The “Space Shuttle Enterprise” (NASA Orbiter Vehicle Designation: “OV-101”) was the first Space Shuttle orbiter, or the orbital spacecraft of the Space Shuttle program operated by NASA (“National Aeronautics and Space Administration”), the space agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.
It was built for NASA as part of the Space Shuttle program, officially called “Space Transportation System” (“STS”), the United States government’s manned launch vehicle program from 1981 to 2011, to perform test flights in the atmosphere. It was constructed without engines, the “RS-25,” otherwise known as the “Space Shuttle Main Engine” (“SSME”), a liquid-fuel cryogenic rocket engine that was used on NASA’s Space Shuttle and is planned to be used on its successor, the Space Launch System, or a functional heat shield, designed to shield a substance from absorbing excessive heat from an outside source by either dissipating, reflecting or simply absorbing the heat, and was therefore not capable of spaceflight, the ballistic flight into it through outer space. On September 17, 1976, the first full scale prototype was completed.
Originally, “Enterprise” had been intended to be refitted for orbital flight, which would have been made it the second space shuttle to fly after “Space Shuttle Columbia” (NASA Orbiter Vehicle Designation: “OV-102”), the first spaceworthy Space Shuttle in NASA’s orbital fleet. However, during the construction of “Columbia,” details of the final design changed, particularly with regard to the weight of the fuselage and wings. Refitting “Enterprise” for spaceflight would have involved dismantling the orbiter and returning the sections to subcontractors across the country. As this was an expensive proposition, it was determined to be less costly to build “Space Shuttle Challenger” (NASA Orbiter Vehicle Designation: OV-0999), NASA’s second Space Shuttle orbiter to be put into service–“Columbia” having the first–around a body frame (STA-099) that had been created as a test article. Similarly, “Enterprise” was considered for refit to replace “Challenger” after the latter was destroyed–the “Space Shuttle ‘Challenger’ disaster” occurring on January 28, 1986, when Space Shuttle “Challenger” (mission STS-51-l) broke apart 73 seconds into its flight, leading to the deaths of its seven crew members. However, “Space Shuttle Endeavour” (Orbiter Vehicle Designation: “OV-105”), one of the retired orbiters of the Space Shuttle program of NASA, the space agency of the United States, was built from structural spared instead.