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Recent Publications and Patents by the Aerospace Technical Staff

Patents

W. F. Buell and B. Jaduszliwer, "Continuous Cold Atom Beam Atomic System," U.S. Patent No. 6,303,928, Oct. 2001.

A single-laser-beam magneto-optic trap is used to generate a slow, continuous, high-flux beam of atoms for use in a cold-atom clock. The highly stable device uses gradient magnetic fields and a single circularly polarized laser beam directed toward a right-angle conical mirror with an opening at the apex. The continuous cold-atom beam and a central portion of the incident laser beam exit through the opening along the axis of the cone. A collimating and deflecting laser provides transverse cooling of the atomic beam to bend, brighten, and separate it from the entrapping laser light, thereby reducing shifts in the operating frequency of the atomic clock. The continuous beam relaxes requirements on the local oscillator, which can be stringent for clocks using pulsed cold-atom streams.

D. J. Chang and P. R. Valenzuela, "Pressure Vessel Testing Fixture," U.S. Patent No. 6,253,599, July 2001.

This method for sealing a cylindrical composite tube improves pressure testing. The ends of the tube are inserted into fixtures having a vertically extending flange that slides inside the tube. A ferrule is placed around the outer wall of the tube, and a retaining ring is placed around the ferrule. Both the ferrule and retaining ring have mating slanted abutting surfaces. The retaining ring has an inner diameter slightly smaller than the outer diameter of the ferrule. As the retaining ring is clamped down upon the end fixtures, the slanted abutting surfaces slide against each other to apply a normal radial compression between the tube and flange and between the tube and ferrule. This compression generates a mechanical friction or shear force when the tube and end fitting are pulled apart longitudinally under high internal pressure during testing. The radial compression secures the tube in the fixture and also prevents leaks.

Z. H. Duron, "Wave Speed Bridge Damage Detection Method," U.S. Patent No. 6,257,064, July 2001.

This nondestructive method for testing the structural integrity of bridges and other large structures is based on the accurate characterization of an impact wave traveling through the bridge or structure. Accelerometers are placed at each end of a support girder, and a calibrated impact hammer is used to strike the girder at a specific location. For each impact location, a series of several data sets can be generated to ensure statistical accuracy with high coherence in results. Wave-speed estimates are based on measured arrival times and distances between impact and measurement locations. Large changes in a wave-speed index indicate a high probability of a structural change in the bridge, indicating possible damage. Standard computer and communications technologies are used to acquire and process the measured responses. The method can be used to determine distinct damage to a bridge caused by significant events or to track structural changes over time.

J. A. Gelbwachs, "Cloud Base Measurement Method," U.S. Patent No. 6,281,969, Aug. 2001.

This technique describes how an instrument positioned above a cloud can determine the altitude of the base of the cloud. The high-altitude or space-based lidar method is not restricted by cloud attenuation but relies on cloud porosity and diffuse reflections from land or water. First, a pulsed laser beam is sent through a clearing in the cloud toward the ground, where it is diffusely reflected or scattered. Some of the reflected laser light returns directly to the lidar system, and some of it strikes the base of the cloud. Some of the light that hits the cloud is reflected back to Earth, where it is again reflected diffusely toward the sky. Some of this light reaches the lidar system, which calculates the altitude of the cloud base by computing the time difference between the first and second returns.

L. K. Herman, C. M. Heatwole, G. M. Manke, B. T. Hamada, "Pseudo Gyro With Unmodeled Disturbance Torque Estimation," U.S. Patent No. 6,263,264, July 2001.

Using software processes, this pseudo gyro emulates the functions of a hardware gyro. Used in place of a traditional gyro, the instrument can increase the lifetime and reliability of a satellite system while reducing power requirements. Computations are based on the principle of conservation of momentum. By accounting for the momentum from external torques and the transfer of momentum between a satellite bus and its appendages and momentum-storage devices, the pseudo gyro calculates the angular velocity of the vehicular bus. Information concerning relative position and rate is taken from the attitude and appendage controllers and tachometers onboard the satellite.

R. P. Patera, "Space Vehicular Fly-By Guidance Method," U.S. Patent No. 6,302,354, Oct. 2001.

A fly-by guidance algorithm can be used to maneuver a space vehicle into a desired fly-by trajectory near another space vehicle or object. The guidance algorithm consists of a predictive phase and a modified proportional navigation phase. Using time data from an onboard clock and angular line-of-sight data from an onboard sensor, the predictive guidance phase maneuvers the space vehicle in preparation for the modified proportional navigation phase, during which the fly-by vehicle accelerates toward the object on an intercept course. The algorithm determines the precise time to terminate maneuvering to achieve the desired fly-by distance. The algorithm is well suited for monitoring and imaging of space vehicles and planetary objects.

