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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 1,153 records · Page 64

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NASA NTRS1978

Partitioning of Ni/2+/ between basaltic and synthetic melts and olivines An experimental study

Olivine/liquid distribution coefficients for Ni in basaltic and simple synthetic melts are found in the 1400-1070 C temperature range. The results suggest that: (1) the Ni distribution coefficients and NiO activity coefficients are strongly temperature dependent, (2) the Ni distribution coefficients are functions of melt composition and structure at a constant temperature although the dependence is small for most basaltic magmas, (3) differences in melt composition do not significantly influence generally 'basaltic' melts, (4) the Ni distribution coefficients may be used as geothermometers to predict the olivine crystallization temperatures of basaltic magmas to within plus or minus 50 C, (5) the Ni distribution coefficients are greater than one at all natural magmatic temperatures, and (6) the Ni distribution coefficients do not significantly vary as functions of the Ni content of the melt to at least one mole percent.

Leeman, W. P.↗

NASA NTRS1978

Synthesis of aircraft structures using integrated design and analysis methods

A systematic research is reported to develop and validate methods for structural sizing of an airframe designed with the use of composite materials and active controls. This research program includes procedures for computing aeroelastic loads, static and dynamic aeroelasticity, analysis and synthesis of active controls, and optimization techniques. Development of the methods is concerned with the most effective ways of integrating and sequencing the procedures in order to generate structural sizing and the associated active control system, which is optimal with respect to a given merit function constrained by strength and aeroelasticity requirements.

Sobieszczanski-Sobieski, J.↗

NASA NTRS1982

Description of the Deep Space Network

The facilities, functions, and operations capabilities of the Deep Space Network are summarized. Network activities in support of planned future as well as ongoing deep space missions are described as are activities in support of radio astronomy experiments and the Astronomical Radio Interferometric Earth Surveying (ARIES) Network.

Renzetti, N. A.↗

NASA NTRS1983

Handbook of photothermal test data on encapsulant materials

Laboratory tests performed to characterize candidate encapsulation materials with respect to changes in their physical and chemical properties caused by photothermal aging are described. Several key material properties relating directly to material degradation and deterioration of performance were identified and were monitored as functions of aging conditions and time. A status report on accelerated testing activities is provided and experimental data are presented. It will be updated periodically as more data become available.

Liang, R. H.↗

NASA NTRS1982

Alterations in mitochondria and sarcoplasmic reticulum from heart and skeletal muscle of horizontally casted primates

Horizontally body-casted rhesus monkeys are used as an animal model in order to study the physiological changes known as cardiovascular deconditioning which occur during weightless conditions. No difference was found between the experimental and control animals in heart mitochondrial oxidative phosphorylation which indicates that no apparent changes occurred in the primary energy-producing system of the heart. A marked increase in cytochrome oxidase activity was observed in the casted primate heart mitochondria compared to controls, while a 25% decrease in respiratory substrate-supported calcium uptake was found in casted primate heart mitochondria compared to controls. Sacroplasmic reticulum isolated from the primate hearts revealed marked changes in calcium transport activities. It is concluded that the marked depression in cardiac sarcoplasmic reticulum functions indicates altered calcium homeostasis in the casted-primate heart which could be a factor in cardiovascular deconditioning.

Sordahl, L. A.↗

NASA NTRS1983

Associations between coronal mass ejections and soft X-ray events

The association between white light coronal mass ejections (CMEs) and full-disk X ray events have been examined as a function of X ray duration during the recent years of high sunspot activity (1979-1981). On a time scale of hours, no duration interval has been found that separates X ray events into two distinct classes depending on whether or not they have associated CMEs. Rather, the tendency for long-duration X ray events to have associated CMEs reflects the fact that, as X ray duration increases, the differential distribution of events without CMEs falls off faster than the distriution of X ray events with CMEs.

Sheeley, N. R., Jr.↗

NASA NTRS1984

Space station automation study-satellite servicing, volume 2

Technology requirements for automated satellite servicing operations aboard the NASA space station were studied. The three major tasks addressed: (1) servicing requirements (satellite and space station elements) and the role of automation; (2) assessment of automation technology; and (3) conceptual design of servicing facilities on the space station. It is found that many servicing functions cloud benefit from automation support; and the certain research and development activities on automation technologies for servicing should start as soon as possible. Also, some advanced automation developments for orbital servicing could be effectively applied to U.S. industrial ground based operations.

