Engineering topics

Hickman, D. R.

Publications and source records attributed to Hickman, D. R..

5 records

NASA NTRS1979

User requirements of solar-terrestrial predictions for spacecraft applications

Areas which are influenced by solar-terrestrial coupling effects and which are internal to the Earth's magnetosphere are of interest to mission planners, spacecraft hardware designers, and those engaged in the operation of already orbiting manned or unmanned spacecraft. Accurate models are needed to predict energetic particle flux density, interactions between low energy (10 eV to 100 eV) near-Earth plasma and space systems, and neutral atmospheres. Parameters required for each of these areas are discussed.

Vampola, A. L.↗

NASA NTRS1979

Predictability of upper-atmospheric density and composition

Empirical models of upper-atmospheric density and composition are employed in a number of areas, ranging from basic research in atmospheric and ionospheric physics to practical applications in satellite ephemeris prediction. Such models are based on various kinds of data sets and have varying levels of complexity, strengths, and weaknesses. The characteristics of several of the widely used models are described and studies in which the predictions of these models were compared with observational data are reviewed. The relative advantages and limitations of the models in current use are discussed as well as ways in which the models might be improved.

Straus, J. M.↗

NASA NTRS1973

The open-source neutral-mass spectrometer on Atmosphere Explorer-C, -D, and -E.

The open-source mass spectrometer will be used to obtain the number densities of the neutral atmospheric gases in the mass range 1 to 48 amu at the satellite location. The ion source has been designed to allow gas particles to enter the ionizing region with the minimum practicable number of prior collisions with surfaces. This design minimizes the loss of atomic oxygen and other reactive species due to reactions with the walls of the ion source. The principal features of the open-source spectrometer and the laboratory calibration system are discussed.

Nier, A. O.↗

NASA NTRS1973

Study of neutral composition of lower thermosphere at Fort Churchill.

On Feb. 4 and 6, 1969, and May 11, 1970, Aerobee rockets carrying neutral mass spectrometers were flown at Fort Churchill, Canada during conditions of low geomagnetic activity. As in earlier flights at White Sands, New Mexico, each rocket carried both 'open' and 'closed' ion source instruments. Vertical profiles of N2, O2, O, Ar, and He were measured. Results obtained were essentially the same as those observed at White Sands except that for the winter flights helium appeared to be in diffusive equilibrium.

Nier, A. O.↗

NASA NTRS1972

Measurement of the neutral composition of the lower thermosphere above Fort Churchill by rocket-borne mass spectrometer.

Measurement of the neutral atmospheric composition above Fort Churchill, Canada (59 N, 94 W), by mass spectrometers in two rocket flights at 0835 CST on Feb. 4 and 6, 1969. A quantitative measure for the extent of agreement with static diffusive equilibrium is introduced, and substantial agreement with profiles predicted when static diffusive equilibrium was assumed is found for all constituents including helium. A sensitive search for atomic nitrogen yielded upper limits of a few per cent for one flight and of 0.2% for the other.

Hickman, D. R.↗