As of about 6:30 p.m. this evening, the Shuttle trailed the station by about 70 nautical miles and was closing in by about 14 nautical miles with each orbit of Earth. The final phase of rendezvous will begin when Atlantis reaches a point about eight nautical miles directly behind the station and fires its engines in a terminal phase initiation burn at 8:39 p.m. Central.
The TI burn, as it is called, will put the Shuttle on a course directly toward the station during the next orbit of Earth. As Atlantis moves within about a half-mile of the station, Halsell will take over manual control of the Shuttle's approach, flying the Shuttle from controls in the aft cockpit. Atlantis will arrive at a point about 600 feet directly below the station about 10:09 p.m. Central, and Halsell then will begin a half-circle of the orbiting outpost. Atlantis will pass about 350 feet in front of the station and then move to a point about 250 feet directly above it about 10:34 p.m. Central.
Halsell will then begin to descend toward the station and, at about 10:38 p.m. Central, hold position at a point about 170 feet away. Halsell will maintain that distance for about 20 minutes to allow the station to move within range of Russian ground communications stations before continuing the approach. At 11:20 p.m., Halsell will hold position again briefly at a point about 30 feet from the station to ensure the Shuttle and station docking mechanisms are precisely aligned. Docking is expected about 11 minutes later with the Shuttle contacting the station at a slow rate of about a tenth of a foot per second.
During the rendezvous, Pilot Scott Horowitz will assist Halsell in controlling Atlantis' approach. Mission Specialists Susan Helms and Yury Usachev also will assist with the rendezvous and docking, with Mary Ellen Weber and Jeff Williams operating the Shuttle's docking mechanism.
After docking, a hatch leak check will be performed and the astronauts will review plans for Sunday night's scheduled space walk by Williams and Jim Voss. Atlantis' crew will not open the hatch to the Unity module and enter the station until Monday evening, 24 hours after the space walk is completed.