During the check of U.S. spacesuits, they discovered a problem with the cooling system for Commander Gennady Padalka's suit. As a result, troubleshooting and further checks are planned. The suit checkout was conducted in preparation for a spacewalk by Padalka and Science Officer Mike Fincke that will replace a failed power controller on the Station's truss. The repair is expected to restore power to a Control Moment Gyroscope (CMG) which lost power in April. Two other CMGs on the Station continue to operate well and are controlling the complex's orientation. The spacewalk is now expected to take place no earlier than June 16.
The suit checkout was planned to last about seven hours Wednesday, but it was cut short when Padalka reported no cooling. He reported small bubbles and froth in the water that is supposed to circulate through lines to provide the cooling. On Friday, Padalka and Fincke drained and replaced the water in the cooling system of Padalka's suit. On Saturday, they are scheduled to check Padalka's refilled suit cooling system to verify that water will circulate. If needed, they also may test the operation of a check valve in the system.
During the Wednesday dress rehearsal, the cooling system for Fincke's suit also experienced brief problems, but a sticky valve was quickly identified as the likely cause and it is not considered a concern for his suit's operation.
If the troubleshooting is successful on Padalka's suit, several steps remain before the spacewalk plans are finalized, including another U.S. spacesuit dress rehearsal. If needed, the spacewalk could be done in Russian Orlan spacesuits.
Also this week, Station ground controllers fired the ISS Progress 13 engines for 11 minutes, boosting the Station's altitude by 2.3 statute miles and adjusting its inclination by one one-hundredth of a degree. ISS Progress 13 is to undock from the Station at 4:19 a.m. CDT Monday, clearing the way for the arrival of the new ISS Progress 14. ISS Progress 14 is scheduled to launch at 7:34 a.m. CDT Tuesday from the Baikonur Cosmodrome in Kazakhstan. The new Progress will dock up to Zvezda at 8:55 a.m. CDT Thursday, an event that will be broadcast live on NASA Television.
In addition to fuel, food and supplies, the Progress 14 will bring new U.S. spacesuit gloves, sized specifically for Padalka and Fincke, as well as other suit components.
The crew also continued science work this week, conducting body scans using an ultrasound device. This is part of a research program to determine if minimally trained crewmembers can perform these advanced examinations with the assistance of a doctor in Mission Control. After computer-based training last week, the crew spent two sessions this week with body scans including scans of the elbow, knees, abdomen and chest.
The crew also replaced the hard drive in the Space Acceleration Measurement System, a system that provides data for a research program measuring how small vibrations may affect nearby sensitive experiments such as crystal growth studies.