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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 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

The relative importance of noise level and number of events on human reactions to noise: Community survey findings and study methods

The data from seven surveys of community response to environmental noise are reanalyzed to assess the relative influence of peak noise levels and the numbers of noise events on human response. The surveys do not agree on the value of the tradeoff between the effects of noise level and numbers of events. The value of the tradeoff cannot be confidently specified in any survey because the tradeoff estimate may have a large standard error of estimate and because the tradeoff estimate may be seriously biased by unknown noise measurement errors. Some evidence suggests a decrease in annoyance with very high numbers of noise events but this evidence is not strong enough to lead to the rejection of the conventionally accepted assumption that annoyance is related to a log transformation of the number of noise events.

Fields, J. M.↗
NASA NTRS1980

Civil helicopter wire strike assessment study. Volume 1: Findings and recommendations

Approximately 208 civil helicopter wire strike accidents for a ten year period 1970 to 1979 are analyzed. It is found that 83% of the wire strikes occurred during bright clear weather. Analysis of the accidents is organized under pilot, environment, and machine factors. Methods to reduce the wire strike accident rate are discussed, including detection/warning devices, identification of wire locations prior to flight, wire cutting devices, and implementation of training programs. The benefits to be gained by implementing accident avoidance methods are estimated to be fully justified by reduction in injury and death and reduction of aircraft damage and loss.

Tuomela, C. H.↗
NASA NTRS1979

A reconsideration of nucleation phenomena in light of recent findings concerning the properties of small clusters, and a brief review of some other particle growth processes

The paper examines mechanisms of nucleation and growth by condensation and coagulation in the light of recent research on properties of small clusters. Homogeneous, hetero-molecular, and heterogeneous nucleation is analyzed, and expressions for the rate of formation of a stable condensed phase and evaluation of the free energy of formation of charged droplets are given. Application of high-pressure mass spectrometry which makes possible a direct determination of intensity spectra for cluster distributions, measurement of the thermodynamic properties of individual ion clusters and determination of cluster entropy and bond energy is discussed. Finally, coagulation of the condensed phase is considered, noting that concentration and mean particle size vary during coagulation, but the shape distribution is time independent, leading to the concept of a self-preserving aerosol size distribution.

Castleman, A. W., Jr.↗
NASA NTRS1979

The implications and limitations of the findings of the Viking organic analysis experiment

The gas chromatograph mass spectrometer instrument of the Viking mission has demonstrated the absence of organic compounds in the immediate surface layer of the two landing sites. The demonstration of the successful operation of the instrument (comparison of ground-based test data with those obtained during interplanetary flight and the data from the surface of the planet) and its limitations (e.g., the detection of highly cross-linked polymers or polymeric carbon suboxide) are reviewed. The measurements for bound water are based on indirect data, the detectability of evolved carbon dioxide and ammonia is poor, and oxygen, liberated from the soil samples, can not be detected.

Biemann, K.↗
NASA NTRS1977

Annual Report to the NASA Administrator by the Aerospace Safety Advisory Panel on the Space Shuttle Program. Part 2: Summary of Information Developed in the Panel's Fact-Finding Activities

The panel focused its attention on those areas that are considered most significant for flight success and safety. Elements required for the Approach and Landing Test Program, the Orbital Flight Test Program, and those management systems and their implementation which directly affect safety, reliability, and quality control, were investigated. Ground facilities and the training programs for the ground and flight crews were studied. Of special interest was the orbiter thermal protection subsystems.

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NASA NTRS1976

Annual report to the NASA Administrator by the Aerospace Safety Advisory Panel on the space shuttle program. Part 2: Summary of information developed in the panel's fact-finding activities

Safety management areas of concern include the space shuttle main engine, shuttle avionics, orbiter thermal protection system, the external tank program, and the solid rocket booster program. The ground test program and ground support equipment system were reviewed. Systems integration and technical 'conscience' were of major priorities for the investigating teams.

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NASA NTRS1975

Annual report to the NASA Administrator by the Aerospace Safety Advisory Panel. Part 2: Space shuttle program. Section 2: Summary of information developed in the Panel's fact-finding activities

The management areas and the individual elements of the shuttle system were investigated. The basic management or design approach including the most obvious limits or hazards that are significant to crew safety was reviewed. Shuttle program elements that were studied included the orbiter, the space shuttle main engine, the external tank project, solid rocket boosters, and the launch and landing elements.

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NASA NTRS1980

Ground experiments for finding principles and working out methods for preventing adverse effects of weightlessness on the human organism

A comparative assessment of the effectiveness of different prophylactic procedures to prevent the adverse effects of weightlessness is presented. It is concluded that: physical training is most effective but no single method by itself produces the full effect, and an adjustment of regimes to one another enhances the effect. The approved complex of prophylactic procedures affected basic changes occurring in hypokinesia: deficit of muscular activity, no or reduced BP hydrostatic component, reduced volume of blood circulation, reduced hydration level, and the application of various prophylactic complexes during 49 day antiorthostatic hypodynamia eliminated or reduced the adverse effects of weightlessness in simulation.

