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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 739 records · Page 41

Communications system research

Coding, synchronization, combinatorial, multiple access, propagation, and permutation studies for telecommunications systems

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JPL Quarterly Technical Review, Volume 1, Number 3

Summary report including studies on computer programs, management systems, materials, orbits and trajectories, photography, power sources, propulsion, and telecommunication for space missions

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Development and testing of the infrared interferometer spectrometer for the Mariner Mars 1971 spacecraft

The design, development and testing of the infrared interferometer spectrometer is reported with emphasis on the unique features of the Mariner instrument as compared to previous IRIS instruments flown on the Nimbus meteorological research satellites. The interferometer functions in the spectral range from 50 microns to 6.3 microns. A noise equivalent radiance of 0.5 X 10 to the -7th power W/sq cm/ster/cm has been achieved. Major improvements that were implemented included the cesium iodide beamsplitter and electronic features to suppress the effect of vibration on the Michelson mirror motion and digital filtering through the summation of increased sampling of the infrared signal. A bit error detection and correction scheme was also implemented in order to recover the science data with a higher level of confidence over the telecommunication link.

Hanel, R. H.↗

Information transfer satellite concept study. Volume 4: computer manual

The Satellite Telecommunications Analysis and Modeling Program (STAMP) provides the user with a flexible and comprehensive tool for the analysis of ITS system requirements. While obtaining minimum cost design points, the program enables the user to perform studies over a wide range of user requirements and parametric demands. The program utilizes a total system approach wherein the ground uplink and downlink, the spacecraft, and the launch vehicle are simultaneously synthesized. A steepest descent algorithm is employed to determine the minimum total system cost design subject to the fixed user requirements and imposed constraints. In the process of converging to the solution, the pertinent subsystem tradeoffs are resolved. This report documents STAMP through a technical analysis and a description of the principal techniques employed in the program.

Bergin, P.↗

Delta modulation

A paper describing the basic delta modulation systems studied was published. A second paper, describing the systems response to voice and video was presented at the International Communications Conference in June 1972, and a third paper describing several delta modulation systems used for voice and video is scheduled for presentation at the National Telecommunications Conference in December 1972.

Shilling, D. L.↗

Outer planet entry probe system study. Volume 2: Supporting technical studies

The environment, science investigations, and general mission analysis considerations are given first. These data are followed by discussions of the studies pertaining to the planets Jupiter, Saturn, Uranus, and Neptune. Except for Neptune, each planet discussion is divided into two parts: (1) parametric activities and (2) probe definition for that planet, or the application of a given probe for that planet. The Neptune discussion is limited to parametrics in the area of science and mission analysis. Each of the probe system definitions consists of system and subsystem details including telecommunications, data handling, power pyrotechnics, attitude control, structures, propulsion, thermal control, and probe to spacecraft integration. The first configuration is discussed in detail and the subsequent configuration discussions are limited to the differences. Finally, the hardware availability to support a probe system and commonality of science, missions, and subsystems for use at the various planets are considered.

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Trends in NASA communication satellites

Satellite telecommunications can help to satisfy several national needs such as education, health care, cultural opportunities, and data transfer. There are current experiments being conducted with NASA spacecraft ATS 1, 3, and 5 in an attempt to satisfy these national needs. Future experiments are planned for the ATS F/G and CTS spacecrafts. The next generation of communications satellites must provide multiple region coverage, multichannel capability, high quality TV pictures, and must allow low cost ground receivers to be used. The proposed NASA spacecrafts, ATS H/I, will satisfy these requirements. Other countries of the world can benefit from ATS H/I technology.

Sivo, J. N.↗

Space station communications using interplex modulation.

Description of a multichannel PCM-PSK-PM modulation scheme called interplex which reduces cross-modulation loss and excess carrier reference power of conventional systems when the number of channels is small. In systems with equal channels, interplex is more efficient when the number of channels is not greater than four. The number of channels which can be combined efficiently with interplex increases if there are many low-power channels and only one high-power link. The scheme can be implemented in existing systems without significant hardware changes and appears to be suitable for use in a multichannel space-station telecommunications system.

Butman, S.↗

Satellites for U.S. education - Needs, opportunities and systems.

This paper presents results of a continuing interdisciplinary study of the potential applications of Fixed- and Broadcast-Satellites for educational information transfer in the United States for the period 1975-1985. The status of U.S. education is examined and needs, trends and issues are discussed. The existing educational telecommunications infrastructure is examined and opportunities for satellite services are defined. Potential uses include networking of educational institutions and service centers for delivery of public and instructional television, computer-aided instruction, computing and information resources to regions and groups not now adequately served. Systems alternatives and some of the organizational and economic issues inherent in the deployment of an educational satellite system are discussed.-

Morgan, R. P.↗

A NASA program to characterize propagation and interference for space applications.

The NASA interference and propagation program was planned by a multiagency committee at the request of the Director of Telecommunications Policy. Initially, emphasis was placed on preparation of the United States position on interference between satellite Earth stations and microwave relay links at frequencies below 10 GHz for the 1971 World Administrative Radio Conference (WARC-71). The program objective is to acquire, analyze, and disseminate space propagation data for a user community of space systems designers, operators and regulatory agencies. Measurements and analyses are being performed which lead to a centralized data base for characterization of radio frequency phenomena required to design space communications systems.

Eckerman, J.↗