Artist's impression of a TDRS satellite in orbit
|Launch date||28 January 1986
|Carrier rocket||Space Shuttle Challenger
STS-51-L / IUS
|Launch site||KSC LC-39B|
|Mission duration||7 years (planned)
73 seconds (achieved)
|Regime||Failed to orbit
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.
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.
STS-51-L launched with TDRS-B at 16:38 GMT on 28 January 1986. The Shuttle disintegrated 73 seconds after launch due to an o-ring failure in one of the Solid Rocket Boosters, killing the seven astronauts aboard.
Once it reached orbit, TDRS-B was to have been given the operational designation TDRS-2. Although normal practice was to reassign operational designations in the event of launch failures, the TDRS-2 designation was not reassigned, and when TDRS-C was launched, it became TDRS-3. Debris from TDRS-B was recovered along with the wreckage of Challenger
- Wade, Mark. "STS-12". Encyclopedia Astronautica. Retrieved 2009-06-24.
- Krebs, Gunter. "TDRS 1, 2, 3, 4, 5, 6". Gunter's Space Page. Retrieved 2009-06-25.
- McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 2009-06-24.
- "Tracking and Data Relay Satellite System (TDRSS)". NASA Space Communications. Retrieved 2009-06-25.