Meissinger, H. F.↗

NASA NTRS1985

CNPq/INPE-LANDSAT system

The current status of the Brazilian LANDSAT facilities operated by Instituto de Pesquisas Espaciais (INPE) and the results achieved during the period from October 1, 1984 to August 31, 1985 are presented. INPE's Receiving Station at Cuiaba, MT, operates normally the two tracking and receiving systems it has installed, the old one (1973) for Band S and the new one (February 1983) for dual S- and X-band. Both MSS and TM recording capabilities are functional. Support to the NASA Backup Plan for MSS data also remains active. Routine recordings are being made for LANDSAT-5 only, for both MSS and TM. Originally, MSS was recorded over the full acquisition range. However, since December, 1984, due to further reduction of operational expenses, both instruments are being recorded over Brazilian territory only.

Debarrosaguirre, J. L.↗

NASA NTRS1986

Nitrogen uptake and utilization by intact plants

The results of experiments support the proposed conceptual model that relates nitrogen uptake activity by plants as a balanced interdependence between the carbon-supplying function of the shoot and the nitrogen-supplying function of the roots. The data are being used to modify a dynamic simulation of plant growth, which presently describes carbon flows through the plant, to describe nitrogen uptake and assimilation within the plant system. Although several models have been proposed to predict nitrogen uptake and partitioning, they emphasize root characteristics affecting nutrient uptake and relay on empirical methods to describe the relationship between nitrogen and carbon flows within the plant. Researchers, on the other hand, propose to continue to attempt a mechanistic solution in which the effects of environment on nitrogen (as well as carbon) assimilation are incorporated through their direct effects on photosynthesis, respiration, and aging processes.

Raper, C. D., Jr.↗

NASA NTRS1986

Measuring research progress in photovoltaics

The role and some results of the project analysis and integration function in the Flat-plate Solar Array (FSA) Project are presented. Activities included supporting the decision-making process, preparation of plans for project direction, setting goals for project activities, measuring progress within the project, and the development and maintenance of analytical models.

Jackson, B.↗

NASA NTRS1986

Active extragalactic sources - Nearly simultaneous observations from 20 centimeters to 1400 A

IRAS, IUE, and ground-based optical, NIR, mm and submm, and radio observations obtained mainly on Apr. 9-23, 1983, are reported for 19 active extragalactic sources and eight control sources. The overall spectra of the compact active sources are shown to be well represented by continuous-curvature functions such as parabolas. The spectra are found to be consistent with models involving continuous particle injection (with synchrotron losses) or first-order Fermi acceleration (with escape and synchrotron losses), but not with models using relativistic Maxwellian electron distributions.

Landau, R.↗

NASA NTRS1988

An investigation of conformable antennas for the astronaut backpack communication system

During periods of extravehicular activity it is obviously important that communication and telemetry systems continue to function independently of the astronaut. A system of antennas must therefore be designed that will provide the necessary isotropic coverage using circular polarization over both the transmit and receive frequency bands. To avoid the inherent physical limitations to motion that would be incurred with any sort of protruding antenna, it is necessary that the radiator be essentially flush-mounted or conformable to the structure on which it is attached. Several individual antenna elements are needed for the desired coverage. Both the particular elements chosen and their location determine the ultimate radiation pattern of the overall system. For these reasons a two-fold research plan was undertaken. First, individual elements were investigated and designed. Then various mounting locations were considered and the radiation patterns were predicted taking into account the effects of the astronaut's backpack.

Long, Stuart A.↗

NASA NTRS1988

Control of the induced microgravity environment of the Man Tended Free Flyer (MTFF)

Induced disturbance sources have been identified on board the Man Tended Free Flyer (MTFF). Vibration responses at sensitive payload/spacecraft interfaces have been predicted by the application of an empirically found spacecraft dynamic transfer function. Vibrations from fluid loops (Freon, water) and of reaction wheels are assessed to be the main contributors to the induced microgravity environment. The expected payload acceleration response amplitudes presented here are more than one hundred times higher than the admissible values given by the MTFF system requirement, not considering the structural striction-friction effects which could be avoided by appropriate design. Real responses will be significantly lower because the derivation of excitation and transmission functions are based on worst case assumptions. The results indicate that future activities must be concentrated on equipment design improvement and the implementation of vibration reduction along the disturbance transmission path. The activities must be accompanied by early equipment and assembly development tests and transmissibility measurements with the integrated spacecraft engineering and structural models in order to improve the accuracy of payload response predictions.

