Commander Eileen Collins, Pilot Jeff Ashby and Mission Specialists Cady Coleman, Steve Hawley and Michel Tognini completed work with the Southwest Ultraviolet Imaging System, a telescopic instrument mounted on the side hatch window in the middeck which has collected ultraviolet data on the moon, Jupiter and Venus. Additional work was conducted with several experiments studying the reaction of biological samples and plant growth to the absence of gravity.
Collins and Ashby fired Columbia's orbital maneuvering system engines and its reaction control system jets several times to provide more data for a pair of experiments examining how engine exhaust disturbs the molecules in the ionosphere in low Earth orbit.
Ashby, Hawley and Tognini took turns on a special treadmill set up in the middeck which was equipped with accelerometers and sensors to measure how well the device can offset vibrations induced by crew exercise. Engineering data from the treadmill may be used by technicians in the development of exercise equipment for the International Space Station designed to minimize disturbances to delicate microgravity experiments.
Tognini and Collins took time out to field questions from French Space Agency officials and students in Toulouse, France near the end of the crew's work day and Collins was joined by Ashby to discuss the progress of the mission with U.S. television networks and local television affiliates in upstate New York.
With all of Columbia's systems functioning in excellent shape, NASA managers will be discussing landing opportunities and weather forecasts for Florida in advance of the astronauts' final full day in orbit.
Current forecasts call for mostly clear skies and a possibility of thundershowers near the 3-mile long landing strip at the Kennedy Space Center for Columbia's planned touchdown tomorrow night at 10:20 p.m. Central time. A backup landing opportunity is available at the Florida spaceport 90 minutes later.
The five crew members will begin an eight-hour sleep period at 7:31 a.m. Central time this morning and will be awakened at 3:31 p.m. to begin their fifth day in space. Collins and Ashby will check out Columbia's flight control surfaces and fire the ship's reaction control system jets tonight in the routine pre-landing checkouts conducted the day before every shuttle landing, insuring that the orbiter is in good shape to support the vehicle's high-speed return to Earth.
Columbia is orbiting at an altitude of 182 statute miles with all of its systems in excellent condition.