Saturday evening, Commander Jim Halsell, Pilot Scott Horowitz and Flight Engineer Jeff Williams successfully test fired Atlantis' steering jets and verified the performance of the equipment Atlantis will use for its trip home, finding everything in good shape. Early Sunday, Halsell fired Atlantis steering jets to lower its orbit by about nine miles, a maneuver that optimizes the landing opportunities that will be available for the shuttle.
For a 1:20 a.m. Monday landing at KSC, Atlantis' orbital maneuvering system engines would be fired in a deorbit burn at 12:13 a.m. In the event weather precludes a landing on the first opportunity, a second opportunity exists for a landing in Florida on the next orbit, with a deorbit burn at 1:50 a.m. resulting in a 2:56 a.m. landing. The weather forecast for landing indicates acceptable conditions, although forecasters will be monitoring the progress of a front moving toward Florida throughout the day and its potential effect on winds at the Shuttle Landing Facility runway.
Two opportunities for a landing in Florida also are available on Tuesday and again on Wednesday, if needed. Also on Wednesday, Atlantis could land at Edwards Air Force Base, California, if required.
The crew sleep period begins at 7:11 a.m. and will end with a wake-up call from Mission Control at 3:11 p.m. Central. They will begin deorbit preparations in earnest just after 8 p.m. The shuttle's payload bay doors would be closed at about 9:30 p.m. and a go or no go decision would be made by Mission Control at about midnight in preparation for a 1:20 a.m. Monday landing.