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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 1,207 records · Page 67
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Photovoltaic power system for satellite Earth stations in remote areas: Project status and design description

A photovoltaic power system which will be installed at a remote location in Indonesia to provide power for a satellite Earth station and a classroom for video and audio teleconferences are described. The Earth station may also provide telephone service to a nearby village. The use of satellite communications for development assistance applications and the suitability of a hybrid photovoltaic engine generator power system for remote satellite Earth stations are demonstrated. The Indonesian rural satellite project is discussed and the photovoltaic power system is described.

Delombard, R.↗
NASA NTRS1977

Earth orbital assessment of solar electric and solar sail propulsion systems

The earth orbital applications potential of Solar Electric (Ion Drive) and Solar Sail low-thrust propulsion systems are evaluated. Emphasis is placed on mission application in the 1980s. The two low-thrust systems are compared with each other and with two chemical propulsion Shuttle upper stages (the IUS and SSUS) expected to be available in the 1980s. The results indicate limited Earth orbital application potential for the low-thrust systems in the 1980s (primarily due to cost disadvantages). The longer term potential is viewed as more promising. Of the two systems, the Ion Drive exhibits better performance and appears to have better overall application potential.

Teeter, R. R.↗
NASA NTRS1972

Gegenschein-Moulton region photography from lunar orbit

Apollo 16 photography during lunar orbit of the Gegenschein-Moulton region was used to determine the libration points of the Sun-Earth system. Triangulation for the system is discussed, along with background experimental information.

Dunkelman, L.↗
NASA NTRS1972

Virginia precipitation scatter experiment: Experiment description

A year's statistical data were acquired for the purposed of refining existing coordination procedures for the sharing of common frequency allocations between terrestrial and space services. The measurement program was conducted between October 3, 1970 and October 2, 1971, to empirically determine the cumulative distributions of scattering cross section per unit volume of hydrometeors at heights up to 9 km above the surface and of rain rate at the surface. The measurements were made in southeastern Virginia using a bistatic, continuous-wave, vertically polarized radar system operating at S- and X-band frequencies and tipping-bucket rain gages. The bistatic radar system was configured to represent an interference situation between a radio-relay system and a space communication system Earth terminal; the results may be interpreted as measured distributions of transmission loss for interference due to rain. A description of the experiment and equipment is included.

Levine, E.↗
NASA NTRS1978

Determination of the ozone profile from the outgoing thermal emission

Problems of the information content of measuring the spectral and angular distribution of the outgoing thermal emission of the atmosphere-earth system in the 9.6 mm ozone absorption band are discussed. Two methods (nadir and limb) of remote measurement are considered. Information data obtained are evaluated according to three systems. Effectiveness of the regression interpretation method using the data of nadir and limb measurements is shown.

Borisenkov, Y. P.↗
NASA NTRS1980

Analytic construction of periodic orbits about the collinear points

A third-order analytical solution for halo-type periodic motion about the collinear points of the circular-restricted problem is presented. The three-dimensional equations of motion are obtained by a Lagrangian formulation. The solution is constructed using the method of successive approximations in conjunction with a technique similar to the Lindstedt-Poincare method. The theory is applied to the sun-earth system.

Richardson, D. L.↗
NASA NTRS1980

Open-loop nanosecond-synchronization for wideband satellite communications

A synchronization technique for use with an onboard processing satellite communication system is discussed. The satellite oscillator is used both as the system time reference and as the frequency source for all downlink carriers and data clocks. Downlink timing is established at each system earth terminal through a combination of carrier and data-clock tracking and a downlink timing epoch signal consisting of one bit per TDMA data burst. Uplink timing is established by an open-loop range prediction process using precision ephemerides calculated and distributed by the central control station. Overall timing accuracy of the uplink signal at the satellite receiver of + or - 7 nanoseconds permits unambiguous identification of each data bit position in a 128 Mbps TDMA burst. This is accomplished by means of simple, inexpensive terminal hardware using available crystal oscillators for time/frequency references and digital synthesis techniques that may be implemented in digital LSI chips.

Holmes, W. M., Jr.↗
NASA NTRS1985

The coorbital hypothesis

Voyager I and II have revealed the existence of 1980S1 and 1980S3 in the same orbit that add to the discovery of the Lagrange satellite 1980S6 for Dione and 1980S13 - 1980S25 for Thetys as a replica to the Trojan planets in the Jupiter orbit. These bodies may issue from the rupture of a primitive gaseous ring through a disturbance. The Lagrange figures keep stable while the rest of the objects drift in near paths and interact at each transit so as to form a gradual binary. The Moon - Earth system may have a such origin.

Andlauer, G.↗
NASA NTRS1986

Earth observations in the twenty-first century

Some of the achievements of earth observations from past space missions are described. Also discussed are the achievements to be anticipated from currently approved and planned earth observation missions. In looking forward to what the objectives of earth observations from space are expected to be in the future, together with what technology is expected to enable, what the earth observing program will look like during the first part of the twenty-first century is discussed. It is concluded that a key part of this program will be long-term observations holistically viewing the earth system.

Geller, M. A.↗
NASA NTRS1987

The Spaceborne Imaging Radar program: SIR-C - The next step toward EOS

The NASA Shuttle Imaging Radar SIR-C experiments will investigate earth surface and environment phenomena to deepen understanding of terra firma, biosphere, hydrosphere, cryosphere, and atmosphere components of the earth system, capitalizing on the observational capabilities of orbiting multiparameter radar sensors alone or in combination with other sensors. The SIR-C sensor encompasses an antenna array, an exciter, receivers, a data-handling network, and the ground SAR processor. It will be possible to steer the antenna beam electronically, so that the radar look angle can be varied.

