Space ShuttleSpace Shuttle Columbia lifts off on the 80th shuttle flight, a science mission lasting nearly 18 days. Two free-floating experiment platforms are deployed and then retrieved by the end of the mission for delivery back to Earth. Two spacewalks to test space station construction techniques are called off for safety reasons when a problem arises with Columbia’s airlock. Aboard Columbia for her 21st flight are Commander Kenneth Cockrell, Pilot Kent Rominger, and mission specialists Tammy Jernigan, Thomas Jones and Story Musgrave.