What Are Those Guys Up To, Anyway?

The five-crew members aboard the International Space Station are busy with hand over briefings and scientific experiments following their arrival early last Wednesday. The outgoing Expedition 8 crew and incoming Expedition 9 crew held a Change of Command Ceremony Tuesday.

Expedition 9 Commander Gennady Padalka and NASA ISS Science Officer Mike Fincke docked their Soyuz spacecraft to the port of the Zarya Control Module at 1:01 a.m. EDT Wednesday April 21. They opened hatches and boarded the Station about an hour later, beginning their six-month stay.

With them on the Soyuz was European Space Agency Astronaut Andre Kuipers of the Netherlands. He will spend nine days aboard the Station conducting scientific investigations. Kuipers will return to Earth with Expedition 8 Commander Michael Foale and Flight Engineer Alexander Kaleri.

Foale and Kaleri arrived on the Station October 20, 2003. The Expedition 8 Soyuz capsule is scheduled to undock from the Pirs Docking Compartment, where it has been during their mission, at 4:52 p.m. EDT, Thursday. The landing is scheduled for Thursday night at 9:09 p.m. EDT, on the steppes of Kazakhstan.

Early last Thursday, during their Daily Planning Conference, crew members were told one of the Station's three operating Control Moment Gyroscopes, CMG 2, had gone off line at about 4:20 p.m. EDT 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 and are sufficient for controlling the Station's orientation until the RPCM is replaced. Flight controllers are planning a spacewalk. It will likely happen within the next month. Crewmen will replace the RPCM with a spare unit and restore operation of CMG-2. A spare RPCM is aboard the Station.

FMI: http://spaceflight.nasa.gov