothy K Minton; Joseph M Mabry; Amy L Brunsvold; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Evidence for the formation of a protective silica layer on the surface of POSS-Kapton(Registered)-PIs upon exposure to AO was found in X-Ray Photoelectron Spectroscopy (XPS) studies of POSS-Kapton(R)-PIs flown on the Materials International Space Station Experiment (MISSE1), and in separate studies of POSS-Kapton(R)-PIs exposed to AO in a ground-based facility. To directly compare the effect of AO on Kapton H(R), SiO2 coated Kapton HN(R), and 8.75 weight % Si8O11 cage ... |
|
| Bandit: Technologies for Proximity Operations of Teams of Sub-10Kg Spacecraft |
16 OCT 2007 |
13 pages |
| Authors:
Michael A. Swartwout; WASHINGTON UNIV ST LOUIS MO DEPT OF SYSTEMS MECHANICAL AND AEROSPACE ENGINEERING
|
| This work was pursued as a supplement to an existing University Nanosat-4 activity (the Akoya/Bandit mission at Washington University). The objective of this work was to develop control theory for operating the 3-kg free-flying Bandit spacecraft, as expressed by two goals: improve the fidelity and performance of our 3DOF hardware testbed and 6DOF simulator; develop, test and evaluate two methods for autonomous multi-vehicle control (behavior-based and waypoint/autopilot) Control theory was ... |
|
| Review of Laser Lightcraft Propulsion System (Preprint) |
16 OCT 2007 |
13 pages |
| Authors:
Eric W. Davis; Jr Mead Franklin B.; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Laser-powered "Lightcraft" systems that deliver nano-satellites to LEO have been studied for the Air Force Research Laboratory (AFRL). The study was built on the extensive Lightcraft laser propulsion technology already developed by theoretical and experimental work by the AFRL's Propulsion Directorate at Edwards AFB, CA. Here we review the history and engineering-physics of the laser Lightcraft system and its propulsive performance. We will also review the effectiveness and cost of ... |
|
| 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 ... |
|
| Federal Research and Development Funding: FY2008 |
20 SEP 2007 |
|
| Authors:
Michael E. Davey; Christine M. Matthews; John D. Moteff; Daniel Morgan; Robert Esworthy; Wendy H. Schacht; Pamela W. Smith; Wayne A. Morrissey; LIBRARY OF CONGRESS WASHINGTON DC CONGRESSIONAL RESEARCH SERVICE
|
| The Bush Administration has requested $142.7 billion in federal research and development (R&D) funding for FY2008. As in the recent past, the FY2008 proposed increase over the FY2007 funding level is due to significant funding increases in the Department of Defense (DOD); the National Aeronautics and Space Administration's (NASA's) space vehicles development program; and the continuation of the American Competitiveness Initiative (ACI). The President initiated the ACI in FY2007 and ... |
|
| Future of Space Propulsion (Preprint) |
04 SEP 2007 |
29 pages |
| Authors:
John F. Remen; Glenn Liston; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A lot has happened in the area of space propulsion over the last 10 years prompting one to wonder, "Where are we going next?" This paper will first take a quick look back at history and from this perspective postulate the future directions for space propulsion. Topics to be addressed include spacelift and spacecraft propulsion. The future holds many great opportunities but just as many technical challenges. |
|
| Characterization of Graphite Lithium-Ion Cells |
SEP 2007 |
119 pages |
| Authors:
Steven D. Moseley; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis explores the characterization of graphite lithium-ion cells. A control procedure was performed to ensure any capacity loss or gain seen in tests was not the result of cell cycling. Vibration testing of the cells on all three axes to simulate the spacecraft launch environment showed a slight increase in capacity after vibration. Cell capacity was measured at two current rates at a variety of temperatures to obtain a ... |
|
| Tribochemistry and Wear Life Improvement in Liquid-Lubricated H-DLC-Coated Bearings |
25 JUL 2007 |
32 pages |
| Authors:
J. R. Lince; H. I. Kim; P. A. Bertrand; O. L. Eryilmaz; A. Erdemir; AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS
|
| In contrast to typical DLC coatings, hydrogenated DLC (H-DLC) coatings exhibit extremely low friction in vacuum and dry atmospheres, suggesting their potential importance for spacecraft applications. We have conducted a study of H-DLC coated steel thrust bearings, lubricated with a multiply-alkylated cyclopentane oil, either unformulated, or formulated wit lead naphthenate or an aryl phosphate ester mixture. Data on uncoated steel thrust bearings were obtained for comparison. The surface chemistry of ... |
