International Space Station (ISS) crew members are activating the new Harmony pressurized node for the arrival of Europe's long-delayed Columbus laboratory module, following one final spacewalk Nov. 24 to complete external hookups on the node.

Station managers plan to meet Nov. 27 to review ISS readiness to receive space shuttle Atlantis with Columbus in its payload bay after its launch window opens Dec. 6. Highly efficient work by the Expedition 16 ISS crew appears to have made up for time lost in the tight ISS assembly schedule to solar array repair work during the most recent shuttle visit.

On their Nov. 24 extravehicular activity (EVA), Expedition 16 commander Peggy Whitson and flight engineer Dan Tani had enough time after making the final Harmony connections to pull another cover off the starboard solar alpha rotary joint (SARJ) that presents the next big challenge to station planners.

As was the case when Tani inspected a different section of the 10-foot-diameter joint Oct. 28, the pair found the geared mechanism that turns the big solar array at that end of the truss fouled with metallic shavings. Guided by questions from engineers on the ground, the two spacewalkers determined that the rotating race ring was damaged all the way across, apparently by something dragging across it.

"It's damaged," said Whitson, who took part in the inspection to familiarize herself in case she is directed to attempt additional inspections or repairs after Tani's scheduled departure on Atlantis next month.

Serious damage to the race ring could be bad news for the long-term station assembly plan. There is a backup race ring in the joint, but switching over to it will take "multiple EVAs," and until the joint is functioning normally managers want to keep the joint parked to avoid further damage.

Without the power levels generated when the SARJ is able to rotate the array through 360 degrees to get the best sunlight angle on its power-producing surface, the ISS may not be able to meet the requirements of the big Japanese Kibo laboratory now set for launch in April 2008.

Further inspection is planned during the third scheduled EVA of the upcoming STS-122/1E ISS assembly mission, and there is a chance a full inspection under all 21 SARJ covers will be possible if Atlantis can stay docked long enough for a fourth EVA.

During the Nov. 24 EVA, Whitson and Tani hoisted an 18-and-a-half-foot-long tray of ammonia cooling lines over the truss and bolted it in position across the port side of Destiny to finish linking Harmony with the station radiators on the truss. They performed a similar task on Nov. 20 on the starboard side of the modules.

The spacewalkers also finished reconnecting the station-to-shuttle power transfer system (SSPTS), which allows visiting shuttles to draw power from the station solar arrays through the pressurized mating adaptor (PMA-2) that the crew has relocated to the front of Harmony. That may help Atlantis stay docked to the station two extra days next month to begin work on the SARJ.

The crew started work outside an hour and 10 minutes ahead of schedule, and by the end of their EVA engineers at Mission Control Center in Houston already were activating cooling and other systems in Harmony. Whitson entered the node on Nov. 25 to begin internal activation there.