Evans, Diane↗
NASA NTRS1988

Outer atmospheric research

The region above the earth from about 90 km to 150 km is a major part of the upper or outer atmosphere. It is relatively unexplored, being too high for balloons or aircraft and too low for persistent orbiting spacecraft. However, the concept of a tethered subsatellite, deployed downward from an orbiting, more massive craft such as the Space Shuttle, opens the possibility of a research capability that could provide global mapping of this region. The need for research in this thick spherical shell above the earth falls into two major categories: (1) scientific data for understanding and modeling the global atmosphere and thereby determining its role in the earth system, and (2) engineering data for the design of future aerospace vehicles that will operate there. This paper presents an overview and synthesis of the currently perceived research needs and the state-of-the-art of the proposed tethered research capability.

Anderson, John L.↗
NASA NTRS1988

Toward an understanding of global change: Initial priorities for US contributions to the International Geosphere-Biosphere Program

A limited number of high-priority research initiatives are recommended for early implementation as part of the U.S. contribution to the preparatory phase of the International Geosphere-Biosphere Program. The recommendations are based on the committee's analysis of the most critical gaps in the scientific knowledge needed to understand the changes that are occurring in the earth system not being addressed by existing programs. The report articulates a number of important key issues and interactions that characterize global change in the geosphere-biosphere system on time scales of decades to centuries; identifies the knowledge that is the most urgently needed to improve understanding of those issues and interactions; and formulates initial priorities for initial U.S. contributions to the IGBP, recognizing the contributions of other ongoing and proposed programs.

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NASA NTRS1990

An algorithm for retrieving water vapor profiles in clear and cloudy atmospheres from 183 GHz radiometric measurements - Simulation studies

The latent heat represented by atmospheric water vapor is extremely important to the energetics of the earth system. Future satellites (NOAA and DMSP) will carry microwave radiometers designed to measure the profile of water vapor globally. The problem of retrieving water vapor from the measurements is highly nonlinear even in clear atmospheres and the addition of clouds only makes it more so. In this paper, an algorithm with several novel features, which will retrieve water vapor profiles from microwave radiometric measurements even in the presence of clouds, is developed. Simulations with this algorithm show a vertical resolution on the order of 3 km and that clouds are well handled in many, but not all, circumstances. The most surprising result is that clouds can actually improve the vertical resolution of the retrieval.

Wilheit, Thomas T.↗
NASA NTRS1991

Global water cycle

The primary objective is to determine the scope and interactions of the global water cycle with all components of the Earth system and to understand how it stimulates and regulates changes on both global and regional scales. The following subject areas are covered: (1) water vapor variability; (2) multi-phase water analysis; (3) diabatic heating; (4) MSU (Microwave Sounding Unit) temperature analysis; (5) Optimal precipitation and streamflow analysis; (6) CCM (Community Climate Model) hydrological cycle; (7) CCM1 climate sensitivity to lower boundary forcing; and (8) mesoscale modeling of atmosphere/surface interaction.

Robertson, Franklin R.↗
NASA NTRS1991

Monitoring, analyzing, and modeling global climate

Diabatic heating rate estimates as residuals of the dry thermodynamic equation were generated for May 1, 1985 to December 1989 in pentad resolution. Published results show moderate correlations (approx. .6) between heating rate and outgoing long wave radiation for periods under 90 days in the tropics and many extratropical locations. Nine years of simulation with the Community Climate Model 1 (CCM1) using R15 and observed sea surface temperatures shows that the model retains significantly more heat at the surface and in the free atmosphere than does the actual earth system. A post-processor for the CCM1, with capabilities to produce simulated microwave sounding unit (MSU) brightness temperatures was written. Techniques were refined considerably and validation studies were carried out to verify the globally distributed free atmosphere temperature anomalies derived from MSU data. The precision is such that detailed, long-term climate monitoring is well within the capability of these data.

Christy, John R.↗
NASA NTRS1992

Our Changing Planet: The FY 1993 US Global Change Research Program. A report by the Committee on Earth and Environmental Sciences, a supplement to the US President's fiscal year 1993 budget

The U.S. Global Change Reasearch Program (USGCRP) was established as a Presidential initiative in the FY-1990 Budget to help develop sound national and international policies related to global environmental issues, particularly global climate change. The USGCRP is implemented through a priority-driven scientific research agenda that is designed to be integrated, comprehensive, and multidisciplinary. It is designed explicitly to address scientific uncertainties in such areas as climate change, ozone depletion, changes in terrestrial and marine productivity, global water and energy cycles, sea level changes, the impact of global changes on human health and activities, and the impact of anthropogenic activities on the Earth system. The USGCRP addresses three parallel but interconnected streams of activity: documenting global change (observations); enhancing understanding of key processes (process research); and predicting global and regional environmental change (integrated modeling and prediction).

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NASA NTRS1992

Ionizing radiation environment for the TOMS mission

The Total Ozone Mapping Spectrometer (TOMS) will fly on several different spacecraft, each having an orbit which is approximately polar and 800-980 km in altitude. A description is given of the computer-based tools used for characterizing the spacecraft interactions with the ionizing radiation environment in orbit and the susceptibility requirements for ionizing radiation compatibility. The peak flux from the model was used to derive the expected radiation-induced noise in the South Atlantic Anomaly for the new TOMS instruments intended to fly on Advanced Earth Observatory System and Earth Probe.

Lauriente, M.↗