The Atlantis astronauts have successfully completed the checkout of critical landing systems, and the weather forecast is favorable for the planned landing Thursday of NASA's 135th and final shuttle mission.
Flying more than 200 miles above the planet, the astronauts fired up Auxiliary Power Unit No. 1 on the shuttle and tested the ship's flight control system, which include the ship's wing flaps and rudder speedbrake. A test of the shuttle's 44 nose-and-tail steering jets followed before the astronauts deployed a small solar science satellite.
Forecasters, meanwhile, are calling for good conditions at Kennedy Space Center for the planned 5:56 a.m. landing Thursday of Atlantis and the nation's final four shuttle astronauts -- mission commander Chris Ferguson, pilot Doug Hurley, mission specialist Sandra Magnus and mission specialist Rex Walheim.
Relatively clear skies and good visibility is expected for the shuttle's return to Earth. No flight rules violations are in the forecast.