In the Operations and Checkout Building, the STS-101 crew gathers for a snack before suiting up for launch for the third time. The previous two launch attempts were scrubbed due to high cross winds at the Shuttle Landing Facility. From left are Mission Specialists James S. Voss, Susan J. Helms and Jeffrey N. Williams; Commander James D. Halsell Jr.; Pilot Scott J. Horowitz; and Mission Specialists Mary Ellen Weber and Yury Usachev of Russia. The mission will take the crew to the International Space Station to deliver logistics and supplies and prepare the Station for the arrival of the Zvezda Service Module. Also, the crew will conduct one space walk. This is the third assembly flight to the Space Station. After the 10-day mission, Atlantis is expected to land at KSC May 6 at about 12:03 p.m. EDT KSC00pp0576

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.