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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Identification of satellites possibly active during the IMS and their orbital configurations

A survey has been made to identify presently operating as well as planned spacecraft which may contribute measurements of the magnetosphere or interplanetary medium during the IMS. The total set consists of 25 scientific earth-orbiting, 9 heliocentric, and 17 communication, navigation or meteorological spacecraft, which carry environmental monitoring experiments. The orbital elements of each are displayed. In addition, techniques for the display of positions in various orbits are presented to illustrate how interesting configurations can be determined during the IMS. The positions of presently orbiting heliocentric spacecraft are shown at various intervals with respect to the nominal interplanetary magnetic field spiral and the earth. Plots of the latest ISEE-A orbit in solar magnetospheric co-ordinates are presented to determine neutral-sheet crossing.

Vette, J. I.↗
NASA NTRS1977

IMS/Satellite Situation Center report. Daily summary for IMS high-altitude satellites, days 182-365 1977

The orbital positions of a number of high-altitude satellites, capable of making magnetospheric measurements in the second half of 1977, are described. The following satellites are considered: Vela 5A, Vela 5B, Vela 6A, Vela 6B, Solrad 11A, Solrad 11B, Hawkeye 1, Prognoz 5, Explorer 47, Explorer 50, and ISEE-A/-B. The orbit elements used for generating the satellite ephemeris are shown. Complete presentations of the positions of these satellites for the second half of 1977 are given, as well as the IMS/SSC special periods. Detailed plots illustrating these periods are provided. Time-ordered tables of magnetopause crossings, bow shock crossings, neutral sheet passes, midlatitude magnetotail passes, high-latitude magnetotail passes, and Hawkeye 1 northern cusp passes are presented. Bar charts covering the second half of 1977 are given which identify thirteen special periods (Nos. 10-22) based upon certain conjunctions of the high-altitude satellites.

Source record↗
NASA NTRS1977

Investigation of environmental change pattern in Japan. Investigation of variations in the prominent oceanic current, Kuroshio

The author has identified the following significant results. It was confirmed that band 4 and 5 had some information as to the sea surface, such as spreading of coastal waters or eddy-like motion of surface water. It was concluded that the front line along the coast from Kumano-nada to Shiono-misaki in the monochromatic prints and in the pseudocolor images was a boundary between coastal waters and offshore water. Most of Ise Bay was covered by polluted water, having salinity values less than 30%, high water color scale of 6 to 8, and transparency less than 5 m.

Maruyasu, T.↗
NASA NTRS1977

Formulation of electrically conductive, thermal-control coatings

Formulation of electrically conductive, thermal-control coatings was undertaken for use on the International Sun Earth Explorer (ISEE) spacecraft. Unsuccessful formulation efforts as well as the successful use of oxide pigments fired at 1175 C are described. Problems attributed to reactivity of specific coating vehicles exposed to high humidity are discussed. Measurement and testing methods, including resulting data are mentioned, but the emphasis, in this report, is placed on coating formulation and application techniques. Methods of varying, as desired, optical properties are also described as well as formulations of white, low-absorptance coatings.

Shai, M. C.↗
NASA NTRS1977

Investigation of conductive thermal control coatings by a contactless method in vacuo

A technique for determining the conductance per unit area of thermal control coatings for electrostatically clean spacecraft is described. In order to simulate orbital conditions more closely, current-density-voltage (j-V) curves are obtained by a contactless method in which the paint on an aluminum substrate is the anode of a vacuum diode configuration with a tungsten filament cathode. Conductances per unit area which satisfy the International Sun Earth Explorer (ISEE) requirement were observed on black paints containing carbon and in white and green paints filled with zinc oxide which were fired in order to induce defect conductivity. Because of surface effects and the nonhomogeneous nature of paints, large discrepancies were found between measurements with the contactless method and measurements employing metallic contacts, particularly at low current densities. Therefore, measurements with metallic contacts are considered to be of questionable value in deciding the suitability of coatings for electrostatic charge control.