Kakurin, L. I.↗
NASA NTRS1980

Seasat: - JASIN workshop report. Volume 1: Findings and conclusions

Data acquired from the Joint Air-Sea Interaction (JASIN) Experiment and Seasat data from overpasses that covered the JASIN area were compared and evaluated. The JASIN data were used as a high quality withheld data set. The Seasat data were prepared for each instrument: the Seasat-A Satellite Scatterometer (SASS), the Scanning Multichannel microwave radiometer (SMMR), and the synthetic aperture radar (SAR). The following results demonstrate the performance of Seasat: it was possible to identify mesoscale systems with the SASS as well as fronts; the SMMR provided accurate water vapor content of the atmosphere; the SAR showed evidence of helical rolls in the marine boundary layer; a SASS anomaly could be traced back to thunderstorm activity.

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NASA NTRS1979

Finding the times that SMMR observed a ship

In order to facilitate the coincidence calculations, the coordinates of the ship and the satellite were transformed to the ECO system in which the equatorial plane is the plane of the satellite's orbit. The transformation matrices for each step are presented. The ship could be observed when it was in a band about the equator in the ECO system. The width of the band was determined by the scan pattern of the instrument.

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NASA NTRS1981

Data acquisition and analysis of range-finding systems for spacing construction

For space missions of future, completely autonomous robotic machines will be required to free astronauts from routine chores of equipment maintenance, servicing of faulty systems, etc. and to extend human capabilities in hazardous environments full of cosmic and other harmful radiations. In places of high radiation and uncontrollable ambient illuminations, T.V. camera based vision systems cannot work effectively. However, a vision system utilizing directly measured range information with a time of flight laser rangefinder, can successfully operate under these environments. Such a system will be independent of proper illumination conditions and the interfering effects of intense radiation of all kinds will be eliminated by the tuned input of the laser instrument. Processing the range data according to certain decision, stochastic estimation and heuristic schemes, the laser based vision system will recognize known objects and thus provide sufficient information to the robot's control system which can develop strategies for various objectives.

Shen, C. N.↗
NASA NTRS1980

Gomez, Terry County, Texas - A new meteorite find

The Gomez meteorite, weighing slightly over 47 kg, was found near the town of Gomez, Terry County, Texas (33 deg 10 min 53 sec N, 102 deg 24 min 5 sec W) prior to 1974. It is a highly weathered, equilibrated L-6 chondrite of composition Fa 26, Fs 23. A large number of chromite grains and possibly partially weathered lawrencite grains were noted.

Sipiera, P. P.↗
NASA NTRS1981

The Correo and Suwanee Spring meteorites - Two new ordinary chondrite finds

Two new ordinary chondrites were found about 40 km west of Albuquerque, New Mexico. Correo is an H4 chondrite with distinct chondrules and major olivine (Fo 81.4), orthopyroxene (En 82.3) and plagioclase (An 12). Suwanee Spring is an L5 chondrite with few distinct chondrules and a highly recrystallized matrix. Major minerals are olivine (Fo 75.4), orthopyroxene (En 77.7) and plagioclase (An 9). The metallic Ni-Fe phases of both meteorites are typical of slowly cooled ordinary chondrites.

Rubin, A. E.↗
NASA NTRS1981

Wedge-and-strip anodes for centroid-finding position-sensitive photon and particle detectors

The paper examines geometries employing position-dependent charge partitioning to obtain a two-dimensional position signal from each detected photon or particle. Requiring three or four anode electrodes and signal paths, images have little distortion and resolution is not limited by thermal noise. An analysis of the geometrical image nonlinearity between event centroid location and the charge partition ratios is presented. In addition, fabrication and testing of two wedge-and-strip anode systems are discussed. Images obtained with EUV radiation and microchannel plates verify the predicted performance, with further resolution improvements achieved by adopting low noise signal circuitry. Also discussed are the designs of practical X-ray, EUV, and charged particle image systems.

Martin, C.↗
NASA NTRS1982

Finding the Focal Axes of Offset Antennas

Focal axis of offset paraboloidal reflector antennas determined by direct measurement instead of trial and error. Two feed horns transmit sum or difference pattern to antenna under test, which reflects energy to far-field detector. When axis of feed horns coincides with focal axis of antenna reflector, far-field detector records minimum in amplitude difference and maximum in absolute-magnitude phase difference between sum and difference signals.

Schmidt, R. F.↗
NASA NTRS1980

SPS structural dynamics and control workshop: Findings and recommendations

The structural dynamics and control of the Solar Power Satellite (SPS), a concept which holds promise for meeting a portion of the energy needs of the United States beyond the year 2000 are examined. The assumptions, methodologies and conclusions of existing SPS studies in the areas of structural dynamics and control (with structural design and materials also being considered) are assessed.

Ried, R. C.↗
NASA NTRS1980

Program Assessment Report Statement of Findings: Satellite Power Systems Concept Development and Evaluation Program

This report states what is known, uncertain, and unknown about the Solar Power Satellite (SPS) concept - collecting solar energy in space and delivering the energy to Earth for the production of baseload electricity. This report discusses the important technical, environmental, and cost goal questions that must be answered prior to making a commitment to the SPS concept. Although significant technological, environmental and economic questions remain to be answered, the preliminary investigations undertaken in the Concept Development and Evaluation Program do provide a basis for a policy decision on further commitment. This report also suggests areas of research and experimentation required to acquire the knowledge by which a series of informed, time-phased decisions may be made concerning the possibility of the SPS concept playing a major role in the United States' energy future.

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