Space Shuttle Enterprise piggyback flight. Historical image of the Space Shuttle prototype Enterprise mounted to the back of the NASA 905 Shuttle Carrier Aircraft (SCA), during the first of the shuttle program's Approach and Landing Tests (ALT). Enterprise was the first shuttle orbiter built by NASA. During this nearly one-year-long series of tests, Enterprise was taken up on the SCA to study the aerodynamics of the mated vehicles and, in a series of five free flights, the glide and landing characteristics of the orbiter prototype. Photographed at the Dryden Flight Research Center, California, USA, in February 1977.