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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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The NASA Glenn Research Center and the Cleveland State University have developed a digitally controlled dc-dc converter to research the benefits of flexible, digital control on power electronics and systems. Initial research and testing has shown that conventional dc-dc converters can benefit from improved performance by using digital-signal processors and nonlinear control algorithms.
Electric propulsion systems are quickly emerging as attractive options for primary propulsion in low Earth orbit, in geosynchronous orbit, and on interplanetary spacecraft. The driving force behind the acceptance of these systems is the substantial reduction in the propellant mass that can be realized. Unfortunately, system designers are often forced to utilize components designed for chemical propellants in their electric systems. Although functionally acceptable, these relatively large, heavy components are designed for the higher pressures and mass flow rates required by chemical systems. To fully realize the benefits of electric propulsion, researchers must develop components that are optimized for the low flow rates, critical leakage needs, low pressures, and limited budgets of these emerging systems.
Analytical and experimental studies conducted at the NASA, Langley Research Center (LaRC) for investigating integrated cryogenic propellant tank systems for a reusable launch vehicle (RLV) are described. The cryogenic tanks are investigated as an integrated tank system. An integrated tank system includes the tank wall, cryogenic insulation, thermal protection system (TPS) attachment sub-structure, and TPS. Analysis codes are used to size the thicknesses of cryogenic insulation and TPS insulation for thermal loads, and to predict tank buckling strengths at various ring frame spacings. The unique test facilities developed for the testing of cryogenic tank components are described. Testing at cryogenic and high-temperatures verifies the integrity of materials, design concepts, manufacturing processes, and thermal/structural analyses. Test specimens ranging from the element level to the subcomponent level are subjected to projected vehicle operational mechanical loads and temperatures. The analytical and experimental studies described in this paper provide a portion of the basic information required for the development of light-weight reusable cryogenic propellant tanks.
The operational envelope of gas turbine engines is constrained by the stability limit of the compression system. The dangers of exceeding this limit are severe, with the potential for engine failure and loss of the aircraft. To avoid such failures, compressor designers provide an adequate stability (stall) margin in the compressor design to account for inlet distortions, degradation due to wear, throttle transients, and other factors that reduce compressor stability from the original design intent. In some cases, the required stall margin results in the compressor operating line being below the maximum efficiency potential of the compression system. Current approaches to increasing stability tend to decrease the efficiency of the compressor. The focus of this work is to increase the stall margin of compressors without decreasing their efficiency.
The objective of this proposal was to build and demonstrate a new direct-detection diffraction grating concept and couple it to an array of bolometers. The spectrometer was to be built around a parallel-plate waveguide diffraction grating, WaFIRS: Waveguide Far-InfraRed Spectrometer. The grating is two dimensional in nature, which provides a compact configuration to suit NASA s needs for cryogenic spectrometers for future opportunities, such as infrared/submillimeter spectrometers for a suborbital balloon platform, for SOFIA, for SPICA (a Japanese satellite), and for SAFIR. Our goal was to build a spectrometer (Z-Spec) for 1.0 - 1.5 mm and demonstrate spectral resolution, throughput, and background-limited performance. This grant would partially cover the expenses and we were subsequently awarded a second grant, NAGS-12788, to complete the project. We have one-year received a no-cost extension on NAG.5-12788, to be completed in 3/31/06.
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This paper describes several Jet Propulsion Laboratory research efforts being conducted to support Mars sample return in the coming decade.
The Vision of the MTD perogram is to be the most innovative spacecraft technolgy developers in the world.
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