Russians Look at Spacesuit’s O2 Switch

Russian specialists analyzing the cause of a loss of pressure in a spacesuit’s primary oxygen tank had International Space Station crewmembers on Friday focus on a switch that increases the flow of oxygen to the suit.

From NASA:
Russians Look at Spacesuit’s O2 Switch

Russian specialists analyzing the cause of a loss of pressure in a spacesuit’s primary oxygen tank had International Space Station crewmembers on Friday focus on a switch that increases the flow of oxygen to the suit.

The problem resulted in termination of the Thursday spacewalk a little over 14 minutes after it had begun. The spacewalk, to repair an electrical component providing power to one of four gyroscopes that control the Station’s orientation in space, is now targeted for no earlier than June 29.

Expedition 9 Commander Gennady Padalka and NASA ISS Science Officer Mike Fincke were asked to manipulate the switch several times. They also discussed the status of an indicator light in the suit’s helmet designed to show when the oxygen switch is on.

The Russian flight control team assured the crew they believed Padalka and Fincke had executed the spacewalk procedures well and did nothing that would have caused the decrease in pressure. The crew was also told to expect to use the same suits when the spacewalk is rescheduled.

The spacesuit investigation will continue through the weekend.

Official start time of the Thursday spacewalk was 5:56 p.m. EDT, when crewmembers opened the airlock hatch of the Pirs Docking Compartment in the Station’s Russian segment. But moments later, Russian flight controllers ordered Fincke back inside — Padalka was still in the airlock — after flight controllers saw the drop in pressure in the primary oxygen bottle of Fincke’s suit.

The hatch was closed again a little after 6:10 p.m. Pressure in Fincke’s suit remained stable throughout the spacewalk and he was in no danger. The official spacewalk time was 14 minutes and 22 seconds.

The goal of the spacewalk was to restore electricity to one of three functional Control Moment Gyros (CMGs). One of them, CMG 2, went off-line April 21 when it lost power. The two operating gyroscopes can control the Station’s attitude, but a third operating CMG will provide greater backup capabilities. The fourth CMG failed two years ago, and will be replaced when Space Shuttle flights resume next year.

In addition to helping with the Friday spacesuit troubleshooting, crewmembers also continued to reconfigure the station for normal operations.

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