Viewed from the rear, the orbiter Atlantis heads toward the open doors of the Orbiter Processing Facility bay 3 after being towed from the Shuttle Landing Facility. The blue lines represent the orbiter’s turning lines into and away from bay 3. The unusual silhouette of the aft section on the orbiter is due to the tail cone covering the aft engines. Atlantis landed Feb. 19 at Edwards Air Force Base concluding mission STS-98. The orbiter returned to Florida on the back of a Shuttle Carrier Aircraft, known as a ferry flight, that began March 1. Unfavorable weather conditions kept it on the ground at Altus AFB, Okla., for several days until it could return to Florida. Atlantis will be prepared in the OPF for mission STS-104, the 10th construction flight to the International Space Station, scheduled to launch June 8 KSC01padig139

The Space Shuttle program was the United States government's manned launch vehicle program from 1981 to 2011, administered by NASA and officially beginning in 1972. The Space Shuttle system—composed of an orbiter launched with two reusable solid rocket boosters and a disposable external fuel tank— carried up to eight astronauts and up to 50,000 lb (23,000 kg) of payload into low Earth orbit (LEO). When its mission was complete, the orbiter would re-enter the Earth's atmosphere and lands as a glider. Although the concept had been explored since the late 1960s, the program formally commenced in 1972 and was the focus of NASA's manned operations after the final Apollo and Skylab flights in the mid-1970s. It started with the launch of the first shuttle Columbia on April 12, 1981, on STS-1. and finished with its last mission, STS-135 flown by Atlantis, in July 2011.