E. J. Simburger, D. A. Hinkley, E. Y. Robinson, D. G. Gilmore, J. V. Osborn, "Power Sphere Nanosatellite," U.S. Patent No. 6,284,966, Sept. 2001.

A power source for a nanosatellite is formed from several flat polygonal solar panels connected by rotating hinges. The apparatus remains stowed until deployment, when it forms a sphere that encloses the payload. The solar-array panels are supported by an extending internal strut. The spherical shape provides attitude-insensitive solar energy collection as well as passive heat radiation.

E. J. Simburger, J. H. Matsumoto, T. W. Giants, A. Garcia III, F. R. Jeffrey, P. A. Gierow, "Integrated Solar Power Module," U.S. Patent No. 6,300,158, Oct. 2001.

A flexible 3-D printed circuit can be manufactured from multiple layers of a clear insulating material, such as polyimide, with horizontal metalization layers between them and vertical metal traces through them. Semiconductor devices, such as thin-film solar cells, can be directly deposited on this substrate to form a flexible electronic module. Additionally, discrete components can be bonded and electrically connected to the circuit. In a typical configuration, a flexible power module could be made with thin-film solar cells deposited on one side and power converters bonded to the other side. The flexible printed circuit board is well suited for forming electronic systems about a curved surface, such as a power sphere for a nanosatellite.

K. Siri, "Maximum Power Tracking Solar Power System," U.S. Patent No. 6,281,485, Aug. 2001.

This maximum-power tracking system enables a power source, such as a solar array, to deliver maximum peak power. The system uses a set-point signal, modulated by a dither signal, to control increasing, decreasing, and steady states of the solar-array voltage. This setup achieves stabilized regular power tracking during periods of low demand and maximum power tracking during periods of high demand. The system can be applied to a constant power load or a highly pulsating load by using two bus stabilizers coupled across the power-input and power-output ports. At a frequency above the central frequency of the bus stabilizers, the system provides proper damping to ensure stability in both input and output voltages without unexpected oscillation. Multiple converters and maximum-power tracking units can be connected in parallel using shared bus control for fault-tolerant equalized power conversion.

C. Sve, P. R. Valenzuela, T. S. Wall, R. W. Francis, R. B. Pan, S. J. VanWormer, "Compartmental Fast Thermal Cycler," U.S. Patent No. 6,271,024, Aug. 2001.

This instrument provides fast thermal-cycle testing of solar cells and similar components. The apparatus has a temperature chamber divided into two compartments. The upper is warmed by heating lamps, and the lower is cooled by liquid nitrogen. Both use pressurized nitrogen gas for thermal conduction and regulation. The test device is mounted to a panel, which is raised and lowered along a vertical track joining the two compartments. The entire chamber is insulated, and the two compartments are thermally isolated from one another, except for the opening through which the test device travels. As a result, neither compartment expends any time recovering to its original operating temperature during use. Computer control enables in-situ electrical testing, failsafe heating, precision temperature control, operator notification, and thermal-gradient control.

Publications

(August 2001–December 2002)

R. N. Abernathy, B. L. Lundblad, and M. P. Keough, "Summary of the Model Validation Program for Rocket Launch Clouds, 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3728.

W. Ailor, "Space Traffic Control—A View of the Future," IAF, 52nd International Astronautical Congress (Toulouse, France, Oct.1–5, 2001), IAF Paper 01-U501.

S. T. Amimoto, D. C. Johannsen, and M. A. Kwok, "Recent Results From the Alpha Laser Performance Test Program," 32nd AIAA Plasmadynamics and Lasers Conference (Anaheim, CA, June 11–14, 2001), AIAA Paper 2001–2867.

E. J. Beiting, "Design and Performance of a Facility to Measure Electromagnetic Emissions from Electric Satellite Thrusters, 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3344.

R. Bitten, N. Lao, and J. Muhle, "Joint Government/Industry Space Programs—Lessons Learned and Recommendations," AIAA Space 2001 Conference and Exposition (Albuquerque, NM, Aug. 28–30, 2001), AIAA Paper 2001–4630.

J. B. Blake et al., "The Global Efficiency of Relativistic Electron Production in the Earth's Magnetosphere," Journal of Geophysical Research, Vol. 106, No. A9, pp. 19,169–19,178 (Sept. 2001).

