Some of the STS-90 crew members pose at the Shuttle Landing Facility hours after arrival on May 3, ending their nearly 16-day Neurolab mission. Shown left to right are Mission Specialist Richard Linnehan, D.V.M.; Payload Specialist Jay Buckey, M.D.; and Mission Specialists Dafydd (Dave) Williams, M.D., with the Canadian Space Agency and Kathryn (Kay) Hire holding a sign that states "Proud to be at KSC." The 90th Shuttle mission was Columbia's 13th landing at the space center and the 43rd KSC landing in the history of the Space Shuttle program. During the mission, the crew conducted research to contribute to a better understanding of the human nervous system KSC-98pc579

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.