Tracking and Data Relay Satellite Systems

Abstract

As a result of three years of study, it has been determined that implementation of a Tracking and Data Relay Satellite System (TDRSS), using satellites in synchronous orbit to relay data between low altitude earth orbital spacecraft (both manned and automated) and the various mission control centers could improve the capabilities of the NASA tracking and data acquisition networks. Such a system, by providing nearly continuous, real time access to low altitude spacecraft, would improve mission reliability; contribute immeasureably to the safety and morale of the crews of manned spacecraft; permit real time command and control of automated spacecraft, making their operation more versatile; enable experimenters to monitor their experiments in real time, perhaps thereby reducing the workload on data processing facilities; and, in general, relieve constraints upon mission planning and operations that are imposed by the short duration, intermittent contacts characteristic of ground based T&DA facilities. Furthermore, studies indicate that this improved T&DA system will probably present networks that it could pay operation. The benefits outlined above are an operational TDRSS consisting of ground stations. If initiation of commence in FY-1971, the launch of cost sufficiently less to operate than for itself within a few years of realizable upon the implementation of three satellites and their supporting the development of the system could the first two data relay satellites would be possible by CY-1974. Allowing for a thorough system checkout and evaluation, during which time the remaining satellites would be launched, a TDRSS could become operational by the end of CY-1975.