The overheating is believed to have melted a rubber seal, causing a small amount of smoke, a strong odor and possibly releasing a small amount of a chemical irritant.
Aboard the station are Expedition 13 Commander Pavel Vinogradov, Flight Engineer and NASA Science Officer Jeff Williams and Flight Engineer Thomas Reiter of the European Space Agency. At the time of the problem, Vinogradov was working with the Russian Elektron oxygen generator, a device that recycles wastewater on the station into oxygen for the cabin air. The Elektron had been shut off for nine days as planned during the joint operations by the station and the Space Shuttle Atlantis.
At the request of Russian flight controllers, Vinogradov attempted to restart the unit at about 2 a.m. CDT. The Elektron operated only briefly before shutting down. Several subsequent attempts were made to restart the device in various modes. Just before 6 a.m. CDT, Vinogradov restarted the unit again after it had shut down.
A few minutes later, as the station was out of communications with the ground, Vinogradov noted the Elektron overheating, light smoke and a bad odor. When the station moved into communications, at about 6:16 a.m. CDT, Mission Control asked the crew to manually initiate a fire alarm onboard to allow software to automatically shut down ventilation fans between the station modules. Flight controllers also checked for contaminants in the cabin air and found only low levels that posed no danger to the crew. However, the crew was asked to briefly don surgical masks, goggles and gloves to protect against possible irritation by a chemical used in the Elektron, potassium hydroxide, that may have leaked.
Vinogradov reported that a small amount of clear liquid had leaked from an apparently damaged seal on the Elektron and cleaned it up, sealing it in airtight bags. Within an hour, the crew had powered back on all station ventilation equipment and had returned to working on normal activities.
The incident will not affect plans to undock a Progress cargo craft from the station tonight and the docking of the next station crew with the complex, set for 12:24 a.m. CDT on Wednesday, Sept. 20.
Expedition 14 Commander Michael Lopez-Alegria, Soyuz Commander Mikhail Tyurin and Spaceflight Participant Anousheh Ansari lifted off at 11:09 p.m. CDT Sunday from the Baikonur Cosmodrome in Kazakhstan bound for the station. Their Soyuz spacecraft is in excellent condition.
Meanwhile, the crew of the Space Shuttle Atlantis -- Commander Brent Jett, Pilot Chris Ferguson and Mission Specialists Joe Tanner, Dan Burbank, Heide Stefanyshyn-Piper and Steve MacLean -- are continuing preparations for a return to Earth. The crew completed a late inspection of the heat shielding on the nose and wings of the shuttle today using a laser scanning system. They are scheduled to land at the Kennedy Space Center at 4:59 a.m. CDT Wednesday. They began a sleep period at 1:15 p.m. CDT and awaken at 9:15 p.m. CDT for what is planned to be their final full day in orbit.