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. Tonight, Fincke and Padalka spent five hours and forty minutes outside of the Station.
The two space-age electricians completed the primary task -- installing a new circuit breaker to restore power to one of four gyroscopes that help orient the complex -- an hour ahead of schedule. Mission Control confirmed the gyroscope had power and appeared to be operating well a few minutes later. It is expected to be restored to full operation, assisting in controlling the Station's orientation, as early as Thursday afternoon.
Communications with the ground and between the two spacewalkers were constant throughout the night. Backup hand signals were never needed. It was the first time that the primary control of a spacewalk had transitioned between controllers in Moscow and Houston periodically in a well-choreographed operation that was conducted seamlessly. All Station systems operated flawlessly in an autonomous configuration while both crew members were outside during the spacewalk.
Padalka and Fincke left the Station at 4:19 p.m. CDT. 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 modules of the outpost at 5:09 p.m. CDT. At that time, primary control of the spacewalk transferred from Mission Control, Moscow, to Mission Control, 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 6:52 p.m. CDT, 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 planned to be spun 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 8:11 p.m. CDT, Mission Control, Houston, handed primary coordination back to Mission Control, Moscow. 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 9:59 p.m. CDT. This was the 54th spacewalk in support of Station assembly and maintenance, the 29th staged from the Station itself, the fourth for Padalka in his career and Fincke's second.