Station Commander and NASA Science Officer Mike Lopez-Alegria and flight engineers Mikhail Tyurin and Thomas Reiter boarded their Soyuz spacecraft and flew it from one docking port to another. The relocation was a routine procedure conducted ahead of the launch and arrival of the next Progress supply ship, scheduled for later this month.
With Tyurin at the controls on Tuesday, the Soyuz undocked from the aft position of the Zvezda module at 3:14 p.m. EDT and docked to the Zarya control module's Earth-facing docking port at 3:34 p.m. EDT.
The 23rd Progress vehicle will launch Oct. 23 from the Baikonur Cosmodrome in Kazakhstan. It will dock to the vacated Zvezda port three days later, delivering supplies to the crew.
More than three weeks into a six-month stay, Lopez-Alegria and Tyurin are settling in to the routine of life in microgravity. They joined Reiter in celebrating his 100th day in space since his launch aboard the Space Shuttle Discovery July 4. Reiter, a European Space Agency astronaut, will return home aboard Discovery in December during the STS-116 mission. Discovery will bring NASA astronaut Suni Williams as Reiter's replacement to the station during that flight.
Oxygen is being supplied in the station cabin by tanks on the outside of the U.S. Quest Airlock while an onboard Russian oxygen-generation system, called the Elektron, is not working. Additional parts to repair the Elektron are expected to be among the supplies arriving late this month on Progress.
The station's orientation is being managed by three of the four electrically driven Control Moment Gyroscopes (CMGs). One gyroscope, designated CMG 3, was shut down after exhibiting intermittently high vibrations early Monday. Three gyros are sufficient to orient the station, and there has been no impact to the safety or operation of the station due to the shut down of CMG 3.
Flight controllers are evaluating plans for CMG 3 and any changes that might be needed to assembly operations during the December mission of Space Shuttle Discovery. During that mission alternating systems on the station will be powered off as the complex is rewired to bring online new supplies of electricity from the recently added solar arrays. Steering jets could be used to control the station's orientation if needed as gyroscopes are powered down during those procedures.
This week the crew also performed routine medical checks and took water samples while loading the docked Progress vehicle with unneeded items. Lopez-Alegria swapped a water separator in the Quest Airlock's Common Cabin Air Assembly to ensure a filter doesn't become clogged. The maintenance procedure was previously performed by the Expedition 5 crew.