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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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At least 991 records · Page 55

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NASA NTRS1978

Solar power satellites: The Engineering Challenges

Certain elements of solar power satellite design and system engineering studies are reviewed analyzing solar power satellites as a potential baseload electric power source. The complete system concept concept includes not only the satellites and their ground stations, but also the space transportation for delivery of the satellites, piece by piece, into space, and the factories for their construction in space. Issues related to carrying the solar power satellite concept from the present design study phase through implementation of actual hardware are considered. The first issue category is environmental aspects of the SPS systems. The second category of issues is the technology risks associated with achieving the necessary component and subsystem performances. The third category includes the engineering issues associated with carrying out such a large scale project. The fourth issue category is financial: the funding required to bring such a project into being and the costs of the satellites and resulting cost of the power produced as compared to potential alternative energy sources.

Woodcock, G. R.↗

NASA NTRS1978

Effect of temperature on composite sandwich structures subjected to low velocity projectile impact

An experimental investigation was conducted to study the effect of low velocity projectile impact on graphite/epoxy and Kevlar 49- graphite/epoxy sandwich structural components. Testing was performed at moderately low- and high-temperatures to assess the strength degradation of composites as compared to room temperature values. Low energy projectile impact is considered to simulate the damage caused by runway debris such as small rocks, dropping of hand tools during servicing, etc., on secondary aircraft structures fabricated out of composites. The preload and impact energy necessary to cause catastrophic failure were determined. The residual strength of impact-damaged specimens was also measured.

Sharma, A. V.↗

NASA NTRS1979

NASA/FAA general aviation crash dynamics program - A status report

The objective of the Langley Research Center general aviation crash dynamics program is to develop technology for improved crash safety and occupant survivability in general aviation aircraft. The program involves three basic areas of research: controlled full-scale crash testing, nonlinear structural analyses to predict large deflection elasto-plastic response, and load attenuating concepts for use in improved seat and subfloor structure. Both analytical and experimental methods are used to develop expertise in these areas. Analyses include simplified procedures for estimating energy dissipating capabilities and complex computerized procedures for predicting airframe response. These analyses are being developed to provide designers with methods for predicting accelerations, loads, and displacements of collapsing structure. Tests on typical full-scale aircraft and on full- and sub-scale structural components are being performed to verify the analyses and to demonstrate load attenuating concepts.

Thomson, R. G.↗

NASA NTRS1980

Evaluation of solar thermal power plants using economic and performance simulations

An energy cost analysis is presented for central receiver power plants with thermal storage and point focusing power plants with electrical storage. The present approach is based on optimizing the size of the plant to give the minimum energy cost (in mills/kWe hr) of an annual plant energy production. The optimization is done by considering the trade-off between the collector field size and the storage capacity for a given engine size. The energy cost is determined by the plant cost and performance. The performance is estimated by simulating the behavior of the plant under typical weather conditions. Plant capital and operational costs are estimated based on the size and performance of different components. This methodology is translated into computer programs for automatic and consistent evaluation.

El-Gabawali, N.↗

NASA NTRS1981

Description of 0.186-scale model of high-speed duct of national transonic facility

The National Transonic Facility (NTF) is a pressurized cryogenic wind tunnel with a 2.5 m square test section. A 0.186-scale model of the NTF was used to simulate the aerodynamic performance of the components of the high-speed duct of the NTF. These components consist of a wide-angle diffuser, settling chamber, contraction section, test section, model support section, and high-speed diffuser. The geometry of the model tunnel, referred to as the diffuser flow apparatus is described, and some of its operating characteristics are presented.

Gentry, C. L., Jr.↗

NASA NTRS1981

Drift and dispersion studies of ocean-dumped waste using Landsat imagery and current drogues

The drift and dispersion of industrial acid wastes dumped 64 km off the Delaware coast were investigated using 16 Landsat images. Waste plume drift velocities and spread rates were obtained, and principal component analysis was performed to discriminate the acid waste from other pollutants. Waste plumes averaged drifting rates from 0.59 km/hr to 3.39 km/hr into the southwest quadrant, and remained above the thermocline, which formed at depths ranging from 13 m to 24 m. Rapid waste movement toward shore occurred primarily during storms, although plumes were rapidly dispersed and diluted at spread rates in excess of 4 cm/sec. Landsat data analysis also indicates plume width increase of about 1.5 cm/sec during calm sea conditions, which is also in agreement with Falk's (1974) estimates of plume dilution.

