Next ISS Spacewalk: June 29th

Specialists in Moscow Sunday continued to analyze the cause of an unexpectedly high rate of pressure loss in the primary oxygen bottle on Astronaut Mike Fincke’s Russian space suit, which terminated Thursday’s spacewalk after 14 minutes.

Planners have retargeted the Extravehicular Activity (EVA) for no earlier than Tuesday, June 29, based on Russian ground station communication coverage. That is expected to be confirmed Monday following the next meeting of the International Space Station’s (ISS) Mission Management Team.

Almost immediately after switching their Orlan spacesuits to internal power and opening the Pirs Docking Compartment hatch to start the EVA, Fincke and Expedition 9 Commander Gennady Padalka were told to terminate the spacewalk and begin troubleshooting efforts to determine the cause of the pressure loss in the primary oxygen tank on Fincke’s suit.

Once the ISS was reconfigured for normal operations, the troubleshooting began, which stretched into today with additional evaluations focusing on an injector switch that increases the flow of oxygen into the Orlan spacesuit. The crew cycled the switch on and off several times, while observing the suit injector system’s status light.

Though investigation into the cause of the injector switch problem will continue throughout the weekend, Russian flight controllers assured the crew that its procedures were executed properly and it could expect to use the same suits when the spacewalk is rescheduled.

The objective of the spacewalk is to restore power to Control Moment Gyroscope (CMG) #2 by replacing a Remote Power Controller Module (RPCM). CMG #2 was taken off line April 21 by a failure of a circuit breaker in the RPCM. Currently, because of the failure of CMG #1 about two years ago, the attitude of the Station is being adequately controlled by the two remaining CMGs.

FMI: http://spaceflight.nasa.gov