Evening light begins to fade at NASA's Ames-Dryden Flight Research Facility, later redesignated the Armstrong Flight Research Center, Edwards Air Force Base, Calif. In this file photo, technicians begin the task of mounting the Space Shuttle Atlantis atop NASA's 747 Shuttle Carrier Aircraft for the ferry flight back to the Kennedy Space Center, Fla., following its STS-44 flight Nov. 24 through Dec. 1, 1991. After 38 years, the grey-colored space shuttle Mate-Demate Device at Edwards is being dismantled and demolished as a part of the final chapter in the U.S. space shuttle program. (NASA file photo)