Endeavour astronauts complete third spacewalk

(CNN) -- Astronauts from the shuttle Endeavour completed their third spacewalk Saturday after nearly seven hours working on a joint that helps generate power for the international space station.

Heidemarie Stefanyshyn-Piper and Steve Bowen cleaned and lubricated the starboard Solar Alpha Rotary Joint, which is designed to allow the solar panels on the left side of the station to rotate and track the sun.

"We stayed at a very steady, even pace and got everything done we'd planned," John Ray, lead spacewalk officer, said at a news conference at Johnson Space Center in Texas on Saturday.

The astronauts also removed and replaced several trundle bearing assemblies.

The spacewalkers have cleaned about 330 of 360 degrees of the starboard SARJ. When they complete the starboard side, they will start on the port side, Ray said.

The spacewalkers wanted to continue working Saturday to finish the starboard side, Ray said, but mission controllers chose to end for the day.

The fourth and final spacewalk of the 15-day mission, which launched November 14, is scheduled for Monday.

The SARJ has been in limited use since 2007, when flight controllers detected increased power consumption and vibration as it moved the 240-foot solar wings to follow the sun.

Astronauts soon determined that the gear assembly was full of metal shavings, a sign that metal is grinding on metal.

Since then, cleaning and lubing the SARJ have been a major focus of this mission, along with expanding the living space to accommodate a crew of six, NASA said.

Additions to the station's living space include more places to sleep, another bathroom, an improved water system, new exercise equipment and a bigger refrigerator.

The shuttle also brought from earth a Thanksgiving dinner of irradiated turkey, candied yams, stuffing and dessert.

Inside the station Saturday, the rest of the shuttle and station crew transferred supplies and equipment between the two spacecraft, NASA said.

The crew also continued work on the Water Recovery System and a Urine Processor Assembly, which is designed to convert urine and sweat into water, flight director Ginger Kerrick said.

The Urine Processor Assembly shut down during initial tests Thursday and Friday morning. On Saturday, crew members were able to generate a sample from the Urine Processor Assembly, and that troubleshooting will continue Sunday, Kerrick said.

The mission has gone according to plan, despite a minor interruption on the first spacewalk.

A grease sun in Stefanyshyn-Piper tool's bag leaked, coating everything inside with a film of lubricant. While she was trying to clean it up in the absence of gravity, the whole bag floated away.

Stefanyshyn-Piper was able to share tools with Bowen, and NASA mission controllers expressed confidence that the lost tool bag would not be too much of a problem for the duration of the spacewalk.

Mission controllers were also tracking the lost bag, which they say is floating well clear of the station and drifting farther away.