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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 433 records · Page 24
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NASA NTRS1990

Earth observations during Space Shuttle mission STS-30

The earth observations that were conducted during the STS-30 mission in May, 1989 are examined. An overview of the STS-30 mission is given, noting the launch of the Magellan spacecraft. The major positions of STS-30 photographs are illustrated and the sun elevation angles of the photographs and the types of films used during the mission are listed. Photographs of various regions are described, focusing on North Africa and the Middle East, South and Southeast Asia, Central America, the Caribbean, and the Southern U.S. The use of the photographs for various research purposes is discussed, including oceanography, meteorology, and polarization experiments. Also, consideration is given to the use of video/camcorders for earth observations.

Helfert, Michael R.↗
NASA NTRS1990

The distribution of middle tropospheric carbon monoxide during early October 1984

The measurement of Air Pollution from Satellite experiment measured the distribution of middle-tropospheric CO from the Space Shuttle during October 1984. The data represent average mixing ratios between 57 deg N and 57 deg S. Approximately 75,000 individual CO measurements were obtained during the 9-day mission. The data are presented in maps that show the CO mixing ratios averaged over 5 x 5-deg areas for 6 days of the mission. Comparisons with concurrent direct measurements taken aboard aircraft show that the inferred concentrations are systematically low by 20-40 percent, depending upon which direct measurement calibration standard is used. The data show that there are very large CO sources resulting from biomass burning over South America and southern Africa. Measured mixing ratios were high over northeast Asia and were highly variable over Europe.

Reichle, Henry G., Jr.↗
NASA NTRS1990

Origin of low frequency (intraseasonal) oscillations in the tropical atmosphere. III - Monsoon dynamics

The issue of the interaction of the monsoon large-scale circulation and intraseasonal oscillations is addressed, showing that, as a result of the interaction of the large scale monsoon flow with the near-equatorial intraseasonal oscillation, unstable baroclinic disturbances are generated over the monsoon region. From a linear stability analysis of quasi-geostrophic motion in a two-level model, it is shown that the westward propagating disturbances generated over the monsoon region are the manifestation of heat-induced unstable Rossby waves. The instability is favored in the region with large vertical wind shear and reduced effective static stability. The monsoon large scale circulation over India and southeast Asia and the plentiful supply of moisture in the region appear to be favorable for the development of these unstable waves.

Lau, K.-M.↗
NASA NTRS1990

Global-scale, intraseasonal fluctuations of diabatic forcing of the atmosphere

Fields of diabatic heating rate estimates (H) for 5-day periods were calculated from the European Center for Medium Weather Forecasts (ECMWF) analyses since 1985 as the residual of the dry thermodynamic equation. Included in these fields are the horizontal and vertical divergences of heat for both mean and eddy statistics. Previous work dealt with 4-day periods, however, with the emphasis in the Global Precipitation Climatology Project (GPCP) for 5-day period totals the change was made to accommodate the GPCP product. H has long been associated with cold tropical cloud-top temperatures as measured by polar orbiting outgoing longwave radiation (OLR) sensors. Correlations between H and OLR fields on three time scales indicate a moderate amount of agreement. For periods less than 90 days, significant negative correlations are found between H and OLR for (1) tropical and NH midlatitude oceanic areas, and (2) for zonal and hemispheric mean values. Positive correlations are seen in NH mean and continental areas of N. Africa, N. America, N. Asia and Antarctica. These latter results reflect seasonal heating and cooling. Comparisons have been made between H as H as calculated from the ECMWF analyses and output from the CCM1 T42 simulations. The CCM1 tends to have a more cellular structure with more heating (precipitation) over land versus that observed (ECMWF) over oceans.

Christy, John R.↗
NASA NTRS1990

Signs of interaction of the NGC 1275 nucleus with the high-velocity system according to 0.7 sec seeing observations

The nucleus of the Seyfert galaxy NGC 1275 was observed in the B system on 1 December 1989 with seeing 0, 7 seconds using the Zeiss-1000 telescope on Mount Majdanak in Central Asia. Special methods of processing reveal low-contrast details. The nucleus and circumnucleus are stretched in NW-SE direction. There are two narrow filaments near the nucleus in position angles roughly 340 degrees and 320 degrees. The first is directed near the radio jet of the nucleus, the second has broken details curved to the NW or toward the high-velocity system of NGC 1275.

Dudinov, V. N.↗
NASA NTRS1991

Research in geosciences policy

Various topics related to cases of difficult adaptation to global change are discussed. Topics include patterns in the ratification of global environmental treaties, the effects of global climate change on Southeast Asia, and global change and biodiversity loss.

Byerly, Radford, Jr.↗
NASA NTRS1990

Earth observations during Space Shuttle Mission STS-33 - November 23-27, 1989

An overview is presented of photographs, astronaut impressions, and photographic equipment and techniques coincident with the Discovery STS-33 mission of November 23-27, 1989. Particularly significant geographical photographs of southern Africa, Madagascar, northern Africa, Southeast Asia islands, Pacific islands, and Australia are shown and reviewed. Meteorological and oceanographic observations are summarized along with film anomalies that occurred during this mission.

