That space walk is scheduled to begin about 10:30 p.m. Friday, pending a successful leak check of the crew lock while the crew sleeps today. Mission Specialists Mike Gernhardt and Jim Reilly will attach a fourth and final supply tank to the airlock's exterior, and move on to some get-ahead tasks made possible when they were able to attach a bonus third tank during Wednesday's space walk. Tasks added to Friday's space walk include an inspection of one of the station's solar array swivels and inspection of the Floating Potential Probe that measures plasma levels around the solar arrays.
STS-104 Commander Steve Lindsey and Expedition Two Flight Engineer Jim Voss finished replacing the Intermodule Ventilation (IMV) Assembly valve in the station's Unity module about 7:30 p.m. Wednesday. With help from station Commander Yury Usachev, they replaced the leaking valve with another from the Destiny laboratory that won't be needed until the station's second node arrives in 2003.
Voss, Mission Specialist Janet Kavandi and Susan Helms moved the hatch from its initial location between the Unity module and the airlock's Equipment Lock to between the Equipment Lock and Crew Lock. The Equipment Lock will be used for storing and servicing space suits, while the Crew Lock will serve as the exit to space.
Usachev also worked with one of the station's payload computers, performing maintenance on several of the station's Russian systems, and Kavandi, Gernhardt and Reilly worked to transfer items between the shuttle and station while getting equipment and space suits squared away in the airlock. Helms also changed out a Command and Control computer that had been temporarily installed in place of a payload data computer in Destiny. The payload computer was cannibalized during the STS-100 mission and retasked when all three of the station's command computers broke down. The old computer will be returned to Earth on Atlantis for testing and analysis.
Lindsey and Pilot Charlie Hobaugh gave the station another boost using the shuttle's reaction control system jets, increasing the station's orbit about 5 miles to 244 x 240 statute miles. It was the final reboost planned for this mission. Atlantis will leave the station later this week about 10 miles higher than when it arrived.