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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Project Intelsat 5

With 12,000 voice circuits and 2 television channels, intelsat 5, the first of a new generation of international telecommunication satellites, has almost double the communication capability of early satellites in the series. The 1,928 kilogram (at a lunch) satellite will be placed into geosynchronous orbit over the Atlantic Ocean to provide communications between North America and Europe. The characteristics of the Atlas Centaur launch vehicle to be used are described and the flights events of the launch sequence are tabulated.

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NASA NTRS1980

World weather program

A brief description of the Global Weather Experiment is presented. The world weather watch program plan is described and includes a global observing system, a global data processing system, a global telecommunication system, and a voluntary cooperation program. A summary of Federal Agency plans and programs to meet the challenges of international meteorology for the two year period, FY 1980-1981, is presented.

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NASA NTRS1981

Market capture by 30/20 GHz satellite systems, volume 2

Results of a telecommunications demand study are presented. Forecasts of demand for 30/20 GHz satellite systems, and the expected build up of traffic on these systems are given as a function of time for each of several operational scenarios.

Gamble, R. B.↗
NASA NTRS1981

ISPM X-band uplink technology demonstration. Part 1: Overview

The ground and spacecraft hardware research, design, and implementation lead to an end to end in flight technology demonstration on the International Solar Polar Mission spacecraft. An introduction to the overall effort is given and the flight experiment objectives are established. The expected improvements in the telecommunications performance are summarized. Also presented is a conceptual mission operations plant.

Komarek, T. A.↗
NASA NTRS1981

Two-way sequential time synchronization: Preliminary results from the SIRIO-1 experiment

A two-way time synchronization experiment performed in the spring of 1979 and 1980 via the Italian SIRIO-1 experimental telecommunications satellite is described. The experiment was designed and implemented to precisely monitor the satellite motion and to evaluate the possibility of performing a high precision, two-way time synchronization using a single communication channel, time-shared between the participating sites. Results show that the precision of the time synchronization is between 1 and 5 ns, while the evaluation and correction of the satellite motion effect was performed with an accuracy of a few nanoseconds or better over a time interval from 1 up to 20 seconds.

Detoma, E.↗
NASA NTRS1981

Networks and external sources of information, section 12

The basic functional aspects of telecommunications, text searching, and networking are reviewed. Some of the information services, both commercial and noncommercial, which are operational in the United States and Europe are described. The ARPANET, TELENET, TYMET, and EURONET packet networks are described. External online bibliographic data bases and factual data banks are reviewed. Details of services offered, specific topics available, and contact points are given for: (in the United States) the NASA/RECON, DOE/RECON, Defense RDT and E, Lockheed Information System (DIALOG), SDC ORBIT, and the bibliograhic Retrieval systems; and (in Europe), ESA/IRS, the International Atomic Energy Agency, TELESYSTEMS, SPIDEL, INKA DIMDI DATA-STAR, BLAISE, and PERGAMON-INFOLINE systems.

Eckert, P. F.↗
NASA NTRS1981

Highlights of NASA/DOE photovoltaic market assessment visit to Morocco

A broad range of agricultural, rural development, and other power applications in various regions of Morocco were examined to determine the potential market for photovoltaic products in Moroccan development. The primary focus of the study was the agriculture sector which accounts for approximately 17% of the country's GNP. The country has a clear need for reliable remote power systems, but does not have the financial resources to invest in the relatively high capital cost PV equipment. A modest potential for PV use was identified in nonagricultural rural services, such as refrigerators for rural clinics and rural radio-telephones. The main potential for PV in Morocco in the next five years lies mainly in the telecommunications sector. Applications include rural TV sets, TV repeater stations, microwave relay stations, and railroad, marine, and airline signalling. Market size estimates were derived from development and expansion plans. At an average customer cost for complete installed systems from $18/Wp to $30/Wp the total potential market value is estimated in the range of $6.6 to $11 million over the 1981-1986 period.

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NASA NTRS1981

Microwave noise temperature and attenuation of clouds at frequencies below 50 GHz

The microwave attenuation and noise temperature effects of clouds can result in serious degradation of telecommunications link performance, especially for low-noise systems presently used in deep-space communications. Although cloud effects are generally less than rain effects, the frequent presence of clouds will cause some amount of link degradation a large portion of the time. Cloud types, water particle densities, radiative transfer, attenuation and noise temperature calculations are reviewed and examples of basic link signal to noise ratio calculations are given. Calculations for twelve different cloud models are presented for frequencies of from 1 to 50 GHz and elevation angles of 30 degrees and 90 degrees. These case results may be used as a handbook to predict noise temperature and attenuation values for known or forecast cloud conditions.

Slobin, S. D.↗
NASA NTRS1981

Publications of the Jet Propulsion Laboratory, 1980

This bibliography cites by primary author the externally distributed technical reporting, released during calendar year 1980, that resulted from scientific and engineering work performed, or managed, by the Jet Propulsion Laboratory. Three classes of publications are included: (1) JPL Publications (77-, 78-, 79-series, etc.), in which the information is complete for a specific accomplishment and can e tailored to wide or limited audiences and be presented in an established standard format or special format to meet unique requirements; (2) articles published in the open literature; and (3) articles from the bimonthly Deep Space Network (DSN) Progress Repot (42-series) and its successor, the Telecommunications and Data Acquisition (TDA) Progress Report (also 42-series).

