TDRS-1
Encyclopedia
TDRS-1, known before launch as TDRS-A, is an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 communications satellite
Communications satellite
A communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...

 which is operated by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 as part of the Tracking and Data Relay Satellite System
Tracking and Data Relay Satellite System
The Tracking and Data Relay Satellite System is a network of American communications satellites and ground stations used by NASA for space communications. The system was designed to replace an existing network of ground stations that had supported all of NASA's manned flight missions...

. It was constructed by TRW
TRW
TRW Inc. was an American corporation involved in a variety of businesses, mainly aerospace, automotive, and credit reporting. It was a pioneer in multiple fields including electronic components, integrated circuits, computers, software and systems engineering. TRW built many spacecraft,...

 and launched by on its maiden flight, STS-6
STS-6
STS-6 was a NASA Space Shuttle mission conducted using Space Shuttle Challenger, carrying the first Tracking and Data Relay Satellite, TDRS-1, into orbit. Launched on 4 April 1983, STS-6 was the sixth shuttle mission and the first of the ten missions flown by Challenger...

. While on the pad, problems were detected with the Shuttle's main engines and repairs were begun. During this time a severe storm caused contamination of the TDRS-1 while it was in the Payload Change-out Room on the Rotating Service Structure at the launch pad. Consequently, the satellite had to be taken back to its checkout facility, where it was cleaned and rechecked. Challenger finally lifted off from Launch Complex 39A
Kennedy Space Center Launch Complex 39
Launch Complex 39 is a rocket launch site at the John F. Kennedy Space Center on Merritt Island in Florida, USA. The site and its collection of facilities were originally built for the Apollo program, and later modified to support Space Shuttle operations. NASA began modifying LC-39 in 2007 to...

 of the Kennedy Space Center
Kennedy Space Center
The John F. Kennedy Space Center is the NASA installation that has been the launch site for every United States human space flight since 1968. Although such flights are currently on hiatus, KSC continues to manage and operate unmanned rocket launch facilities for America's civilian space program...

 at 18:30:00 GMT on 4 April 1983.

Following deployment from Challenger, TDRS-1 was to be raised to its operational geosynchronous orbit
Geosynchronous orbit
A geosynchronous orbit is an orbit around the Earth with an orbital period that matches the Earth's sidereal rotation period...

 by means of an Inertial Upper Stage
Inertial Upper Stage
The Inertial Upper Stage , originally known as the Interim Upper Stage, is a two-stage solid-fueled booster rocket developed by the U.S...

, which consisted of two solid rocket motors, the first used to raise the orbit's apogee
Apsis
An apsis , plural apsides , is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system...

, the second its perigee
Apsis
An apsis , plural apsides , is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system...

. The first burn was successful, however the IUS went out of control during the second burn. TDRS-1 separated from the upper stage in a lower than planned orbit. It was eventually raised to geosynchronous orbit by means of its attitude control system
Attitude control system
In spaceflight, the attitude control system or attitude determination and control system of a spacecraft consists of equipment to measure, report and change the orientation of the vehicle.- Components :...

. In order to achieve this, a team of engineers from the Goddard Space Flight Center
Goddard Space Flight Center
The Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...

 in Greenbelt, Maryland
Greenbelt, Maryland
Greenbelt is a city in Prince George's County, Maryland, United States. Contained within today's City of Greenbelt is the historic planned community now known locally as "Old Greenbelt" and designated as the Greenbelt Historic District...

 worked for nearly three months using six one-pound thrusters on the errant satellite to push it 8,600 miles higher in space. The failure was later identified as a collapsed second-stage nozzle Techroll Seal, a flexible ring which allows the nozzle to move and provide directional control. The Goddard engineers' successful effort required 39 adjustment burns to correct the elliptical orbit to the 22,300 mi high geosynchronous orbit desired for TDRS-1. In connection with this rescue, Goddard Space Center on November 26, 1984 honoured a group of 34 individuals with the Robert H. Goddard Award of Merit, the highest level of recognition the Goddard Space Center can bestow on its employees.

TDRS-1 had a design life of seven years, however in April 2008, it was still operational on the twenty-fifth anniversary of its launch. Over the years, the orbit inclination has been allowed to increase so that, for portions of the day, it was able to be used for communications with the North
North Pole
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is, subject to the caveats explained below, defined as the point in the northern hemisphere where the Earth's axis of rotation meets its surface...

 and South pole
South Pole
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earth's axis of rotation intersects its surface. It is the southernmost point on the surface of the Earth and lies on the opposite side of the Earth from the North Pole...

s. Along with Marisat F2, GOES 3
GOES 3
GOES 3, known as GOES-C before becoming operational, is an American geostationary weather and communications satellite. It was originally built for the National Oceanic and Atmospheric Administration as part of the Geostationary Operational Environmental Satellite system, and was launched in June...

 and LES-7, it was one of a number of satellites that were transferred to the US National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...

 for communications with the Amundsen-Scott South Pole Station
Amundsen-Scott South Pole Station
The Amundsen–Scott South Pole Station is the American scientific research station on the high plateau of Antarctica. This station is located at the southernmost place on the Earth, the Geographic South Pole, at an elevation of 2,835 meters above sea level.The original Amundsen-Scott Station was...

. After Marisat was retired, TDRS-1 became the primary means of communication with the research station. The last functioning traveling-wave tube amplifier aboard TDRS-1 failed in October 2009, rendering the spacecraft unusable for communications purposes.

The craft was moved into a decommissioning orbit beginning on or about October 21, 2009. Decommissioning was started on June 5, 2010 and pacification was completed on June 27, 2010. NASA has repositioned TDRS-3
TDRS-3
TDRS-3 , known before launch as TDRS-C, is an American communications satellite which is operated by NASA as part of the Tracking and Data Relay Satellite System...

to assume the duties of TDRS-1.
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