Viehmann, W.↗
NASA NTRS1978

Formulation of electrically conductive thermal-control coatings

The development and formulation of electrically conductive thermal control coating was undertaken for use on the International Sun Earth Explorer spacecraft. The primary effort was to develop a coating with a bulk resistivity of less than 100,000 ohm/sqm, an optical absorptance of approximately 0.55, and a normal emittance of 0.90. The required stability in space called for a bulk resistivity of less than 100,000 ohm/sq m, an absorptance of less than 0.67, and a normal emittance of 0.90 after exposure to approximately 4 x 10 to the 16th proton/sq cm of solar-wind particles and 5300 equivalent sun-hours. These exposures represent 2 years of ISEE flight conditions. Both the unsuccessful formulation efforts and the successful use of oxide pigments fired at 1448 K are described. Problems relative to the reactivity of specific coating vehicles exposed to high humidity are discussed.

Shai, M. C.↗
NASA NTRS1978

Ongoing data reduction, theoretical studies

A nonspecific review of theory, correlative date analysis and supporting research and technology is presented. Title pages in some of the following areas are included: (1) magnetosphere boundary observations; (2) venus ionosphere and solar wind interaction; (3) ISEE-C plasma wave investigation, and (4) solar system plasmas.

Scarf, F. L.↗
NASA NTRS1977

Halo orbit station keeping for International Sun-Earth Explorer-C /ISEE-C/

The ISEE-C spacecraft must be kept close to an unstable 'halo' orbit with a series of discrete orbital maneuvers set at intervals at least one month apart. A numerical algorithm has been developed to compute a velocity correction at any point on the trajectory which will minimize the distance between the satellite orbit and the nominal halo path. This algorithm is used to generate a number of station keeping histories with fixed time intervals between maneuvers to ascertain bounds on fuel cost, tightness of fit to nominal path and expected duration between thrust applications. The difference between a third order analytic representation of the halo orbit and a numerically improved nominal path as a reference orbit in the station keeping scheme is investigated as well as the distinction between a tight control and a loose control. A simulation of an operational approach to station keeping is also presented which shows that intermittant propulsive maneuvers can be used to control the spacecraft with very modest fuel expenditure.

Heuberger, H.↗
NASA NTRS1978

Two-scale-factor universality near the critical point of fluids

Thermodynamic data from interferometric density profile studies and light-scattering experiments near the critical isochore of Xe, CO2 and SF6 provide a basis for examining the hypothesized two-scale-factor universality for the correlation function of fluids near the gas-liquid critical point. For the investigation, three-scale-factor universality is assumed, with Ising-like critical exponent values obtained through the renormalization group technique. The two thermodynamic scale factors are found from the density profiles, while the scale factor for the correlation length is obtained from the light-scattering data.

Sengers, J. V.↗
NASA NTRS1978

An experiment to measure interplanetary and solar electrons

The paper describes an ISEE experiment designed to study interplanetary and solar electrons in the energy range between solar wind and galactic cosmic rays. The instrumentation is designed to identify and measure electron fluxes with high energy resolution and high sensitivity from approximately 2 keV to 1 MeV. Angular distributions of these electrons will also be obtained; in addition, energetic ions above 50 keV will be measured. Measurements of particle acceleration in solar flares, solar radio emission, interplanetary particles and shock wave acceleration, and low energy electron propagation are discussed. The instrumentation is described with emphasis on the semiconductor telescopes, the electrostatic analyzer, and the electronics.

Anderson, K. A.↗
NASA NTRS1978

Ion composition experiment

An investigation using a novel ion mass spectrometer for measuring the ionic composition of the solar wind from the ISEE-C spacecraft is described. The resolution and dynamic range of the instrument are sufficient to be able to resolve up to twelve individual ions or groups of ions. This will permit the solution of a number of fundamental problems related to solar abundances and the formation of the solar wind. The spectrometer is composed of a stigmatic Wien filter and hemispherical electrostatic energy analyzer. The use of curved electric field plates in the filter results in a substantial saving of weight with respect to a conventional filter of the same resolution and angular acceptance. The spectrometer is controlled by a microprocessor based on a special purpose computer which has three modes of operations: full and partial survey modes and a search mode. In the search mode, the instrument locks on to the solar wind. This allows four times the time resolution of the full survey mode and yields a full mass spectrum every 12.6 min.