J. B. Blake, R. S. Selesnick, et al., "Proton Spectra Detected by the Proton Switches on the CRRES Satellite," Journal of Spacecraft and Rockets, Vol. 38, No. 4, pp. 584–589 (Aug. 2001).

J. B. Blake, R. S. Selesnick, et al., "Studies of Relativistic Electron Injection Events in 1997 and 1998," Journal of Geophysical Research, Vol. 106, No. A9, pp. 19,157–19,168 (Sept. 2001).

J. C. Camparo, "Stellar Scintillation and the Atmosphere's Vertical Turbulence Profile," Journal of the Optical Society of America A, Vol. 18, No. 3, pp. 631–637 (Mar. 2001).

W. S. Campbell, M. E. Sorge, A. B. Jenkin, et al., "Orbital Debris Hazard Assessment Methodologies for Satellite Constellations," Journal of Spacecraft and Rockets, Vol. 38, No. 1, pp. 120–125 (Feb. 2001).

D. W. Chen and K. M. Masters, "Continuous-Wave 4.3-mm Intracavity Difference Frequency Generation in an Optical Parametric Oscillator," Optics Letters, Vol. 26, No. 1, pp. 25–27 (Jan. 2001).

J. B. Clark, "Equivalence of Fractional Facto-rial Designs," Statistica Sinica, Vol. 11, No. 2, pp. 537–547 (Apr. 2001).

J. H. Clemmons, "Acceleration Signatures in the Dayside Boundary Layer and the Cusp," Physics Chemical Earth C, Vol. 26, No.1–3, pp. 195–200 (2001).

J. H. Clemmons, "Inhomogeneous Transverse Electric Fields and Wave Generation in the Auroral Region: A Statistical Study," Journal of Geophysical Research, Vol. 106, No. A6, pp. 10,803–10,816 (June 2001).

J. H. Clemmons and R. Pfaff, "The Collision Meter: An Experimental Technique to Measure Charged-Neutral Interactions and Gas Composition in the Upper Atmosphere," Physics and Chemistry of the Earth, Part C, Vol. 26, No. 4, pp. 247–252 (2001).

K. Coste, "Qualification of the Arc 5-lbf Bipropellant Thruster for Deep Pressure Blow-down Operation," 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3988.

M. W. Crofton, "Grid Erosion Analysis of the T5 Ion Thruster," 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3781.

M. W. Crofton and I. D. Boyd, "Plume Measurement and Modeling Results for a Hollow Cathode Micro-Thruster," 37th AIAA/ ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3795.

M. W. Crofton, T. A. Moore, and I. D. Boyd, "Near-Field Measurement and Modeling Results for Flight-Type Arcjet: Hydrogen Atom," Journal of Spacecraft and Rockets, Vol. 38, No. 3, pp. 417–425 (May–June 2001).

K. D. Diamant, J. J. Brandenburg, and R. B. Cohen, "Performance Measurements of a Water Fed Microwave Electrothermal Thruster," 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3900.

S. V. Didziulis and P. P. Frantz, "The Coordination Chemistry of Transition Metal Carbide Surfaces: Detailed Spectroscopic and Theoretical Investigations of CO Adsorption on TiC And VC (100) Surfaces," Journal of Physical Chemistry B, Vol. 105, No. 22, pp. 5196–5209 (2001).

L. Drake and P. Portanova, "Evolved Expendable Launch Vehicle System—the Next Step in Affordable Space Transportation," IAF, 52nd International Astronautical Congress (Toulouse, France, Oct.1–5, 2001), IAF Paper 01-V104.

W. A. Engblom, "A Front-Capture Scheme for the Simulation of Homogeneous and Particle-Laden Gravity Currents," International Journal of Numerical Methods in Fluids, Vol. 35, No. 8, pp. 961–982 (Apr. 2001).

J. F. Fennell, "Dawn-Dusk Asymmetry in Particles of Solar Wind Origin within the Magnetosphere," Annales de Geophysique, Vol. 19, pp. 1–9 (2001).

J. F. Fennell et al., "MeV Magnetosheath Ions Energized at the Bow Shock," Journal of Geophysical Research, Vol. 106, No. A9, pp. 19,101–19,115 (Sept. 2001).

H. F. Fliegel, L. F. Warner, et al., "Photometry of Global Positioning System Block II and IIA Satellites on Orbit," Journal of Spacecraft and Rockets, Vol. 38, No. 4, pp. 609–616 (Aug. 2001).

