The Space Shuttle Now

: The "workhorse" of the fleet, it flew 39 missions, including the launch of the Hubble Space Telescope.

: The first shuttle to fly into space in 1981; tragically lost during re-entry in 2003. The Space Shuttle

: A prototype used for atmospheric flight tests; it never flew in space but is currently on display at the Intrepid Sea, Air & Space Museum. How It Worked : The "workhorse" of the fleet, it flew

Five flight-worthy orbiters were constructed for the program: : The "workhorse" of the fleet

The Shuttle system consisted of three primary components that worked together for launch:

: Flew the final mission of the program (STS-135) in July 2011.

40 Years Ago: Space Shuttle Enterprise rolls to the Pad - NASA