Six shuttles were built. The first shuttle orbiter, Enterprise, was constructed for test purposes and was never launched into orbit. It proved capable, however, of lifting off and gliding down to a safe landing. The first shuttle orbiter to be launched into space was Columbia, piloted by astronauts John Young (1930-) and Robert Crippen (1937-), launched for the first time on April 12, 1981, and landed safely on April 14. It was followed by Challenger on April 4, 1983; Discovery on August 30, 1984; Atlantis on October 3, 1985; and Endeavour on May 7, 1992.