Following the Aug. 8 docking of a Progress supply vehicle to the station, controllers pressurized the vestibule between Progress and Zvezda and conducted a successful check for leaks. The seven-member crew of STS-106 will unload supplies and equipment from the Progress into the station through the vestibule.
Propellant lines between the supply craft and Zvezda also were checked, and controllers began moving propellants -- fuel and oxidizer -- from the Progress tanks to fill those on the Zvezda module on Thursday. That fuel transfer was successfully completed. However, on Friday, during the transfer of oxidizer from Progress to Zvezda, the operation was automatically stopped due to a suspected instrumentation problem. The transfer of propellant is expected to begin again this week.
During the fuel transfer, Zvezda's attitude control thrusters were shut down for about two and a half hours due to a ground command error. The shutdown posed no problems for the station, since it is in a naturally stable orientation that requires extremely few jet firings to maintain. Further commands reestablished operation of the attitude control thrusters.
Also this week, controllers, using views from a camera on the Zarya module, confirmed that one docking target on the exterior of Zvezda had only partially deployed after launch. Although the situation has no impact on current station activities, controllers are assessing the possibility of STS-106 astronauts Ed Lu and Yuri Malenchenko deploying the target manually during a spacewalk that is already planned for the mission.
A successful test firing of thrusters on the Progress craft was performed Tuesday and changed the velocity of the station by about two miles per hour (one meter per second). A second firing is planned Thursday that will change the velocity by about nine miles per hour (four meters per second). During the next few weeks one or two more firings may be performed to fine-tune the station's position for the Shuttle's rendezvous on STS-106.
Meanwhile, at the Kennedy Space Center, Florida, Atlantis has been moved to its launch pad in anticipation of a planned Sept. 8 liftoff. At the station, Atlantis' crew will unpack the Progress and a Spacehab module in the Shuttle's cargo bay, setting the stage for the arrival of the first resident station crew this fall.
With the arrival of the Progress, the station continues a rapid expansion, now measuring 143 feet in length with a mass of 67 tons. The ISS can easily be viewed from the ground under proper lighting conditions.