Expedition 9's Commander Gennady Padalka and NASA ISS Science Officer Mike Fincke docked their ISS Soyuz 8 spacecraft to the nadir port of the Zarya Control Module at 12:01 a.m. CDT Wednesday. They opened hatches and boarded the station about an hour later, beginning a six-month stay.
With them on the Soyuz was European Space Agency Astronaut Andre Kuipers of the Netherlands, who will spend nine days aboard the Station conducting scientific investigations. Kuipers will return to Earth with Expedition 8's Commander Michael Foale and Flight Engineer Alexander Kaleri. Foale and Kaleri arrived on the Station last October 20.
Their ISS Soyuz 7 capsule is scheduled to undock from the Station's Pirs Docking Compartment, where it has been during Expedition 8's stay on the Station, at 3:52 p.m. CDT April 29. The landing is scheduled for 7:10 p.m. CDT the same day on the steppes of Kazakhstan.
Early Thursday, during their Daily Planning Conference, crewmembers were told that one of the Station's three operating Control Moment Gyroscopes, CMG 2, had gone off line at about 3:20 p.m. CDT on Wednesday. The CMGs use power from the solar arrays to control the Station's orientation. Flight controllers traced the problem to a Remote Power Controller Module (RPCM), a kind of remotely controlled circuit breaker, that had malfunctioned and cut off power to the gyroscope. The RPCM is mounted on the top of the Station's central truss segment, above the U.S. Laboratory Destiny.
Two CMGs continue to operate well and are sufficient for controlling the Station's orientiation until the RPCM can be replaced. Flight controllers have begun planning a spacewalk that will likely be conducted sometime in the next month to replace the RPCM with a spare unit and restore operation of CMG-2. A spare RPCM is aboard the Station.