PIONEER NASA SPACECRAFT CELEBRATES 20 YEARS OF SERVICE

NASA's original Tracking and Data Relay Satellite (TDRS-1), launched from the Space Shuttle Challenger (STS-6) in April 1983, went from almost being "lost in space," to a remarkable example of the agency's 'can do, never quit' attitude. On April 4, TDRS-1 celebrates 20 years of outstanding service and 'firsts.'

After deployment, the spacecraft's upper stage failed. NASA engineers at the Goddard Space Flight Center (GSFC) came to TDRS-1's rescue using the spacecraft's tiny, one-pound thrusters. They used the thrusters, over several months, to nudge the satellite into a geosynchronous Earth orbit. Because TDRS-1 has been inclining in its orbit almost one degree per year since its deployment, this satellite has been used in ways never expected.

TDRS-1 began life by opening a new era in NASA satellite communications. It tracked low Earth-orbiting satellites, enabling NASA to issues commands and receive telemetry through most of their orbit. Working solo, TDRS-1 provided more communication coverage, in support of the September 1983 Shuttle mission, than the entire network of NASA tracking stations had provided in all previous Shuttle missions.

The second TDRS satellite was destroyed in the Challenger accident in January 1986, so TDRS-1 was left alone in orbit for several years to carry the load. In March 1992, NASA called on TDRS-1 to quickly aid the agency's Compton Gamma Ray Observatory (CGRO), when data recorders onboard the spacecraft failed.

Engineers constructed a ground station in Canberra, Australia to close the zone of communications exclusion and minimize science data loss. Controllers re-positioned TDRS-1 in view of the new station. TDRS-1 was able to supplement the communications services provided by the other on-orbit TDRS satellites, providing the CGRO with downlink capability over previously inaccessible portions of its orbit. Since 1992, NASA has used TDRS-1 for communications to very high latitude ground sites.

Other TDRS-1 firsts include:

* First satellite used to support Kennedy Space Center launches in the early 1990s, returning real time telemetry;

* Closed the zone of communications exclusion over the Indian Ocean, providing 100 percent coverage of the Space Shuttle and low inclination orbiting satellites via the TDRS constellation;

* First connection to the Internet, and the first live Web cast from the North Pole, using TDRS-1 (recorded in Ripley's Believe It Or Not);

* First Pole-to-Pole phone call using TDRS-1 to connect to the South Pole and Iridium for the North Pole (recorded in Ripley's Believe It Or Not and Guinness World Records in April 1999);

Due to increasing orbit inclination, TDRS-1 was the first satellite able to see both Poles. In cooperation with the National Science Foundation (NSF), an uplink/downlink station for TDRS-1 was installed in January 1998 at the exact South Pole. This terminal has given scientists at the Amundsen-Scott Base year around ability to return high volumes of science data to the continental U.S. daily for about five hours.

NASA considered retiring the aging satellite in 1998, but instead allowed the NSF and others to use it for scientific, humanitarian and educational purposes. TDRS-1 was used in 1998 for a medical emergency at McMurdo Station. Its high-speed connectivity allowed scientists to conduct a telemedicine conference, allowing doctors in the U.S. to guide a welder through a real operation on a woman diagnosed with breast cancer.

In 2000, TDRS-1 successfully supported an extended NSF/Coast Guard science expedition to the Gakal Ridge just below the North Pole. "We in the Space Network are extremely happy with the performance of TDRS-1 and look forward to many more 'firsts,'" said Dick Schonbachler, Mission Commitment Manager at GSFC. Since TDRS-1 entered service in 1983, NASA has placed nine TDRS into specific geosynchronous orbits. The first six were built by TRW. Boeing Satellite Systems built three enhanced satellites. The Space Network uses the TDRS System to relay data and communications from more than one dozen customers, including the Shuttle, International Space Station and the Hubble Space Telescope.

For more information about TDRS-1 and the TDRS System, on the Internet, visit:

http://nmsp.gsfc.nasa.gov/tdrss/tdrsshome.html