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NASA NTRS1981

The effects of receiver tracking phase error on the performance of the concatenated Reed-Solomon/Viterbi channel coding system

Analytical and experimental results are presented of the effects of receiver tracking phase error, caused by weak signal conditions on either the uplink or the downlink or both, on the performance of the concatenated Reed-Solomon (RS) Viterbi channel coding system. The test results were obtained under an emulated S band uplink and X band downlink, two way space communication channel in the telecommunication development laboratory of JPL with data rates ranging from 4 kHz to 20 kHz. It is shown that, with ideal interleaving, the concatenated RS/Viterbi coding system is capable of yielding large coding gains at very low bit error probabilities over the Viterbi decoded convolutional only coding system. Results on the effects of receiver tracking phase errors on the performance of the concatenated coding system with antenna array combining are included.

Liu, K. Y.↗
NASA NTRS1981

The development of future lunar exploration

Selected aspects of the eventual development of lunar exploration leading to the establishment of a human outpost on the moon are discussed. Possible means of spacecraft propulsion and guidance on an earth-moon trajectory are examined, together with likely means of telecommunications, including by laser and lunar-orbiting communications satellites. As yet unexploited orbits in the earth-moon system are pointed out, and the necessity for the increased use of computerized robots for surface navigation is discussed. Favorable locations for a habitat site, particularly the lunar poles are also considered. Implications of the availability of extraterrestrial resources for materials processing techniques and food production in the lunar environment are then indicated.

Burke, J. D.↗
NASA NTRS1981

Spectrum allocations above 40 GHz

The 1979 World Administrative Radio Conference (WARC-79) revised the International Table of Frequency Allocations to reflect increased interest and activity in the region of the EM spectrum above 40 GHz. The total width of the spectrum allocated (235 GHz) in the region above 40 GHz indicates the extent of this new spectrum resource, made accessible by advances in the state-of-the-art of telecommunications equipment. There are some striking differences between the approach to allocation above and below 40 GHz. For example, there are not bands allocated exclusively. This reflects the characteristics of propagation and the small antenna beamwidths achievable at these frequencies. Attention is given to atmospheric window and absorption band limits, allocations to satellite services, allocations to scientific services, allocations to terrestrial services, the future refinement of the radio regulations above 40 GHz, and allocations of WARC-79 and frequency management.

Katzenstein, W. E.↗
NASA NTRS1983

Space Platform Technology

Study examines possibility of using few large platforms in space instead of many small satellites to provide communications and other services. Study was based in large measure on user survey. List of 31 potential services was presented to leading telecommunications firms (including carriers, programers, users and manufacturers). Both favorable and antagonistic viewpoints were solicited.

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NASA NTRS1981

Office of Space Terrestrial Applications (OSTA)/Applications Data Service (ADS) data systems standards

Standards needed to interconnect applications data service pilots for data sharing were identified. Current pilot methodologies are assessed. Recommendations for future work are made. A preliminary set of requirements for guidelines and standards for catalogues, directories, and dictionaries was identified. The user was considered to be a scientist at a terminal. Existing and emerging national and international telecommunication standards were adopted where possible in view of new and unproven standards.

Walton, B. A.↗
NASA NTRS1981

ATS-6 engineering performance report. Volume 4: Television experiments

Experiments sponsored by the US Department of Health Education and Welfare are discussed, including telecommunications, Alaskan health service, Appalachian education satellite project, and the University of the West Indies. The Satellite Instructional Television Experiment in India is reviewed. Independent television experiments are addressed, including AIDSAT and Project Look Up.

Wales, R. O.↗
NASA NTRS1982

A summary of space flight missions supported by the Deep Space Network

Since the Ranger series in the 1960s the DSN evolved to a highly sophisticated telecommunications and data acquisition network. The 26 meter antennas were converted to 34 meters, and 64 meter antennas were built at all complexes. The L-band systems were changed to S-band, with X-band now also being used on Voyager and Pioneer 12. Ranging systems were developed and are used along with other techniques to determine exact spacecraft locations. Each mission is summarized and the launch date, objective, and results are presented.

Burke, E. S.↗
NASA NTRS1982

Space Operations Center system analysis study extension. Volume 4, book 1: SOC system analysis report

The Space Operations Center (SOC) orbital space station missions are analyzed. Telecommunications missions, space science, Earth sensing, and space testing missions, research and applications missions, defense missions, and satellite servicing missions are modeled and mission needs discussed. The satellite servicing missions are analyzed in detail, including construction and servicing equipment requirements, mission needs and benefits, differential drag characteristics of co-orbiting satellites, and satellite servicing transportation requirements.

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NASA NTRS1982

INTELSAT satellite scheduled for launch

The launch schedule for INTELSAT V-D, the fourth of a series of nine international telecommunications satellites, is presented. Satellite and launch vehicle specifications are presented.

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