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The application of remote sensing technology in the fields of health and education is examined. The technology and accomplishments of ATS 6 and the development of a nationwide telecommunications system to meet the varied needs of the health and education communities are among the topics discussed. The economic and social aspects of utilizing and benefiting from remote sensing technology are stressed.
Possible improvements in the Deep Space Network and their potential effect on the telecommunications limit of Pioneer 10 and on Pioneer 11 Saturn encounter are discussed.
Computer program listings as well as graphical and tabulated data needed by the analyst to perform a BRAVO analysis were examined. Graphical aid which can be used to determine the earth coverage of satellites in synchronous equatorial orbits was described. A listing for satellite synthesis computer program as well as a sample printout for the DSCS-11 satellite program and a listing of the symbols used in the program were included. The APL language listing for the payload program cost estimating computer program was given. This language is compatible with many of the time sharing remote terminals computers used in the United States. Data on the intelsat communications network was studied. Costs for telecommunications systems leasing, line of sight microwave relay communications systems, submarine telephone cables, and terrestrial power generation systems were also described.
The joint German and NASA project Helios is reviewed with special attention paid to the advanced technology required to accomplish the mission, i.e., thermal (second surface mirrors), telecommunications (despun high gain antenna) and power (high temperature solar cells). Engineering and system results are presented for the Mar. 15, 1975 perihelion passage of Helios A to within 0.31 AU of the sun. Also discussed are mission design, the experiment performance, spacecraft configurations, the launch vehicle, and tracking and data acquisition. Tables are included describing the history of German-U.S. cooperation, prelaunch milestones and significant mission events, experiments performance during primary mission and mission dependent requirements, development problems and solutions.
Recent exploration of the planets has been highlighted by the development of visual imaging systems carried on board the spacecraft. This paper describes the evolution of planetary camera systems from the earliest reconnaissance flight to Mars in 1965 (Mariner 4) through the planned mission to Jupiter and Saturn in 1977. Advances in telecommunication performance, mission planning and operations, and digital processing of images are also discussed. Science objectives and changes in the imaging systems required to meet these objectives are discussed for the Mariner Mars 1971 (Mariner 9), Mariner Venus-Mercury (Mariner 10), Viking 1975 (Mars Orbiter), and Mariner Jupiter-Saturn 1977 missions. The last section of the paper describes future plans for imaging experiments based on cameras using solid-state sensors, particularly charge-coupled devices.
Some physical characteristics of radio transmission links and the technology of PCM modulation combine with the Radio Regulations of the International Telecommunications Union to define a communications channel having a determinable channel capacity, error rate, and sensitivity to interference. These characteristics and the corresponding limitations on EIRP, power flux density, and power spectral density for space service applications are described. The ITU regulations create a critical height of 1027 km where some parameters of the limitation rules change. The nature of restraints on power spectral density are discussed and an approach to a standardized representation of Necessary Bandwidth for the Space Services is described. It is shown that, given the PFD (power flux density) and PSD (power spectral density) limitations of radio regulations, the channel performance is determined by the ratio of effective receiving antenna aperture to system noise temperature. Based on this approach, the method for a quantitative trade-off between spectrum spreading and system performance is presented. Finally, the effects of radio frequency interference between standard systems is analyzed.
The Communications Technology Satellite (CTS) is a high-power broadcast satellite launched by NASA on January 17, 1976. CTS is the first satellite to operate at a frequency of 12 gigahertz and incorporates technology making possible new satellite telecommunications services. CTS is a cooperative program of the United States and Canada. This paper presents the results of the United States experimental activity to date. Wide segments of the population are involved in the Experiments Program, including the scientific community, other government agencies, industry, and the education and health entities. The experiments are associated with both technological objectives and the demonstration of new community and social services via satellite.
An assessment was made of telecommunications capability between the radio frequency subsystem on the Mariner Jupiter-Spacecraft and the Deep Space Network.
An emergency medical system is characterized. Applications of NASA technology in biomedical telecommunication and bioinstrumentation are explored. The training and effectiveness of paramedics, technicians, nurses, and physicians are evaluated as applied to emergency situations and the operations of trauma centers. Civilian and military aeromedical evacuation is discussed.
