PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. PHONE (818) 354-5011

       The Deep Space Network, operated for NASA by the Jet Propulsion Laboratory, will provide tracking support for the STS-26 flight of the space shuttle Discovery and for the deployment and on-orbit checkout of Discovery's payload, the Tracking and Data Relay Satellite-C (TDRS-C).

       Shuttle support will be provided by the 26-meter antennas at Goldstone, Calif.; near Canberra, Australia; and near Madrid, Spain. The Goldstone 26-meter antenna will provide prime support for the shuttle launch and landing phases of the mission.

       The DSN 26-meter antennas will track Discovery during the launch sequence. Current flight plans call for Discovery's crew to open the shuttle's payload bay doors on the second orbit, and then transmit the information on TDRS-C's tape recorder to Earth.

       The 26-meter DSN antenna at Goldstone will receive the data, and then concentrate on the TDRS-C spacecraft's radio-frequency checks, beginning with orbit 3. If TDRS-C is in good condition, it will be deployed from the shuttle's cargo bay on orbit 5.

       Ignition of the IUS solid-rocket motor will take place on orbit 6. Other NASA antennas will then track the shuttle and the DSN will track TDRS-C and its inertial upper stage as they reach geosynchronous orbit.

       (Geosynchronous orbit is at 22,300 miles altitude, where the spacecraft makes one orbit of Earth in 24 hours. TDRS-C will then appear to be stationary over the same spot on Earth. The exact location of TDRS-C will be determined after its on-orbit checkout is complete.)

       The DSN will continue to track TDRS-C until four days into the shuttle flight, when it will return to tracking Discovery for the remainder of the flight and the landing at Edwards Air Force Base, Calif.

       After Discovery has landed, the DSN antennas will once again track TDRS-C.

       TDRS-C is an advanced communications satellite. The first TDRS was launched from the space shuttle in April 1983. The second was lost in the explosion of the Challenger in January 1986.

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9/13/88 DB
#1210