P. P. Frantz and S. V. Didziulis, "Chemical Modification of the Interfacial Frictional Properties of Vanadium Carbide Through Ethanol Adsorption Surface," Science, Vol. 481, pp. 185–197 (2001).

S. Goldstein, J. A. Lopez, et al., "Testing and Analysis of Detonation Transfer Across a Gap Within a Confined Volume," 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3221.

D. F. Hall et al., "Midcourse Space Experiment (MSX) Satellite Measurements of Contaminant Films Using QCMs—5 Years in Space," 35th AIAA Thermophysics Conference (Anaheim, CA, June 11–14, 2001), AIAA Paper 2001–2956.

M. P. Hickey, G. Schubert, and R. L. Walterscheid, "Acoustic Wave Heating of the Thermosphere," Journal of Geophysical Research, Vol. 106, No. A10, pp. 21,543–21,548 (Oct. 2001).

J. A. Kechichian, "Computational Aspects of Transfer Trajectories to Halo Orbits," Journal of Guidance, Control, and Dynamics, Vol. 24, No. 4, pp. 796–804 (Aug. 2001).

K. K. Khurana, "Energetic Ion Dynamics in Jupiter's Plasma Sheet," Journal of Geophysical Research, Vol. 106, No. A9, pp. 18,895–18,905 (Sept. 2001).

E. E. King, R. C. Lacoe, and J. Wang-Ratkovic, "Influence of the Lightly Doped Drain Resistance on the Worst-Case Hot-Carrier Stress Condition for NMOS Devices," Microelectronics Reliability, Vol. 41, No. 5, pp. 649–660 (May 2001).

H. C. Koons, "Statistical Analysis of Extreme Values in Space Science," Journal of Geophysical Research, Vol. 106, No. A6, pp. 10,915–10,921 (June 2001).

M. A. Kwok, "A Model Predictor for Chemical Laser Combustors," 32nd AIAA Plasmadynamics and Lasers Conference (Anaheim, CA, June 11–14, 2001), AIAA Paper 2001–2868.

C. A. Landauer and K. L. Bellman, "New Architectures for Constructed Complex Systems," Applied Mathematics and Computation, Vol. 120, No. 1–3, pp. 149–163 (May 10, 2001).

C. A. Landauer and K. L. Bellman, "Virtual Worlds as Meeting Places for Formal Systems," Applied Mathematics and Computation, Vol. 120, No. 1–3, pp. 165–173 (May 10, 2001).

K. R. Lorentzen, M. D. Looper, and J. B. Blake, "Relativistic Electron Microbursts During the GEM Storms," Geophysical Research Letters, Vol. 28, No. 13, pp. 2573–2576 (July 2001).

M. W. Maier, "Software Architecture: Introducing IEEE Standard 1471," Computer, Vol. 34, No. 4, pp. 107–109 (Apr. 2001).

J. W. Murdock and R. P. Welle, "Downstream Gas Effect on Nozzle Flow-Separation Location," Journal of Propulsion and Power, Vol. 17, No. 4, pp. 936–938 (Aug. 2001).

D. L. Oltrogge and R. G. Gist, "Experiences with Situational Awareness for Communications Satellite Operations," 19th AIAA International Communications Satellite Systems Conference (Toulouse, France, Apr. 17–20, 2001), AIAA Paper 2001–0075.

J. P. Penn et al., "SPST Collaborative Prioritization of Advanced RLV Technologies Derived from a Bottom-up Process," 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3983.

E. L. Petersen, "An Improved Turbulent Boundary-Layer Model for Shock Tubes," 31st AIAA Fluid Dynamics Conference and Exhibit (Anaheim, CA, June 11–14, 2001), AIAA Paper 2001–2855.

E. L. Petersen, "Measurements of Reflected-Shock Bifurcation in a High-Pressure Shock Tube," 23rd International Symposium on Shock Waves (Arlington, TX, July 22–27, 2001), Paper No. 2377.

E. L. Petersen, "Nonideal Effects Behind Reflected Shock Waves in a High-Pressure Shock Tube," Shock Waves, Vol. 10, pp. 405–420 (2001).

E. L. Petersen, "On the Accuracy of Heterogeneous Shock-Tube Measurements Involving Aerosols," 2nd Joint Meeting, U.S. Sections, Combustion Institute (Oakland, CA, Mar. 25–28, 2001), Paper No. 23.

J. E. Pollard, "A Hall Effect Thruster Plume Model Including Large-Angle Elastic Scattering," 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3355.