Klemas, V.↗

NASA NTRS1982

Commercial jet transport crashworthiness

The results of a study to identify areas of research and approaches that may result in improved occupant survivability and crashworthiness of transport aircraft are given. The study defines areas of structural crashworthiness for transport aircraft which might form the basis for a research program. A 10-year research and development program to improve the structural impact resistance of general aviation and commercial jet transport aircraft is planned. As part of this program parallel studies were conducted to review the accident experience of commercial transport aircraft, assess the accident performance of structural components and the status of impact resistance technology, and recommend areas of research and development for that 10-year plan. The results of that study are also given.

Widmayer, E.↗

NASA NTRS1983

A 20-GHz IMPATT transmitter, summary

A three stage IMPATT diode amplifier capable of a 16 W CW output and a 2 dB bandwidth of 117 MHz was developed. On the component side, high performance circulators with a 0.2 dB insertion loss and bandwidth of 5 GHz were fabricated. State of the art GaAs IMPATT diodes incorporating diamond heat sink and double Read doping profile were also developed. The diodes are capable of a 2.5 W CW output. A few diodes achieved power outputs as high as 3 W. On the circuit side, high gain (up to 12 dB per stage) single diode, multituned circuits capable of 2 GHz and 930 MHx bandwidth were developed as the first and second stages, respectively, of the amplifier. A 12 diode waveguide cavity combiner was developed as the output stage. The output stage utilized commercially available single drift GaAs IMPATT diodes.

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NASA NTRS1984

Progress toward the development of an aircraft icing analysis capability

An overview of the NASA efforts to develop an aircraft icing analysis capability is presented. Discussions are included of the overall and long term objectives of the program as well as current capabilities and limitations of the various computer codes being developed. Descriptions are given of codes being developed to analyze two and three dimensional trajectories of water droplets, airfoil ice accretion, aerodynamic performance degradation of components and complete aircraft configurations, electrothermal deicer, and fluid freezing point depressant deicer. The need for bench mark and verification data to support the code development is also discussed.

Shaw, R. J.↗

NASA NTRS1984

The 20 and 30 GHz MMIC technology for future space communication antenna system

The development of fully monolithic gallium arsenide receive and transmit modules is described. These modules are slated for phased array antenna applications in future 30/20 gigahertz communications satellite systems. Performance goals and various approaches to achieve them are discussed. The latest design and performance results of components, submodules and modules are presented.

Anzic, G.↗

NASA NTRS1981

Industry review: Locomotive dynamic characterization test-analysis

Data are given relative to tests performed on locomotive components. Dynamic characteristics related to safety are described. Suspension systems, shock absorbers, data processing, bearings, and damping are discussed.

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NASA NTRS1985

Advances in sputtered and ion plated solid film lubrication

The glow discharge or ion assisted vacuum deposition techniques, primarily sputtering and ion plating, have rapidly emerged and offer great potential to deposit solid lubricants. The increased energizing of these deposition processes lead to improved adherence and coherence, favorable morphological growth, higher density, and reduced residual stresses in the film. These techniques are of invaluable importance where high precision machines tribo-components require very thin, uniform lubricating films (0.2 m), which do not interface with component tolerances. The performance of sputtered MoS2 films and ion plated Au and Pb films are described in terms of film thickness, coefficient of friction, and wear lives.

