yee@ames.arc.nasa.gov (Peter E. Yee) (11/17/88)
Jeff Vincent
Headquarters, Washington, D.C. November 14, 1988
James Elliott
Goddard Space Flight Center, Greenbelt, Md.
RELEASE: 88-157
SHUTTLE-LAUNCHED SATELLITE PASSES EARLY TESTS WITH FLYING COLORS
The Tracking and Data Relay Satellite (TDRS), launched by
the Space Shuttle Discovery on Sept. 29, has performed flawlessly
on all tests to date and may support the next Space Shuttle
mission, NASA officials at Goddard Space Flight Center,
Greenbelt, Md., announced today.
Since its launch by the crew of Discovery, the 5,000-pound
communications satellite, known as TDRS-3, has been moved for
testing to 150 degrees west longitude over the Equator. This
location is best for communications with the White Sands Ground
Terminal in New Mexico, for spacecraft antenna testing, for pre-
mission tests and mission support for STS-27.
Following deployment of the satellite's antennas and solar
arrays, the satellite's thrusters were first fired on Oct. 2 to
start TDRS drifting towards the test location. The satellite's
movement was stopped by additional firings on Oct. 11 and 12 when
it arrived on station.
Spacecraft communication systems were activated between Oct.
7 and 18. All systems performed flawlessly and testing is ahead
of schedule, according to Dr. Dale W. Harris, TDRS project
manager at Goddard. Although tests and calibrations will not be
complete, NASA hopes to use the TDRS-3, along with TDRS-1
launched in April 1983, for improved communications during the
STS-27 mission.
TDRS-3 is the third to be launched. The first has been in
operation since 1983 and is located at 41 degrees west
longitude. The second was lost with the Challenger. The fourth,
to complete NASA's constellation of three on-orbit satellites, is
scheduled for launch on the Discovery in February 1989.
TDRS provides comprehensive telecommunications services by
relaying voice, television, digital and analog signals between
low-Earth-orbiting spacecraft, including the Space Shuttle and
the ground.
The TDRS satellites are built by TRW Space & Technology
Group, Redondo Beach, Calif. The satellites are owned and
operated by Contel Federal Systems of Fairfax, Va., which also
operates the White Sands Ground Terminal under a lease agreement
with NASA.
Orbiting at 22,250 miles above the Earth, the tracking and
data relay satellites look down on NASA's fleet of low-Earth-
orbiting spacecraft and shuttles, tracking them worldwide and
relaying two-way communications between them and mission control
centers through a single ground station at White Sands, N.M.
NASA established the Tracking and Data Relay Satellite
System (TDRSS) to increase the flow of information between low-
Earth-orbiting spacecraft and the ground. TDRSS will provide
significantly greater geographical coverage than that provided by
NASA's worldwide network of ground-based tracking stations.
With two operational TDRS, low-orbit spacecraft are in
communication with Earth for about 85 percent of each orbit.
Before the TDRS system, spacecraft could communicate with Earth
only when they were in sight above one of several ground tracking
stations, typically less than one-sixth of an orbit.johnson@ncrcce.StPaul.NCR.COM (Wayne D. T. Johnson) (11/17/88)
In article <18257@ames.arc.nasa.gov> yee@ames.arc.nasa.gov (Peter E. Yee) writes: > TDRS-3 is the third to be launched. The first has been in >operation since 1983 and is located at 41 degrees west >longitude. The second was lost with the Challenger. The fourth, >to complete NASA's constellation of three on-orbit satellites, is >scheduled for launch on the Discovery in February 1989. > I think I remember that the French were to launch one of the TDRS series and ended up by orbiting it and several spares on the bottom of the Atlantic. Could I be mistaking this with another communication satalite? Even though there are lots who might think otherwise, GOOD JOB NASA and to all those employees and contractors who made it happen! -- Wayne Johnson (Voice) 612-638-7665 NCR Comten, Inc. (E-MAIL) W.Johnson@StPaul.NCR.COM or Roseville MN 55113 johnson@c10sd1.StPaul.NCR.COM These opinions (or spelling) do not necessarily reflect those of NCR Comten.
mcdowell@cfa250.harvard.edu (Jonathan McDowell) (11/18/88)
From article <893@ncrcce.StPaul.NCR.COM>, by johnson@ncrcce.StPaul.NCR.COM (Wayne D. T. Johnson): > I think I remember that the French were to launch one of the TDRS series and > ended up by orbiting it and several spares on the bottom of the Atlantic. > Could I be mistaking this with another communication satalite? Yes, you are mistaken; the TDRS series are designed for Shuttle launch only, although Titan 3 may be used as a backup in a few years. Perhaps you are thinking of GTE's Spacenet 3, which did do some underwater exploration on an Ariane. Arianespace has not launched any comsats nearly as big as TDRS. Jonathan McDowell