Mission Specialist Rick Linnehan and Expedition 16 Flight Engineer Garrett Reisman kicked off the STS-123 mission's first spacewalk Thursday.

Cape Canaveral, Fla. ? NASA pressed ahead with the first spacewalk of shuttle Endeavour’s space station mission Thursday night despite a problem getting power to a giant robot that needs to be assembled by astronauts.

The trouble cropped up earlier in the day and had engineers scrambling for a solution.

LeRoy Cain, chairman of the mission management team, said Thursday night’s spacewalk would go off as planned and stressed that the power loss would not affect astronauts’ work to attach the robot’s hands to its 11-foot arms.

It’s too soon to know whether the second spacewalk, also dedicated to robot assembly, will be impacted if the problem persists, Cain said. Power is needed to heat the joints, limbs and all the electronics of the Canadian robot, Dextre, which could be damaged if left cold for days. It’s also needed to check out Dextre and get it moving.

“We don’t have our hair on fire and need to do something in the next couple of hours, but we’re working it,” Cain said at a late-afternoon news conference.

NASA’s space station program manager, Mike Suffredini, said he was confident the problem was understood and could be resolved fairly quickly.

Canadian engineers suspected the trouble could be with a timer and were working on a computer software patch to fix it. Other options were being considered, including relaying power to Dextre through the space station’s robot arm.

In the worst case, spacewalking astronauts could go back out to disassemble Dextre and leave it in pieces at the space station, Suffredini said. That way, the robot would not have to be heated.