Amsbury, David L.↗
NASA NTRS1991

A study of the sources and sinks of methane and methyl chloroform using a global three-dimensional Lagrangian tropospheric tracer transport model

Sources and sinks of methane and methyl chloroform are investigated using a global three-dimensional Lagrangian tropospheric tracer transport model with parameterized hydroxyl and temperature fields. Using the hydroxyl radical field calibrated to the methyl chloroform observations, the globally averaged release of methane and its spatial and temporal distribution were investigated. Two source function models of the spatial and temporal distribution of the flux of methane to the atmosphere were developed. The first model was based on the assumption that methane is emitted as a proportion of net primary productivity (NPP). The second model identified source regions for methane from rice paddies, wetlands, enteric fermentation, termites, and biomass burning based on high-resolution land use data. The most significant difference between the two models were predictions of methane fluxes over China and South East Asia, the location of most of the world's rice paddies, indicating that either the assumption that a uniform fraction of NPP is converted to methane is not valid for rice paddies, or that NPP is underestimated for rice paddies, or that present methane emission estimates from rice paddies are too high.

Taylor, John A.↗
NASA NTRS1991

Diabatic heating rate estimates from European Centre for Medium-Range Weather Forecasts analyses

Vertically integrated diabatic heating rate estimates (H) calculated from 32 months of European Center for Medium-Range Weather Forecasts daily analyses (May 1985-December 1987) are determined as residuals of the thermodynamic equation in pressure coordinates. Values for global, hemispheric, zonal, and grid point H are given as they vary over the time period examined. The distribution of H is compared with previous results and with outgoing longwave radiation (OLR) measurements. The most significant negative correlations between H and OLR occur for (1) tropical and Northern-Hemisphere mid-latitude oceanic areas and (2) zonal and hemispheric mean values for periods less than 90 days. Largest positive correlations are seen in periods greater than 90 days for the Northern Hemispheric mean and continental areas of North Africa, North America, northern Asia, and Antarctica. The physical basis for these relationships is discussed. An interyear comparison between 1986 and 1987 reveals the ENSO signal.

Christy, John R.↗
NASA NTRS1992

Gravity and the geoid in the Nepal Himalaya

Materials within the Himalaya are rising due to convergence between India and Asia. If the rate of erosion is comparable to the rate of uplift, the mean surface elevation will remain constant. Any slight imbalance in these two processes will lead to growth or attrition of the Himalaya. Although buried rocks, minerals and surface control points in the Himalaya are undoubtably rising, the growth or collapse or the Himalaya depends on the erosion rate which is invisible to geodetic measurements. A way to measure erosion rate is to measure the rate of change of gravity in a region of uplift. Essentially gravity should change precisely in accord with a change in elevation of the point in a free air gradient if erosion equals uplift rate. A measurement of absolute gravity was made simultaneously with measurements of GPS height within the Himalaya. Absolute gravity is estimated from the change in velocity per unit distance of a falling corner cube in a vacuum. Time is measured with an atomic clock and the unit distance corresponds to the wavelength of an iodine stabilized laser. An experiment undertaken in the Himalaya in 1991 provide a site description also with a instrument description.

Bilham, Roger↗
NASA NTRS1990

LOOPUS Mob-D: System concept for a public mobile satellite system providing integrated digital services for the Northern Hemisphere from an elliptical orbit

A new concept for a satellite based public mobile communications system, LOOPUS Mob-D, is introduced, whereby most of the classical problems in mobile satellite systems are approached in a different way. The LOOPUS system will offer a total capacity of 6000 high rate channels in three service areas (Europe, Asia, and North America), covering the entire Northern Hemisphere with a set of group special mobile (GSM) compatible mobile services, eventually providing the 'office in the car'. Special characteristics of the LOOPUS orbit and the communications network architecture are highlighted.

Kuhlen, H.↗
NASA NTRS1992

Report on the international Cambodian crater expedition, 1992

It has been proposed that Tonle Sap, a lake in Cambodia, 100 km long and 30 km wide, marks the location of an elongate basin formed by the oblique impact of a comet or asteroid. The impact is considered to have produced melted ejecta found now as tektites over much of southeast Asia and Australia. The location of the lake, its approximate age, its size, and the orientation of its long axis (toward Australia) are consistent with this hypothesis. Our scientific objectives were to find impact or shock metamorphosed rocks unambiguously related to the Tonle Sap basin, to collect samples of rocks that may represent those melted to produce Australasian tektites, and to learn as much as possible about Cambodian geology. Using 1:200,000-scale geologic maps with fairly detailed descriptions of the rock units, we selected a number of acceptable 'phnoms' (hills that rise abruptly out of the surrounding plain) that may contain rocks affected by the postulated Tonle Sap impact. A map of central Cambodia is shown, and the locations of sites where samples were collected are indicated. A list of those sites, together with a description of the rocks reported to be present at each site, is given. No obviously shock-metamorphosed or suevite-like rocks were observed. Recent alluvium surrounding Tonle Sap is judged to be lake sediment deposited when the lake surface was at a higher elevation.

