During the U.S. spacewalk, Yurchikhin and Anderson will jettison a support post for an exterior video camera and a 1,400-pound, refrigerator-sized tank that is no longer needed. The tank, known as the Early Ammonia Servicer, was designed to replenish ammonia to the temporary cooling system on the station in the event of a coolant leak.
The spacewalkers also will replace a faulty Remote Power Control Module to restore backup power to the station's Mobile Transporter railcar, which is needed for the STS-118 mission. Other tasks include cleaning the Unity node's nadir Common Berthing Mechanism seals for the relocation of Pressurized Mating Adapter-3. PMA-3 must be moved before the station's Harmony node arrives on shuttle mission STS-120, which is targeted for late October.
Yurchikhin and Kotov worked on the Russian computers during the past week, visually inspecting and photographing cables and connectors on the command processing unit. Although there is no conclusive evidence of what caused the problems during shuttle Atlantisí visit last month, the inspections did yield some valuable information. The voltage readings on cables and connectors for the secondary power system appeared normal with the exception of one relay. Also, some corrosion was found on a second connector and a third was discolored. Troubleshooting continues.
In addition, the crew and flight controllers completed software upgrades this week for computers on the U.S. and Russian segments. The upgrades to the U.S. computers will allow the addition of the Harmony node, the European Space Agency's Columbus module and the Japanese Kibo Experiment Module during upcoming shuttle flights.
Plans are proceeding for the launch of the next Russian cargo ship, the ISS Progress 26, which will deliver to the station new computers, equipment, food, fuel, water and other supplies. Launch is scheduled for Aug. 2, with docking planned on Aug. 5.
Also this week, Anderson discussed the progress of his mission and life aboard the station during an educational in-flight event with students at the Clay Center for Arts and Sciences in Charleston, W.Va.