The second time is the charm for two International Space Station (ISS) spacewalkers. Thursday night the Expedition 9 crew restored power to a key control system, completed a series of bonus jobs to get ahead on future work, and even finished up ahead of schedule.
The spacewalk went smoothly from the moment NASA ISS Science Officer Mike Fincke and Commander Gennady Padalka exited the airlock hatch, starting outside 20 minutes early. It was the second spacewalk for the two. An initial attempt was halted last week after only a few minutes due to a balky spacesuit oxygen control handle on Fincke’s suit. Last night, Fincke and Padalka spent five hours and 40 minutes outside of the Station. The spacewalk was expected to last about six hours.
The two space-age electricians completed their primary task, that was to install a new circuit breaker to restore power to one of four U. S. gyroscopes that help orient the orbiting laboratory. Mission Control in Houston confirmed the gyroscope had power and appeared to be operating well a few minutes later. It’s expected to be restored to full operation, assisting in controlling the Station’s orientation, as early as this afternoon.
Communications with the ground and between the two spacewalkers were constant throughout the night. As expected, backup communication plans that were prepared just in case, including hand signals, were never needed.
This was the first time that the primary control of a spacewalk had transitioned between flight controllers in Moscow and Houston. All Station systems operated flawlessly in an autonomous configuration while both crewmembers were outside.
Padalka and Fincke left the Station at 5:19 p.m. EDT. The duo moved smoothly from the Russian Pirs airlock along a 50-foot-long cargo crane and a series of handrails, and reached the American-built segments of the outpost at 6:09 p.m. EDT. At that time, primary control of the spacewalk transferred from Mission Control in Moscow, to Mission Control in Houston.
Flight controllers in Houston helped guide the spacewalkers to their worksite on the starboard truss structure and monitored their progress in replacing a Remote Power Control Module (RPCM) that had failed April 21.
By 7:52 p.m. EDT, Padalka and Fincke had swapped the faulty circuit breaker with a working unit. Fifteen minutes later, Spacecraft Communicator Rex Walheim conveyed the good news that power had been restored to the gyroscope. The gyroscope was tested to a speed of 30 revolutions per minute as a preliminary verification of its health. It is scheduled to be spun up to 6,600 rpm tomorrow, its normal operating speed, and brought on line to assist in stabilizing the Station.
Fincke and Padalka cleaned up tools and headed back to the Russian segment of the Station and by 9:11 p.m. EDT. Upon returning to the Pirs airlock, the spacewalkers completed get-ahead tasks that had been planned for future spacewalks. They installed two flexible handrails, mounted a contamination monitor to measure Station thruster exhaust, and added end caps to two circular handrails on the airlock.
The crew closed the hatch and ended the spacewalk at 10:59 p.m. EDT. This was the 54th spacewalk in support of ISS assembly and maintenance, the 29th staged from the Station itself. It was the fourth spacewalk for Padalka in his career and the second for Fincke.
Information about crew activities on the Space Station, future launch dates, and Station sighting opportunities from Earth, is available on the Internet at:
http://spaceflight.nasa.gov/
Details about Station science operations are available on an Internet site administered by the Payload Operations Center at NASA’s Marshall Space Flight Center in Huntsville, Ala., at:
http://scipoc.msfc.nasa.gov/