DiscoverySpace Shuttle Discovery lifts off on the shortest shuttle flight since the 1981 test flights, lasting only three days. A classified Defense Department payload is delivered to orbit, with the help of the first Inertial Upper Stage booster developed by the U.S. Air Force. This mission is the first time that shuttles had to be swapped out prior to flight – thermal tile issues on Challenger prevented that shuttle from being used for this mission – as well as the first instance of a shuttle launch scrubbed because of concerns over freezing weather and ice at the launch site. Discovery returns via the Kennedy Space Center runway, with Commander Ken Mattingly, Pilot Loren Shriver, mission specialists Ellison Onizuka and James Buchli, and payload specialist Gary Payton aboard.