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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 1,099 records · Page 61
All sourcesNASA NTRSDOE OSTI
NASA NTRS1963

METEORITIC TIME-OF-FALL PATTERNS

Decade, yearly and monthly distributions of meteorite time-of-fall patterns are examined, noting departures from randomness

METEORITE↗
NASA NTRS1963

THE ATMOSPHERE OF MARS

Martian atmosphere examined through its redness, its albedo and its surface markings, noting also the composition of its two layers of particulate matter

ATMOSPHERIC COMPOSITION↗
NASA NTRS1960

The Lunar Environment

The NASA lunar exploration program has focused the attention of many scientific and technical groups on such questions as the relative value of lunar experiments, the advantages of manned versus unmanned exploration, and the proper time sequence for the steps to be taken in the exploration program. It is interesting to note that all the approaches to the problem require a definition of the lunar environment at an early stage in the program. The choice of scientific experiments and the design of the required instrumentation is based on our present knowledge of the Moon and on educated guesses as to what data may be obtained. The technical developments required to make possible both a lunar landing and continued operation of scientific equipment on the lunar surface also demand a definition of the lunar environment as a design condition.

Buwalda, Phyllis↗
NASA NTRS1960

Some Characteristics of the Signal Received from 1958 Delta 2

The study of the rapid fluctuation in the received signal strength from artificial earth satellites has led to a better understanding of the irregularities in electron density which exist in the ionosphere. In particular, the dimensions and locations of these inhomogeneities have been investigated. This note may serve as additional confirmation of some of the work mentioned above and, in addition, will report several new features of the received satellite radio signals.

De Mendonca, F.↗
NASA NTRS1956

An Engineering Approach to the Variable Fluid Property Problem in Free Convection

An analysis is made for the variable fluid property problem for laminar free convection on an isothermal vertical flat plate. For a number of specific cases, solutions of the boundary layer equations appropriate to the variable property situation were carried out for gases and liquid mercury. Utilizing these findings, a simple and accurate shorthand procedure is presented for calculating free convection heat transfer under variable property conditions. This calculation method is well established in the heat transfer field. It involves the use of results which have been derived for constant property fluids, and of a set of rules (called reference temperatures) for extending these constant property results to variable property situations. For gases, the constant property heat transfer results are generalized to the variable property situation by replacing beta (expansion coefficient) by one over T sub infinity and evaluating the other properties at T sub r equals T sub w minus zero point thirty-eight (T sub w minus T sub infinity). For liquid mercury, the generalization may be accomplished by evaluating all the properties (including beta) at this same T sub r. It is worthwhile noting that for these fluids, the film temperature (with beta equals one over T sub infinity for gases) appears to serve as an adequate reference temperature for most applications. Results are also presented for boundary layer thickness and velocity parameters.

Gregg, J. L.↗
NASA NTRS1963

Simulation of atmospheric drag

To accurately simulate the trajectory of an artificial satellite or space probe, the deceleration from atmospheric drag must be considered. In addition to the Earth, there is evidence that Mars, Venus and Jupiter have sufficiently dense atmospheres to affect the motion of a space vehicle. This paper discusses some problems involved in simulating planetary atmospheres themselves, and the results of making certain simplifying assumptions. The object of this report is to come up with a recommendation for a method of simulating atmospheric drag representing a complexity commensurate with the state of the art. It should be noted that the mission of ·the vehicle has to be considered. There are three missions in which atmospheric drag could play an important part. The first mission is a low eccentricity orbit about the Earth or another planet. The second mission is a planetary re-entry and .the third is a flyby orbit of the space vehicle. The three cases will be referred to as the "orbiting'", "reentry" and "fly -by" cases.

COMPUTER SIMULATION↗
NASA NTRS1964

Comments on exhaust flow field and surface impingement

In recent months there has been interest in the problem of the impingement of a jet exhaust on simulated lunar surfaces. The problem has been described both experimentally and theoretically. In the June issue of the AIAA Journal there appeared two Technical Notes that seemed to complicate unnecessarily the analysis of the free-jet expansion and the surface pressure distribution. The purpose of the present comment is to recall briefly the simple results of the theory and to make a more complete comparison with the experiniental data of Ref. 1

LUNAR SURFACE↗
NASA NTRS1963

Radiation studies on gaas and si devices.

Effects of nuclear radiation on gallium arsenide and silicon solar cells, noting performance difference in terms of initial lifetime and photo- absorption process

GALLIUM ARSENIDE↗
NASA NTRS1964

Fuel cells - 1963.

Recent progress in fuel cell research, noting particularly the hardware stage

FUEL CELL↗
NASA NTRS1964

Food in flight.

Food for astronauts during space flights, noting problems and peculiar aspects of eating and drinking in space environment

MANNED SPACE FLIGHT↗