|
| Dynamics of Hyperthermal Collisions of O(3P) with CO (Preprint) |
17 JUL 2007 |
59 pages |
| Authors:
Amy L. Brunsvold; Hari P. Upadhyaya; Jianming Zhang; Russell Cooper; Timothy K. Minton; Matthew Braunstein; James W. Duff; MONTANA STATE UNIV BOZEMAN DEPT OF CHEMISTRY AND BIOCHEMISTRY
|
| The dynamics of O(3P) + CO collisions at a hyperthermal collision energy of 83 kcal mol(-1) have been studied with a crossed molecular beams experiment and with quasiclassical trajectory calculations on computed potential energy surfaces. In the experiment, a rotatable mass spectrometer detector was used to monitor inelastically and reactively scattered products as a function of velocity and scattering angle. From these data, center-of-mass (c.m.) translational energy and angular distributions ... |
|
| Excitation of the Magnetospheric Cavity |
16 JUN 2007 |
44 pages |
| Authors:
Timothy F. Bell; Prajwal Kulkarni; STANFORD UNIV CA SPACE TELECOMMUNICATIONS AND RADIOSCIENCE LAB (STAR)
|
| Stanford University carried out a detailed study of the following topics: 1) the optimum orbit for exciting the magnetospheric cavity resonance by a space-based ELF/VLF transmitter, 2) the antenna type and configuration necessary to excite various cavity modes with the radiated ELF/VLF waves, 3) the effects of Landau damping on the ELF/VLFL waves within the cavity, 4) the effectiveness of the radiated ELF/VLF cavity waves in precipitating energetic radiation belt ... |
|
| Federal Research and Development Funding: FY2008 |
06 JUN 2007 |
|
| Authors:
Michael E. Davey; Christine M. Matthews; John D. Moteff; Daniel Morgan; Robert Esworthy; Wendy H. Schacht; Pamela W. Smith; Wayne A. Morrissey; LIBRARY OF CONGRESS WASHINGTON DC CONGRESSIONAL RESEARCH SERVICE
|
| The Bush Administration has requested $142.7 billion in federal research and development (R&D) funding for FY2008. As in the recent past, the FY2008 proposed increase over the FY2007 funding level is due to significant funding increases in the Department of Defense (DOD); the National Aeronautics and Space Administration's (NASA's) space vehicles development program; and the continuation of the American Competitiveness Initiative (ACI). The President initiated the ACI in FY2007 and ... |
|
| Advanced Integrated TPS and Non Equilibrium Chemistry Instrumentation |
01 JUN 2007 |
51 pages |
| Authors:
Monika Auweter-Kurtz; Markus Fertig; Georg Herdrich; Michael Winter; STUTTGART UNIV (GERMANY F R)
|
| Upon entering the atmosphere of celestial bodies, spacecraft encounter gases at velocities of more than 10 km/s, thereby being subjected to great heat loads. This makes it necessary to use high temperature thermal protection systems (TPS) to prevent the destruction of the space vehicle. The TPSs as well as the plasma environment during the entry have to be investigated by means of computational and ground facility simulations. The four plasma ... |
|
| Spacecraft Charging - Present Situation and Some Problems |
JUN 2007 |
11 pages |
| Authors:
Shu T. Lai; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| The geosynchronous environment is the most important region in the magnetosphere for spacecraft charging because the plasma temperature can be very high; the plasma density is sometimes very low, and most communications satellites are there. It is now well understood that, for a given surface material, there exists a critical plasma temperature above which spacecraft charging to negative potentials occurs. High energy (MeVs) electrons and ions penetrate into material to ... |
|
| Final Development, Testing, and Flight Preparation of the Rigidizable Get-Away-Special Experiment (RIGEX) |
JUN 2007 |
366 pages |
| Authors:
Zachary R. Miller; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| The purpose of this research is to support the final development of the Rigidizable Inflatable Get-Away-Special Experiment (RIGEX). The RIGEX program is an experimental initial step in developing large-scale rigidizable inflatable structures, which can be utilized in space applications. The primary intent of RIGEX is to verify and validate ground testing of inflation and rigidization methods for inflatable space structures against a zero-gravity space environment. This is performed by designing ... |
|
Reports by Keyword(s)
SPACECRAFT
