Early today, the crew -- Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev - powered up the Vozdukh system in Zvezda, a regenerative air-scrubbing system that removes carbon dioxide from the cabin and vents it overboard. The system has been confirmed working well by Russian flight controllers at Mission Control, Korolev, and the crew has discontinued use of disposable canisters that had initially been used to remove carbon dioxide.
The crew also installed the Elektron system, equipment that uses water to replenish the oxygen supply aboard the station. The Elektron system will be tested, but will not be used as the primary system for oxygen generation aboard the station for several weeks, until after the installation of United States-developed solar arrays by the next Shuttle mission to the complex, STS-97 to launch Nov. 30. The crew is now using about one oxygen-generating canister per day to replenish the onboard atmosphere.
The crew also successfully installed a compressor in the Zvezda air conditioning system for a test of its operation planned to take place tomorrow. The air conditioner provides some cooling in the module and also removes humidity. Even without the air conditioner operating, the average temperature aboard the station is about 75 degrees Fahrenheit and the relative humidity is estimated to be between 40-50 percent. Other equipment that the crew worked with during the day included setting up a Russian laptop computer system that is used, among other things, to track the station's inventory of equipment and supplies. In addition, the crew completed installing a central post computer today, a system that allows laptop computers to be used to monitor the operation of Zvezda systems.
Flight controllers are monitoring a potential close pass to the station by a piece of space debris being tracked by the U.S. Space Command. The latest predictions show that the debris will pass more than 2 kilometers from the station at about 12:43 a.m. Sunday. The current plan is to not perform any station maneuver to further avoid the debris.
The crew was scheduled to begin a sleep period at 1:30 p.m. CST and will awaken at 10 p.m. to begin a fourth day aboard the station. Tomorrow is planned to be primarily a day off for the crew. The crew is expected to maintain the same sleep schedule on Sunday. The normal work schedule for Expedition crews will call for five-day work weeks with weekends free. The ISS is orbiting the Earth at an altitude of about 237 statute miles with its systems in good shape.