TDRS-1, 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