Expedition 10 Commander and NASA Science Officer Leroy Chiao and Flight Engineer Salizhan Sharipov will vacate the Station briefly on Monday. After configuring Station systems for autonomous operation, they will fly their Soyuz spacecraft from one parking spot to another on the complex. To prepare for the Soyuz repositioning, Sharipov test-fired the Soyuz steering jets Wednesday. Today, the crew reviewed their plans for the brief undocking and redocking activities with ground controllers and closed the hatch between the ISS Progress 15 resupply craft and the Zvezda Service Module. Other hatches will be closed Sunday and early Monday prior to the Soyuz maneuver.
At 3:29 a.m. Central time Monday, Sharipov, the Soyuz commander, and Chiao will undock the spacecraft from a port on the Station's Pirs Docking Compartment. They will back away to a distance of about 30 meters (98 feet) and then move laterally about 14 meters (45 feet) along the Station to briefly hold position facing the nadir docking port on the complex's Zarya module. The crew will then rotate the craft to align with the new docking port, and will guide the Soyuz in for its redocking at Zarya at about 4 a.m. Central time. The move will clear Pirs for use as an airlock from which Chiao and Sharipov will conduct two Russian spacewalks early next year.
Monday's activities will be broadcast live on NASA Television beginning at 3 a.m. CST.
A thruster test conducted on Wednesday showed all systems ready for the move, although Russian flight controllers did see the same indication of a possible reduction in pressure or fuel flow from one Soyuz thruster as had been noted during the spacecraft's arrival at the complex in October. Since the abnormal indication poses no problem for the safe operation of the Soyuz on Monday or in the future, Station managers gave final approval Wednesday for the 30-minute maneuver. A further test of the same thruster originally planned during the repositioning Monday to gather more data for Russian specialists monitoring the system was canceled today by Russian managers since it involves a thruster that will not be used during Monday's procedure.
Also this week, the crew began preparations for the undocking of the Progress cargo craft attached to the Station. The crew reinstalled a docking mechanism on the resupply vehicle, which will be undocked from the complex and deorbited a few days before Christmas.
Russian managers have elected not to conduct another reboost of the Station to make up for a slight shortfall in altitude resulting from last week's firing of the Progress engines. As a result, Russian space officials are expected to move the launch of the new ISS Progress 16 resupply craft one day -- to December 24 (December 23, U.S. time) -- with a docking to the Station on December 26 (Christmas Day, U.S. time) to meet the current altitude of the complex. A final decision on the adjustment to the Progress launch date is expected early next week.
The crew took the day off Thursday in observance of the Thanksgiving holiday, enjoying packaged smoked turkey and potatoes. They also have off-duty time planned for the weekend before getting an early start Sunday evening to prepare for the Soyuz move in the wee hours Monday.