Coplan, M. A.↗
NASA NTRS1978

A cosmic ray isotope spectrometer

The paper describes a new instrument to be flown on ISEE-C which is optimized to measure the isotopic composition of solar and galactic cosmic rays in the 5-250 MeV/nucleon range. A mass resolution of not greater than 0.3 AMU should be achieved for all elements with charge Z not exceeding 30.

Althouse, W. E.↗
NASA NTRS1978

An experiment to study energetic particle fluxes in and beyond the earth's outer magnetosphere

This experiment is designed to take advantage of the ISEE Mother/Daughter dual spacecraft system to study energetic particle phenomena in the earth's outer magnetosphere and beyond. Large geometric factor fixed voltage electrostatic analyzers and passively cooled semiconductor detector telescopes provide high time resolution coverage of the energy range from 1.5 to 300 keV for both ions and electrons. Essentially identical instrumentation is placed on the two spacecraft to separate temporal from spatial effects in the observed particle phenomena.

Anderson, K. A.↗
NASA NTRS1979

The design and testing of a memory metal actuated boom release mechanism

A boom latch and release mechanism was designed, manufactured and tested, based on a specification for the ISEE-B satellite mechanism. From experimental results obtained, it is possible to calculate the energy available and the operating torques which can be achieved from a torsional shape memory element in terms of the reversible strain induced by prior working. Some guidelines to be followed when designing mechanisms actuated by shape memory elements are included.

Powley, D. G.↗
NASA NTRS1979

Compositions of energetic particle populations in interplanetary space

Observations of helium and heavier particles with energies below about 10 to 20 MeV/nucleon are discussed with emphasis on the composition of solar flare particles, corotating energetic particle streams, and the anomalous cosmic ray component. Future advances expected from results obtained from ISEE -3, Voyager, and the international solar polar spacecraft are reviewed.

Gloeckler, G.↗
NASA NTRS1978

Energetic plasma ions within the earth's magnetosheath

Observations in the dawn magnetosheath with the LASL/MPI fast plasma experiment on ISEE 1 and 2 reveal the existence of two distinct states of plasma flow within the sheath: a quiet state and a disturbed state. Energetic ions in the range of 3-40 keV are the distinguishing feature of the disturbed state. Long period (about 1 min) fluctuations in plasma density, temperature, flow speed, and flow direction occur simultaneously with the appearance of these high-energy particles. The most likely explanation of these observations is that the energetic ions are produced in the vicinity of the bow shock under certain (unspecified) interplanetary conditions, and that the fluctuations in plasma flow are produced locally by the interaction of the energetic ions with the ambient plasma.

Asbridge, J. R.↗
NASA NTRS1978

Observations of two distinct populations of bow shock ions in the upstream solar wind

Observations upstream of the earth's bow shock with the LASL/MPI fast plasma experiments on ISEE 1 and 2 reveal the presence of two distinct and mutually exclusive populations of low energy (no more than 40 keV) ions apparently accelerated at the bow shock. The first of these, the 'reflected' population, is characterized by (1) sharply peaked spectra seldom extending much above about 10 keV/ion and (2) relatively collimated flow coming from the direction of the shock. On the other hand, the 'diffuse' ions are distinguished by relatively flat energy spectra above about 10 keV and broad angular distributions. They are by far the most commonly observed upstream ion event. A close causal association is suggested between the diffuse ion population in the upstream solar wind and energetic plasma ions observed within the magnetosheath.

Gosling, J. T.↗
NASA NTRS1978

Evidence for solar wind origin of energetic heavy ions in the earth's radiation belt

Analysis of data from our energetic ion composition experiment on ISEE-1 has revealed the presence of substantial fluxes of carbon, oxygen, and heavier ions above 400 keV/nucleon at L values between approximately 2.5 and 4 earth radii. The measured C/O ratio varies systematically from 1.3 at 450 keV/nucleon to 4.1 at 1.3 MeV/nucleon, and no iron is observed above 200 keV/nucleon. These results provide strong evidence for a solar wind origin for energetic ions in the outer radiation belt. The absence of iron and the increase of the carbon-to-oxygen ratio with energy suggest that the condition for the validity of the first adiabatic invariant may have a strong influence on the trapping of these particles.

Hovestadt, D.↗