JOHNSON SPACE CENTER, Houston--Astronauts David Wolf and Thomas Marshburn carried out a successful six-hour, 53-minute spacewalk Monday, moving critical spare parts to the International Space Station as a hedge against failures after the shuttle is retired next year.
Crewmates inside, meanwhile, repaired the toilet in the U.S. lab module after a malfunction Sunday.
The spacewalk got under way at 10:27 a.m. CDT and ended at 5:20 p.m. It was the 127th excursion devoted to station assembly and maintenance since construction began in 1998, the eighth so far this year and the second of five planned for Endeavour's crew. Total station assembly spacewalk time now stands at 792 hours and 31 minutes.
The objectives of Monday's excursion were relatively straight forward, although it took a bit longer than expected.
With his feet anchored to the end of the space station's robot arm, Wolf moved a spare KU-band antenna to the station, along with a 1,300-pound coolant system pump module and a spare motor for the robot arm's mobile transporter.
Marshburn helped out by providing clearance cues to Wolf and robot arm operator Julie Payette as the bulky components were maneuvered into position for attachment to an external stowage platform on the left side of the station's main power truss.
There were no problems, but the transfer work ran long and installation of a television camera on the newly attached Japanese Exposure Module experiment platform was deferred to a later spacewalk.
As Monday's excursion was getting under way, space station commander Gennady Padalka and Frank De Winne repaired a broken toilet in the U.S Destiny laboratory, replacing components that were contaminated during a malfunction Sunday.
After tests to make sure the complex system was operating properly, flight controllers cleared the combined 13-member shuttle-station crew to resume normal use.
The toilet broke down Sunday when chemically treated water flooded a pump and contaminated other downstream equipment. The astronauts removed access panels and replaced a half-dozen components during work Sunday and Monday.
While that was going on, the shuttle's seven-member crew was restricted to using Endeavour's on-board toilet and the six-man station crew was told to use the potty in the Russian Zvezda command module.
Going into Endeavour's mission, NASA planned for several shuttle crew members to use the toilet in the Destiny module to avoid filling up the shuttle's waste water tank.
Normally, the tank is vented overboard when it nears a full load, but that was not an option for Endeavour's crew. Docked to the front of the station near the Japanese Kibo module, the shuttle's waste water nozzle could have contaminated experiment attachment fittings on Japanese Exposed Facility.
But given the quick repair of Destiny's waste and hygiene compartment -- and assuming no other problems develop -- engineers said the shuttle waste water tank was in no danger of filling up before Endeavour undocks at the end of the mission.