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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

The CARD Study - What is its impact

Civil aviation research and development policy review covering aircraft noise, congestion, ATC, runway capacity and airport development problems

Syvertson, C. A.↗
NASA NTRS1973

Tracking and Data Relay Satellite System user impact and network compatibility study

The report contains data on antenna configurations for the low data rate users of the Tracking and Data Relay Satellite System (TDRSS). It treats the coverage and mutual visibility considerations between the user satellites and the relay satellites and relates these considerations to requirements of antenna beamwidth and fractional user orbital coverage. A final section includes user/TDRS telecommunication link budgets and forward and return link data rate tradeoffs.

Source record↗
NASA NTRS1979

A study of the potential impacts of space utilization

Because the demand for comprehensive impact analysis of space technologies will increase with the use of space shuttles, the academic social sciences/humanities community was surveyed in order to determine their interests in space utilization, to develop a list of current and planned courses, and to generate a preliminary matrix of relevant social sciences. The academic scope/focus of a proposed social science space-related journal was identified including the disciplines which should be represented in the editorial board/reviewer system. The time and funding necessary to develop a self-sustaining journal were assessed. Cost income, general organizational structure, marking/distribution and funding sources were analyzed. Recommendations based on the survey are included.

Cheston, T. S.↗
NASA NTRS1984

Spacecraft system study: A study to define the impact of laser communication systems on their host spacecraft

The mutual influence of a laser communication system and its host spacecraft and the degree to which the mutual influence limited acquisition, tracking and pointing processes were investigated. A laser klink between a low earth orbiting (LEO) satellite and a geosynchronous earth orbiting (GEO) satellite was used as a baseline. The laser link between satellites was a generic channel transferring 500 Mbps data from the LEO to GEO using the GaAlAs laser as the laser light source. Major aspects of pointing and tracking with a satelliteborne optical system were evaluated including: (1) orbital aspects such as spacecraft relative motions, point ahead, and Sun snd Moon optical noise; (2) burst errors introduced by the electronic and optical noise levels; (3) servo system design and configurations, and the noise sources such as, sensor noise, base motion disturbances, gimbal friction torque noise; (4) an evaluation of the tracking and beacon link and the type of sensors used; (5) the function of the acquisition procedure and an evaluation of the sensors employed; and (6) an estimate of the size, weight and power needed for the satellite system.

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NASA NTRS1985

Space station crew safety alternatives study. Volume 3: Safety impact of human factors

The first 15 years of accumulated space station concepts for Initial Operational Capability (IOC) during the early 1990's was considered. Twenty-five threats to the space station are identified and selected threats addressed as impacting safety criteria, escape and rescue, and human factors safety concerns. Of the 25 threats identified, eight are discussed including strategy options for threat control: fire, biological or toxic contamination, injury/illness, explosion, loss of pressurization, radiation, meteoroid penetration and debris. Of particular interest here is volume three (of five volumes) pertaining to the safety impact of human factors.

Rockoff, L. A.↗
NASA NTRS1988

The origin of the moon: Further studies of the giant impact

A number of technical improvements in the calculations which simulate the most violent event that has occurred to the earth during its history: its collision with the next largest body which was present in its region of accumulation in the early solar system, are discussed. This body was a planet in its own right, an object a little more massive than the planet Mars. The collision created a disk of molten and gaseous debris in orbit around the protoearth, and it is believed that the dissipation of this disk resulted in the formation of the moon. Also discussed is the serendipitous discovery that has emerged from the simulations: the role played by a huge, hot, rotating bar of rock and iron, which is formed immediately after the collision, in transferring angular momentum to much of the rock that is put into orbit, and in robbing the iron of angular momentum so that it falls promptly into the protoearth.

Benz, W.↗
NASA NTRS1990

The impact of IUE on studies of the nova outburst: 1986 to 1990

Developments in understanding the nova outbursts that have occurred since the IUE (International Ultraviolet Explorer) meetings in 1986 and 1988 are outlined. Those developments that have occurred as a direct result of studies with the IUE satellite are emphasized. These involve the four outbursts that occurred in the large Magellanic cloud, the numerous recurrent novae outbursts, and a number of archival studies. As a direct result of IUE studies done since 1986, it is shown that fast novae become super Eddington at maximum, that many novae decline at the same rate, and that neon novae may be more numerous than previously thought. In addition, it is shown that there are differences in the ourburst characteristics between recurrent novae with giant secondaries and those with compact secondaries.

Starrfield, Sumner G.↗
NASA NTRS1995

Theoretical study of hole initiated impact ionization in bulk silicon and GaAs using a wave-vector-dependent numerical transition rate formulation within an ensemble Monte Carlo calculation

In this paper, calculations of the hole initiated interband impact ionization rate in bulk silicon and GaAs are presented based on an ensemble Monte Carlo simulation with the inclusion of a wave-vector-dependent numerical transition rate formulation. The ionization transition rate is determined for each of the three valence bands, heavy, light, and split-off, using Fermi's golden rule with a two-body, screened Coulomb interaction. The dielectric function used within the calculation is assumed to be wave-vector-dependent. Calculations of the field-dependent impact ionization rate as well as the quantum yield are presented. It is found from both the quantum yield results and examination of the hole distribution function that the effective threshold energy for hole initiated impact ionization is relatively soft, similar to that predicted for the corresponding electron initiated ionization events occur more frequently than either heavy or split-offf initiated ionization events in bulk silicon over the applied electric field strengths examined here, 250-500 kV/cm. Conversely,in GaAs, the vast majority of hole initated ionization events originate from holes within the split-off band.

Oguzman, Ismail H.↗