Schlund, Juergen↗

NASA NTRS1989

Theoretical investigations of the structures and binding energies of Be(sub n) and Mg(sub n) (n = 3-5) clusters

Researchers determined the equilibrium geometries and binding energies of Be and Mg trimers, tetramers and pentamers using single and double excitation coupled cluster (CCSD) and complete active space self-consistent-field (CASSCF) multireference configuration interaction (MRCI) wave functions in conjunction with extended atomic basis sets. Best estimates of the cluster binding energies are 24, 83 and 110 kcal/mole for Be3, Be4 and Be5; and 9, 31 and 41 kcal/mole for Mg3, Mg4 and Mg5, respectively. A comparison of the MRCI and CCSD results shows that even the best single-reference approach (limited to single and double excitations) is not capable of quantitative accuracy in determining the binding energies of Be and Mg clusters.

Lee, Timothy J.↗

NASA NTRS1990

Theoretical investigations of the structures and binding energies of Be(n) and Mg(n) (n = 3-5) clusters

The equilibrium geometries and binding energies of Be and Mg trimers, tetramers and pentamers have been determined using single and double excitation coupled cluster (CCSD) and complete active space self-consistent-field (CASSCF) multireference configuration interaction (MRCI) wave functions in conjunction with extended atomic basis sets. The best estimates of the cluster binding energies are 24, 83, and 110 kcal/mol for Be3, Be4, and Be5; and 9, 31, and 41 kcal/mol for Mg3, Mg4, and Mg5, respectively. A comparison of the MRCI and CCSD results shows that even the best single-reference approach (limited to single and double excitations) is not capable of quantitative accuracy in determining the binding energies of Be and Mg clusters.

Lee, Timothy J.↗

NASA NTRS1990

The systematic radial downflow in the transition region of the quiet sun from limb-to-limb observations of the C IV resonance lines

This paper presents absolute velocities of C IV 1548, 1550 nm measured as a function of position along the solar equator, which was free of both active regions and coronal holes, and uniformly representative of the quiet sun. These observations were made with moderate spatial resolution (18 arcsec) using an EUV spectrometer dedicated to measuring absolute wavelengths (velocities) by direct comparison with a platinum spectrum generated on board the sounding rocket. On the assumption that systematic horizontal motions cancel statistically so that the line-of-sight velocities approach zero at the limb, a net radial downflow of 7.5 + or - 1.0 km/sec was found. The assumption was tested using the wavelength reference and found to be valid within the absolute accuracy of the rest wavelengths of the C IV lines.

Rottman, Gary J.↗

NASA NTRS1991

The development of the EOS data and information system

The architecture of the Earth Observing System (EOS), a major component of NASA's contribution to the U.S. Global Change Research Program, is described with emphasis on its development strategy. It is noted that the EOS is comprised of a scientific research program, a space measurement system, and an EOS Data and Information System (EOSDIS). Details are presented concerning the EOS program and its candidate instruments. Major components of EOS include Version 0 (V0) built on existing Distributed Active Archive Centers (DAACs), the EOSDIS core system (ECS), DAAC-unique functions, science computing facilities (SCF), and independent verification validation of the ECS. Requirements for EODIS are also reviewed noting that, among other requirements, it must keep up with an orbital average data rate of more than 30 Mbps as well as store, distribute, and manage information about tens of Petabytes of data during and after the 15-year mission.

Taylor, Thomas D.↗

NASA NTRS1990

The Cambridge encyclopedia of space (revised edition)

A comprehensive and intensively illustrated development history is presented for spaceflight, ranging over its basic concepts' speculative and fictional origins, the historical roots of rocket-related technologies, and the scientific accomplishments of earth orbit and interplanetary missions to date. Attention is given to propulsion systems, spaceflight launch centers, satellite systems, and solar system exploration by the U.S. and the Soviet Union. Current space-related activities encompass the meteorology, remote sensing, telecommunications and direct broadcasting, and navigation functions of unmanned satellites, as well as such manned spacecraft roles as medical and materials science research. The military uses of space, and increasingly important space industrialization concepts, are discussed as well.

D'Allest, Frederic↗