Spalvins, T.↗

NASA NTRS1984

Investigation of test methods, material properties, and processes for solar cell encapsulants

Photovoltaic (PV) modules consist of a string of electrically interconnected silicon solar cells capable of producing practical quantities of electrical power when exposed to sunlight. To insure high reliability and long term performance, the functional components of the solar cell module must be adequately protected from the environment by some encapsulation technique. The encapsulation system must provide mechanical support for the cells and corrosion protection for the electrical components. The goal of the program is to identify and develop encapsulation systems consistent with the PV module operating requirements of 30 year life and a target cost of $0.70 per peak watt ($70 per square meter) (1980 dollars). Assuming a module efficiency of ten percent, which is equivalent to a power output of 100 watts per square meter in midday sunlight, the capital cost of the modules may be calculated to be $70.00 per square meter. Out of this cost goal, only 20 percent is available for encapsulation due to the high cost of the cells, interconnects, and other related components. The encapsulation cost allocation may then be stated as $14.00 per square meter, included all coatings, pottant and mechanical supports for the cells.

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NASA NTRS1984

Progress toward the development of an aircraft icing analysis capability

Shaw, R. J.↗

NASA NTRS1984

Uprated orbital maneuvering engine

The baseline orbital maneuvering system (OMS) of the Space Shuttle has the potential for significant performance uprating, leading to increased Shuttle payload capability. The baseline OMS, its requirements, and its operational characteristics are described. Potential uprating approaches are discussed and the logic for selection of a higher performance engine is presented. It is shown that a higher performance engine essentially means an engine operating at higher pressures and that a pump-fed engine is necessary for the higher pressure operation. A description of the uprated OMS engine, including requirements, baseline engine characteristics, and significant engine issues, is presented. Discussion of the program underway at the NASA Lyndon B. Johnson Space Center to attain additional insight into these issues, through the performance of a component demonstration program, includes the technical objectives, approach, and program schedule. The plans for further development are presented, culminating in the plans for integration with the Orbiter and the Shuttle system.

Hooper, J. C.↗

NASA NTRS1986

NASA's Aircraft Icing Analysis Program

An overview of the NASA ongoing efforts to develop an aircraft icing analysis capability is presented. Discussions are included of the overall and long term objectives of the program as well as current capabilities and limitations of the various computer codes being developed. Descriptions are given of codes being developed to analyze two and three dimensional trajectories of water droplets, airfoil ice accretion, aerodynamic performance degradation of components and complete aircraft configurations, electrothermal deicer, fluid freezing point depressant antideicer and electro-impulse deicer. The need for bench mark and verification data to support the code development is also discussed, and selected results of experimental programs are presented.

Shaw, R. J.↗

NASA NTRS1986

NASA's aircraft icing analysis program

An overview of the NASA ongoing efforts to develop an aircraft icing analysis capability is presented. Discussions are included of the overall and long term objectives of the program as well as current capabilities and limitations of the various computer codes being developed. Descriptions are given of codes being developed to analyze two- and three-dimensional trajectories of water droplets, airfoil ice accretion, aerodynamic performance degradation of components and complete aircraft configurations, electrothermal deicer, fluid freezing point depressant antideicer and electro-impulse deicer. The need for bench mark and verification data to support the code development is also discussed, and selected results of experimental programs are presented.

Shaw, R. J.↗

NASA NTRS1986

Progress in coherent laser radar

Considerable progress with coherent laser radar has been made over the last few years, most notably perhaps in the available range of high performance devices and components and the confidence with which systems may now be taken into the field for prolonged periods of operation. Some of this increasing maturity was evident at the 3rd Topical Meeting on Coherent Laser Radar: Technology and Applications. Topics included in discussions were: mesoscale wind fields, nocturnal valley drainage and clear air down bursts; airborne Doppler lidar studies and comparison of ground and airborne wind measurement; wind measurement over the sea for comparison with satellite borne microwave sensors; transport of wake vortices at airfield; coherent DIAL methods; a newly assembled Nd-YAG coherent lidar system; backscatter profiles in the atmosphere and wavelength dependence over the 9 to 11 micrometer region; beam propagation; rock and soil classification with an airborne 4-laser system; technology of a global wind profiling system; target calibration; ranging and imaging with coherent pulsed and CW system; signal fluctuations and speckle. Some of these activities are briefly reviewed.

Vaughan, J. M.↗