J. E. Pollard, "Plume Mass Spectrometry with a Hydrazine Arcjet Thruster," Journal of Spacecraft and Rockets, Vol. 38, No. 3, pp. 411–416 (May–June 2001).

J. E. Pollard, "Validation of Hall Thruster Plume Sputter Model," 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3986.

J. E. Pollard and K. D. Diamant, "Ion Flux, Energy, and Charge-State Measurement for the BPT-4000 Hall Thruster," 37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3351.

J. L. Roeder, "Dominant Role of the Asymmetric Ring Current in Producing the Stormtime Dst," Journal of Geophysical Research, Vol. 106, No. A6, pp. 10,883– 10,904 (June 1, 2001).

J. L. Roeder, "Ground-Based and Polar Spacecraft Observation of a Giant (Pg) Pulsation and Its Association Source Mechanism," Journal of Geophysical Research, Vol. 106, No. A6, pp. 10,837–10,852 (June 1, 2001).

J. L. Roeder, J. F. Fennell, et al., "Energy Content in the Storm Time Ring Current Turner," Journal of Geophysical Research, Vol. 106, No. A9, pp.19,149–19,156 (Sept. 2001).

M. N. Ross, "Chance Encounter with the Stratospheric Kerosene Rocket Plume from Russia over California," Geophysical Research Letters, Vol. 28, No. 6, pp. 959–962 (Mar. 15, 2001).

R. J. Rudy, S. M. Mazuk, D. K. Lynch, R. C. Puetter, and D. S. P. Dearborn, "The Near-Infrared Spectrum of the Planetary Nebula IC 5117," Astronomical Journal, Vol. 121, No. 1), pp. 362–370 (Jan. 2001).

B. A. Shadwick and W. F. Buell, "Unitary Integration with Operator Splitting for Weakly Dissipative Systems," Journal of Physics A: Mathematical and General, Vol. 34, No. 22, pp. 4771–4781 (June 2001).

K. Siri and K. A. Conner, "Fault-Tolerant Scaleable Solar Power Bus Architectures with Maximum Power Tracking," 16th Annual IEEE Applied Power Electronics Conference (Anaheim, CA, Mar. 3–8, 2001), Vol. 2, pp. 1009–1014.

C. Truong, K. Siri, E. J. Simburger, R. C. Lacoe, J. Ross, S. Brown, and A. Prater, "Radiation Test on a Small DC-DC Converter," Government Microcircuit Applications Conference (San Antonio, TX, Mar. 3–8, 2001), pp. 262–265.

G. C. Valley, "Modeling Transient Gain Dynamics in a Cladding-Pumped Yb-Doped Fiber Amplifier Pulsed at Low Repetition Rates," Technical Digest for the Conference on Lasers and Electro-Optics (CLEO), (Baltimore, MD, May 6–11, 2001), pp. 300–301.

M. W. Vanik, "Monitoring Structural Health Using a Probabilistic Measure," Computer-Aided Civil and Infrastructure Engineering, Vol. 16, No. 1, pp. 1–11 (Jan. 2001).

R. L. Walterscheid and M. P. Hickey, "Secular Variation of OI 5577A Airglow in the Mesopause Region Induced by Transient Gravity Wave Packets," Geophysical Research Letters, Vol. 28, No. 4, pp. 701–704 (Feb. 15, 2001).

R. L. Walterscheid and G. G. Sivjee, "Zonally Symmetric Oscillations Observed in the Airglow from South Pole Station," Journal of Geophysical Research, Vol. 106, No. A3, pp. 3645–3654 (Mar. 1, 2001).

J. C. T. Wang, "Modem SRM Ignition Transient Modeling. V-Prospective Developments in CFD Simulation," 37th AIAA/ ASME/SAE/ASEE Joint Propulsion Conference and Exhibit (Salt Lake City, UT, July 8–11, 2001), AIAA Paper 2001–3447.

J. D. White, M. L. La Grassa, M. S. Marlow, and S. Herrin, "Evaluation of Flight Performance of Low Heritage Spacecraft Hardware on STP Vehicles," AIAA Space 2001 Conference and Exposition (Albuquerque, NM, Aug. 28–30, 2001), AIAA Paper 2001–4706.

A. M. Young and S. S. Osofsky, "Active Feedback Circuit for Minimization of Voltage Transients During Pulsed Measurements of Semiconductor Devices," IEEE Transactions on Instrumentation and Measurement, Vol. 50, No.1, pp. 72–76 (Feb. 2001).

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