Weather conditions had earlier forced NASA to skip two landing opportunities and were making landing at Kennedy unlikely. With only 24 hours of reserve fuel and unfavourable weather in Florida, NASA had prepared backup landing sites at Edwards Air Force Base in California and White Sands, New Mexico. Landing at Edwards would have delayed Discovery's next launch by a week, but landing at White Sands would have push back the relaunch date at least a month.
During an eight day stay at the International Space Station, Discovery's crew continued the construction of the outpost with the addition of the P5 spacer truss segment during the first of four space walks. The next two space walks rewired the station’s power system, leaving it in a permanent setup. A fourth space walk was added to allow the crew to retract solar arrays that had folded improperly.
Discovery also delivered a new station crew member and more than two tons of equipment and supplies to the station. Indian-American Sunita Williams stayed behind to beginning a six month stint on the station, replacing Germany's Thomas Reiter who spent six months in orbit.