Commander Brian Duffy, Pilot Pam Melroy and Mission Specialists Leroy Chiao, Bill McArthur, Jeff Wisoff, Mike Lopez-Alegria and Koichi Wakata began their day shortly after 5 a.m. Central time, preparing shuttle systems for their linkup to the new station at about 12:46 p.m. Central time.
As of about 6:45 this morning, the shuttle trailed the station by about 650 statute miles and was closing in by about 300 miles with each orbit of the Earth. The rate of closure will slow dramatically, however, as Duffy and Melroy conduct a series of jet firings to place the shuttle directly below the station late this morning for the final phase of its approach for docking. The final major maneuver, called the Terminal Initiation burn, will occur when Discovery reaches a point about eight nautical miles directly behind the station.
As Discovery moves within about a half-mile of the station, Duffy will take over manual control of the shuttle's approach, flying the shuttle from controls in the aft cockpit. Discovery will arrive at a point about 600 feet directly below the station about 10:38 a.m. Central, and then will begin a half-circle of the orbiting outpost. Discovery will pass about 350 feet in front of the station and then move to a point about 250 feet directly above it about 11:05 a.m. Central.
Duffy will then begin to descend toward the station and, about 11:15 a.m. Central, hold position at a point about 170 feet away. Duffy will maintain that distance for almost one hour to allow the station to move within range of Russian ground communications stations to monitor the shuttle's approach and docking. At 12:34 p.m., Duffy will hold position again briefly at a point about 30 feet from the station to verify the shuttle and station docking mechanisms are precisely aligned. Docking is expected about 12 minutes later with the shuttle contacting the station at a slow rate of about a tenth of a foot per second. At the time of docking, the ISS and Discovery will be flying over the Ukraine.
The shuttle's KU band communications system remains inoperative as engineers continue to review data regarding its sudden loss yesterday. Although there is no conventional television available from Discovery, the loss of the KU system has no impact to mission objectives.
Discovery is currently orbiting at an altitude of about 190 statute miles, circling the Earth every 90 minutes.