Here are a few online references with interesting information about the shuttles:
Enterprise (OV-101) - The first
shuttle, it was named for a rather famous fictional spaceship and was a test vehicle used for suborbital flight and landing tests and was never sent into space.
Columbia (OV-102) - The oldest
orbiter in the current fleet which is currently undergoing upgrades to its online systems.
Challenger (STA-099/OV-99) -
Originally built as a test vehicle and designated STA-099, the decision was made in January, 1979 to have it converted into a fully-capable orbiter. On January
28, 1986, Challenger and the seven astronauts on board, including Sharon Christa McAuliffe who was to become the first civillian in space, met with a tragic fate 73 seconds after launch.
Discovery (OV-103) - This Orbiter
first flew on August 30, 1984. It is the
vehicle that will be launched tonight.
Atlantis (OV-104) - Completed on
March 6th, 1985, this vehicle was the first to undergo conversion to the new glass cockpit system.
Endeavor (OV-105) - While Discovery and Atlantis were under construction, NASA decided it would be a good idea to maintain a set of 'structural spares' in case an orbiter was damaged. When the Challenger was destroyed, these structural spares were assembled to create Endeavor as a replacement. Endeavor first flew STS-49 on May 5, 1992.
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