The application of telecommunications and telecomputing was investigated as a means of reducing NASA's consumption of natural resources and the proliferation of paper copies of correspondence. The feasibility, operational advantages, and limitations of decentralized (remote) neighborhood offices (NOC) linked through an electronic network are demonstrated. These offices are joined to a management information system for correspondence tracking, and to an administrative office center service based on the use of magnetic medium word processing typewriters which handle the daily typing load. In connection with an augmented teleconference network, a uniform means is provided for creating, storing, and retrieving administrative documents, records, and data, while simultaneously permitting users of the system to track their status. Information will be transferred without using paper - merely through digital electronic communication and display, as a step toward the establishment of an agency-wide electronic mail system.
NASA-Ames Research Center and Stanford University in California, and Carleton University in Ottawa, Canada, are designing a curriculum-sharing experiment which will use compressed digital television. The experiment will permit evaluation of the potential of curriculum sharing by two universities which are geographically distant, but capable of transmitting and receiving television signals. The evaluation of the curriculum sharing per se will include inputs from faculty, staff and students at both institutions. Accessibility to and acceptability of each other's curriculum will be studied and recorded. Adjustments to differences in academic terms, class meeting times, teaching styles and similar issues will be closely monitored. It is hoped that this experiment will provide long-range planners the kind of information which they will need when designing large-scale educational telecommunications systems for the future.
Public service programs using NASA's ATS-6 and CTS satellites are discussed. Examples include the ATS-6 Health and Education Telecommunications experimental program and the use of CTS to enable students in one university to take courses presented at another distant university. Possible applications of satellite communication systems to several areas of public service are described, and economic and political obstacles hindering the implementation of these programs are considered. It is suggested that a federally sponsored program demonstrating the utility of satellites accomodating a large number of small terminals is needed to encourage commercial satellite operations.
Digital correlator requires only few integrated circuits to determine synchronization of two 24-bit digital words. Circuit is easily reduced or expanded to accommodate shorter or longer words and can be utilized in industrial and commercial data processing and telecommunications.
The Public Service Satellite Consortium evaluated prospects for satellite telecommunications in four areas of the public service: the U.S. health care system, elementary and secondary education, American libraries, and that sector of the public service which is concerned with the provision of continuing education to health professionals. Three important conclusions were reached. First, throughout the public service there are three recurring needs: improved access, cost containment, and maintenance of quality. Appropriate application of communication satellite systems could ameliorate each of these concerns. Second, there appears to be an enormous latent demand for data communication services throughout the public service. The potential demand in 1982 to support requirements in hospital administration, library services and other information-retrieval activities, equipment maintenance, and environmental monitoring may be in excess of $300 million a year. Third, administrative applications of data communication networks show particular promise, especially in rural areas.
'Ariadne', the European rocket, was found to be less costly than the American space shuttle, judging by the price proposals sent to Intelsat for the orbiting of its three latest telecommunications satellites in the Intelsat 5 series. The 'Ariadne' is being offered by the ESA and CNES at a ceiling price of $20 million, while the shuttle is priced by NASA at $22.5 million under the same condition. Neither the U. S. nor ESA have endorsed these prices officially. They are being presented as estimates. The 'Ariadne' has a ceiling price, which can only be adjusted downwards, if need be. The launching prices of both of these spacecraft do not include the cost of adapting the Intelsat 5 satellites, designed for the Atlas Centaur rocket.
A set of measured data on the X-band performance of the three 64-meter deep space stations was obtained for use in future mission telecommunication design and predictions. The test configuration and measurement procedure is described. A method of modelling attenuation due to the atmosphere is given. Radio source brightness temperature and flux density are reviewed.
Disdrometer measurements and radar reflectivity measurements were injected into a computer program to estimate the path attenuation of the signal. Predicted attenuations when compared with the directly measured ones showed generally good correlation on a case by case basis and very good agreement statistically. The utility of using radar in conjunction with disdrometer measurements for predicting fade events and long term fade distributions associated with earth-satellite telecommunications is demonstrated.
This paper presents forecasts of likely changes in broadcast satellite technology, the technology of ground terminals, and the technology of terrestrial communications competitive with satellites. The impacts of these changes in technology are then assessed, using a cross-impact model of U.S. domestic telecommunications, to determine the consequences of various possible changes in communications satellite technology. These consequences are discussed in terms of various possible services, for households, businesses, and specialized customers, which might become economically viable as a result of improvements in satellite technology.