Astronauts Richard Linnehan and Robert Behnken wrapped up a six-hour 53 minute spacewalk early today, completing assembly of a 3,400-pound Canadian maintenance robot and moving critical spare parts from the shuttle Endeavour to the space station.

"This really was the kind of spacewalk that, when it's all done, you just want to throw your hands up in the air and howl at the moon," said Zeb Scoville, lead spacewalk officer for Endeavour's mission. "It really was a great day for us. There were a few challenges we had along the way, but I consider this a real huge success for the EVA team, for the assembly of (the robot), getting all the (spares) transferred, is just a monumental feat by the robotics team and the EVA team together."

The only problem of any significance cropped up late in the spacewalk when two suitcase-size experiment packages designed to expose a variety of materials and coatings to the space environment could not be installed on the station's hull as planned because of problems getting the first package firmly locked in place.

"Endeavour, Houston, for EVA," astronaut Steve Robinson radioed from mission control. "OK, for MISSE (Materials International Space Station Experiment), we're going to plan right now to reverse course, do your U-turn and Bob, if you would take that right back where you found it."

"OK," Behnken replied. A few moments later, inspecting the troublesome attachment fitting, he added, "I'm not sure what else I can do. You can see metal shavings..."

"Yeah, I could see the metal shavings as I went by, floating," Linnehan said. "So, you know, better look at the quality control, I guess."

"We tried those probes at KSC," Behnken remarked.

"Yeah, I remember. In the shops, and they fit then. ... Anyway, nice work for staying out so long."

This was the 107th spacewalk devoted to station assembly and maintenance since construction began in 1998 and the third of five planned for Endeavour's mission. The spacewalk ended on the 43rd anniversary of history's first spacewalk, a 12-minute excursion in 1965 by cosmonaut Alexei Leonov.

Behnken and Michael Foreman plan two more spacewalks Thursday and Saturday to replace a circuit breaker in the station's solar power truss, to test a heat shield repair tool and to mount Endeavour's heat shield inspection boom on the station for use by the next shuttle crew. If time is available, they also will inspect a massive solar array rotary joint as part of an ongoing investigation to find out what is preventing it from freely turning.

Linnehan and Behnken completed assembly of the Canadian Space Agency's special purpose dexterous manipulator, or Dextre, robot, a $209 million attachment for the space station's Canadian-built robot arm that will, in effect, give it a pair of hands and permit replacement of faulty components that might otherwise require a spacewalk.

The spacealkers attached a camera system and a post to hold components being installed or removed. Dextre was assembled on the same Spacelab pallet that was used to carry its components into space inside Endeavour's cargo bay. Early today, the robot was pulled off the assembly pallet and maneuvered to an overnight park position. This evening, the robot will be moved to a mounting fixture on the hull of the Destiny laboratory module.

"SPDM is in its final assembled configuration," lead station Flight Director Dana Weigel told reporters early today. "We ended up leaving two of the (thermal) blankets on it. We don't think that'll be problem (but) we will have to remove those on some future EVA."

Along with completing Dextre's assembly, Linnehan also moved to direct current switching units, or DCSUs, to an external storage depot on the station, along with a spare robot arm yaw joint. While he was moving the spares, Behnken was attempting to install the first materials exposure package on a platform installed on the outboard end of the Columbus lab module. It's not yet clear whether Behnken and Foreman might make another attempt to install the experiment packages later in the mission.

Other than that one snag, the spacewalk went smoothly. The astronauts fell a bit behind schedule early on with Dextre, but they were able to make up most of the lost time. Toward the end of the excursion, Behnken reported a tear in the outer covering of an overglove. The overgloves are now routinely used to protect spacesuit gloves from damage.

"OK, MIke, glove inspection," Behnken called. "I do have, on my left hand, on the overglove, I do have a large piece of RTV that's starting to peel off. I don't see any damage underneath it to the Vectran. But there is a tear in the RTV, there's just a big flap, it's over an inch long. It was delaminated before when we came out, but now it's split all the way through. There's no visible damage on the fingers. And on my right hand, also RTV is coming off of the overglove, but the fingers look pretty good.

Glove damage is a recurring problem for station assembly spacewalkers.

Additional coverage for subscribers:
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VIDEO: INSIDE MISSION CONTROL DURING LAUNCH PLAY
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VIDEO: CREW INTERVIEW: MS4 RICK LINNEHAN PLAY

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