TDRS-7
Encyclopedia
TDRS-7, known before launch as TDRS-G, is an American
communications satellite
which is operated by NASA
as part of the Tracking and Data Relay Satellite System
. It was constructed by TRW
as a replacement for TDRS-B
, which had been lost in the Challenger accident
, and was the last first-generation TDRS satellite to be launched. It is based on a custom satellite bus
which was used for all seven first generation TDRS satellites. Whilst similar to its predecessors, it differed from them slightly in that twelve G/H band (IEEE C band) transponders which had been included on the previous satellites were omitted. It was the last communications satellite, other than amateur radio
spacecraft, to be deployed by a Space Shuttle.
The TDRS-G satellite was deployed from during the STS-70
mission in 1995. Discovery was launched from Kennedy Space Center
Launch Complex 39B
at 13:41:55 GMT on 13 July 1995. TDRS-G was deployed from Discovery around six hours after launch, and was raised to geosynchronous orbit
by means of an Inertial Upper Stage
.
The twin-stage solid-propellent Inertial Upper Stage made two burns. The first stage burn occurred around an hour after deployment from Discovery, and placed the satellite into a geosynchronous transfer orbit. At 02:30 on 14 July it reached apogee, and the second stage fired, placing TDRS-G into geostationary orbit. At this point it received its operational designation, TDRS-7. It was placed at a longitude 150 degrees West of the Greenwich Meridian, where it underwent on-orbit testing. In May 1996 it was moved to 171° West where it was stored as an in-orbit spare, and subsequently entered service. In December 2003, it was relocated to 150.5° West. It arrived the next month, and was returned to storage as a reserve satellite.
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,...
as a replacement for TDRS-B
TDRS-B
TDRS-B was an American communications satellite, which was to have formed part of the Tracking and Data Relay Satellite System. It was destroyed when the disintegrated 73 seconds after launch....
, which had been lost in the Challenger accident
Space Shuttle Challenger disaster
The Space Shuttle Challenger disaster occurred on January 28, 1986, when Space Shuttle Challenger broke apart 73 seconds into its flight, leading to the deaths of its seven crew members. The spacecraft disintegrated over the Atlantic Ocean, off the coast of central Florida at 11:38 am EST...
, and was the last first-generation TDRS satellite to be launched. It is based on a custom satellite bus
Satellite bus
A satellite bus or spacecraft bus is the general model on which multiple-production satellite spacecraft are often based. The bus is the infrastructure of a spacecraft, usually providing locations for the payload .They are most commonly used for geosynchronous satellites, particularly...
which was used for all seven first generation TDRS satellites. Whilst similar to its predecessors, it differed from them slightly in that twelve G/H band (IEEE C band) transponders which had been included on the previous satellites were omitted. It was the last communications satellite, other than amateur radio
Amateur radio
Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...
spacecraft, to be deployed by a Space Shuttle.
The TDRS-G satellite was deployed from during the STS-70
STS-70
STS-70 was the 21st flight of the Space Shuttle Discovery, and the last of 7 shuttle missions to carry a Tracking and Data Relay Satellite . This was the first shuttle mission controlled from the new Mission Control Center room at the Johnson Space Center in Houston...
mission in 1995. Discovery was launched from 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...
Launch Complex 39B
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...
at 13:41:55 GMT on 13 July 1995. TDRS-G was deployed from Discovery around six hours after launch, and was raised to 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...
.
The twin-stage solid-propellent Inertial Upper Stage made two burns. The first stage burn occurred around an hour after deployment from Discovery, and placed the satellite into a geosynchronous transfer orbit. At 02:30 on 14 July it reached apogee, and the second stage fired, placing TDRS-G into geostationary orbit. At this point it received its operational designation, TDRS-7. It was placed at a longitude 150 degrees West of the Greenwich Meridian, where it underwent on-orbit testing. In May 1996 it was moved to 171° West where it was stored as an in-orbit spare, and subsequently entered service. In December 2003, it was relocated to 150.5° West. It arrived the next month, and was returned to storage as a reserve satellite.