Hartung, J.↗
NASA NTRS1992

Tesseract: Supersonic business transport

This year, the senior level Aerospace Design class at Case Western Reserve University developed a conceptual design of a supersonic business transport. Due to the growing trade between Asia and the United States, a transpacific range has been chosen for the aircraft. A Mach number of 2.2 was chosen too because it provides reasonable block times and allows the use of a large range of materials without a need for active cooling. A payload of 2500 lbs. has been assumed corresponding to a complement of nine (passengers and crew) plus some light cargo. With these general requirements set, the class was broken down into three groups. The aerodynamics of the aircraft were the responsibility of the first group. The second developed the propulsion system. The efforts of both the aerodynamics and propulsion groups were monitored and reviewed for weight considerations and structural feasibility by the third group. Integration of the design required considerable interaction between the groups in the final stages. The fuselage length of the final conceptual design was 107.0 ft. while the diameter of the fuselage was 7.6 ft. The delta wing design consisted of an aspect ratio of 1.9 with a wing span of 47.75 ft and midcord length of 61.0 ft. A SNEMCA MCV 99 variable-cycle engine design was chosen for this aircraft.

Reshotko, Eli↗
NASA NTRS1992

Asteroids with unusual lightcurves: 14 Irene and 51 Nemausa

Some asteroids with peculiar light curves were chosen for more detail investigation. We present the first results of that study. Observations were obtained in 1989 and 1990 using the 70-cm telescope of Kharkov Observatory; the 40-cm telescope of Abastumani Observatory (Georgia), and the 60-cm telescope of the Main Astronomical Observatory of Ukrainian Academy of Sciences (Mt. Majdanak, Middle Asia). Observations and their reduction were carried out in a standard way. The aspect data, absolute magnitude of primary maximum, and lightcurve amplitude are given.

Belskaya, I. N.↗
NASA NTRS1992

ETS-5, ETS-6, and COMETS projects in Japan

Three satellite communication projects now in progress in Japan are described. The first is a project to establish a telecommunication network for tele-education, TV conference, and tele-medicine in the Asia-Pacific region by using the Japan's Engineering Test Satellite-5 (ETS-5). The second is a project of the ETS-6 satellite, to be launched in 1993, for inter-satellite communication, mobile and fixed communication, and millimeter wave personal communication experiments. The third is a project of the Communications and Broadcasting Engineering Test Satellite (COMETS), to be launched in 1997, for advanced mobile satellite communication, inter-satellite link, and advanced broadcasting experiments at higher frequencies.

Iida, Takashi↗
NASA NTRS1992

Satellite communications application to Pacific countries above Ku band

An application of satellite communications above the Ku band to the Pacific region is described, focusing on: (1) Lightsat system and (2) a high capacity satellite system. A small geostationary satellite system using Ku band for the Federated States of Micronesia is shown as an example. A concept of multi-gigabits/second high capacity communications system using two satellites in the Ka band is described. The onboard bit-by-bit processing is very useful in the low link margin environment due to rain attenuation. These topics were obtained by the Asia Pacific Telecommunications Study granted by NASA conducted by the University of Colorado at Boulder.

Iida, Takashi↗
NASA NTRS1992

The Moho as a magnetic boundary revisited

Approximately 400 globally distributed xenolith samples are examined to determine whether continental regions are characterized by relatively magnetic crusts lying on relatively nonmagnetic mantles. Samples of mantle peridotites and mafic granulites by Wasilewski et al. (1979) are supplemented by samples of mantle and crustal xenoliths from Asia, North America, Africa, and Antarctica. The data indicate that a magnetic crustal layer overlies a nonmagnetic mantle much in the same manner as proposed by Jarchow and Thompson (1989). Nonmagnetic chrome spinels and magnesian ilmenites make up the ultramafic upper-mantle xenolith suite. Mafic rocks are the typically magnetic components of the crust, and induced magnetizations can account for long-wavelength magnetic anomalies measured remotely by aircraft and spacecraft.

Wasilewski, P. J.↗
NASA NTRS1993

Gravity field over northern Eurasia and variations in the strength of the upper mantle

The correlation of long-wavelength gravity anomalies in northern Eurasia with seismic velocity anomalies in the upper mantle reverses in sign between western and eastern Eurasia. The difference between western and eastern Eurasia can be explained by the presence of a low-viscosity zone in the uppermost mantle beneath eastern Eurasia that is absent to the west. The location of the lateral change in viscosity corresponds with the geologic boundary between the older shields and platforms of the Baltics, Russia, and Siberia and the younger, geologically active mountain belts of eastern Asia. This relation provides evidence that differences in the strength of the upper mantle control the locus of intracontinental deformation.

Kogan, Mikhail G.↗