After the inspection, Discovery will deploy two small scientific satellites. A third will be deployed Thursday.
Discovery Commander Mark Polansky, Pilot Bill Oefelein and Mission Specialist Nicholas Patrick will use the boom and sensor to look at thermal tiles on the shuttle’s underside. They also will inspect the reinforced carbon-carbon that protects the leading edges of the wings and the nose.
The heat shield inspection activities begin at 9:52 a.m. CST with the unberthing of the boom extension. Scanning of the heat shield with the sensor system begins at 10:52 a.m. and should take about five hours. The boom is to be reberthed into its cradle along the right side of the shuttle cargo bay at 4:22 p.m.
During the inspection, other Discovery astronauts will stow equipment in preparation for landing. Mission Specialists Bob Curbeam, Christer Fuglesang, Joan Higginbotham and Thomas Reiter will begin packing up in the shuttle’s cabin and the Spacehab module in its cargo bay.
At about 6:19 p.m. CST, the Microelectromechanical System-Based PICOSAT Inspector (MEPSI) mini-satellite will be released from Discovery's cargo bay. The coffee cup-sized satellite will demonstrate the use of tiny, low-power satellites to observe larger spacecraft. It will test the function of small camera systems and gyroscopes.
At about 7:56 p.m. CST, the Radar Fence Transponder (RAFT) satellite will be released from the cargo bay. The satellite is a student experiment from the United States Naval Academy that uses picosatellites to test the Space Surveillance Radar Fence.
All activities aboard Discovery are aimed toward a landing that would begin with a deorbit engine firing by the shuttle at 1:53 p.m. CST Friday that would lead to a touchdown at NASA's Kennedy Space Center, Fla., at 2:56 p.m. CST Friday. Mission Control continues to monitor the weather in Florida, and shuttle landing opportunities at both Edwards Air Force Base, Calif., and at White Sands Space Harbor, N.M., also will be considered on Friday.
Fuglesang and Reiter are European Space Agency astronauts. Fuglesang, from Sweden, participated in three of the four spacewalks during Discovery’s stay at the station. Curbeam set a record for spacewalks on a shuttle mission, performing four. Reiter, from Germany, is returning aboard Discovery after six months on the station.
Discovery’s crew was awakened at 6:47 a.m. by "Say You’ll be Mine," performed by Christopher Cross. It was for Reiter.
On the orbiting laboratory, Expedition 14 Commander Mike Lopez-Alegria and flight engineers Mikhail Tyurin and Sunita Williams are beginning a light-duty day after eight days of joint operations with Discovery. At 6:30 a.m. CST they were trailing Discovery by about 730 statute miles. The gap was increasing by more than 80 miles with each 91-minute orbit of the Earth.