Space Shuttle Enterprise test flight. Historical image of the Space Shuttle prototype Enterprise flying freely after being released from NASA's 747 Shuttle Carrier Aircraft (SCA), during its second free flight of the shuttle program's Approach and Landing Tests (ALT). Enterprise was the first shuttle orbiter built by NASA. During a 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 over Rogers Dry Lakebed, Dryden Flight Research Center, California, USA, on 1st January 1977.