Space Communications

Pursuant to a congressional request, GAO reviewed the efficiency and effectiveness of the National Aeronautics and Space Administration's (NASA) system for scheduling usage of the Tracking and Data Relay Satellite System (TDRSS).

GAO found that: (1) since scheduling TDRSS usage is a complicated process, spacecraft project users generate a tentative schedule of the precise contact times and types of TDRSS services needed 3 weeks before service is required; (2) conflicts between users for the same service at the same time are resolved by changing the requested start time, changing the type of service requested, or switching the service requested to a different TDRSS satellite or antenna; (3) the Hubble Space Telescope and the space shuttle are the two biggest sources of schedule disruption; (4) inadequate automated tools have made the conflict resolution process more tedious, labor-intensive, and potentially error-prone than necessary; (5) TDRSS users are concerned that the scheduling system may be inadequate to handle the expected increase in demand for communications services; (6) although TDRSS has been generally very reliable in providing service when needed, TDRSS failure to support user missions could have serious economic and scientific ramifications; (7) developing an efficient scheduling system to accommodate future growth would require an entirely new system design which has been planned but will not be available until fiscal year 1997 at the earliest; and (8) NASA is reluctant to implement enhancements that may streamline the conflict resolution process, because its data were not comprehensive enough to accurately predict the impact of additional TDRSS users on the scheduling process.

Recommendations

Our recommendations from this work are listed below with a Contact for more information. Status will change from "In process" to "Open," "Closed - implemented," or "Closed - not implemented" based on our follow up work.

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