TDRS-6

TDRS-6, known before launch as TDRS-F, 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, and is based on a custom satellite bus which was used for all seven first generation TDRS satellites.

History

TDRS-F was deployed from Space Shuttle Endeavour during the STS-54 mission in 1993. Endeavour was launched from Launch Complex 39B at the Kennedy Space Center, at 13:59:30 GMT on 13 January 1993. TDRS-F was deployed from Endeavour around six hours after launch, and was raised to geosynchronous orbit by means of an Inertial Upper Stage.

Deployment

The two-stage solid-propellent Inertial Upper Stage made two burns. The first stage burn occurred shortly after deployment from Endeavour, and placed the satellite into a geosynchronous transfer orbit. At 02:26 GMT on 14 January it reached apogee, and the second stage fired, placing TDRS-F into geosynchronous orbit. At this point it received its operational designation, TDRS-6.

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 Space Shuttle Challenger disintegrated 73 seconds after launch.

History

TDRS-B was launched in the payload bay of Challenger, attached to an Inertial Upper Stage (IUS). It was to have been deployed from the Shuttle in low Earth orbit. The IUS would have then performed two burns to raise the satellite into a geosynchronous orbit. On the previous TDRS launch, TDRS-1, the IUS second-stage motor malfunctioned following the first-stage burn, resulting in a loss of control, and delivery of the satellite into an incorrect orbit.

Launch failed

TDRS-B was originally scheduled for launch on STS-12 in March 1984, however it was delayed and the flight cancelled following the IUS failure on TDRS-1. It was later re-manifested on STS-51-E, however this too was cancelled due to concerns over the reliability of the IUS. It was eventually assigned to STS-51-L, which was to also carry the SPARTAN-Halley astronomy satellite.

TDRS-8

TDRS-8, known before launch as TDRS-H, is an American communications satellite which is operated by NASA as part of the Tracking and Data Relay Satellite System. It was constructed by Boeing is based on the BSS-601 satellite bus.

Launch

Its launch was contracted by International Launch Services, using an Atlas IIA carrier rocket. The launch occurred on 30 June 2000, at 12:55 GMT from Space Launch Complex 36A at the Cape Canaveral Air Force Station.

It was the first Advanced Tracking and Data Relay Satellite to be launched. Due to a malfunction of the multiple-access phased array antenna the spacecraft did not provide the expected level of performance for eighteen of the communications services that it was to provide. The same problem was found and corrected on the TDRS-9 and TDRS-10 satellites prior to their launches.

Orbit

Following its launch it raised itself into geostationary orbit by means of its onboard R-4D apogee motor, and was positioned at 150° West for on-orbit testing. After testing was complete, it was moved to 171° West from where it provides communications services to spacecraft in Earth orbit, including the Space Shuttle and International Space Station.