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.

Endeavour's astronauts, meanwhile, got some good news: The object that appeared to strike the shuttle's nose right at liftoff Tuesday, possibly a bird, actually missed the spacecraft altogether. Endeavour's thermal shielding looks to be in good shape for re-entry in two weeks, Mission Control informed them.

In orbit, astronauts Richard Linnehan and Garrett Reisman geared up for the first of five spacewalks planned during Endeavour's unusually long stay at the space station.

Their wakeup call late Thursday afternoon — the Bay City Rollers' "Saturday Night" — was intended to get them in the spacewalk spirit.

"It gets us all pumped up and we're ready to go out the hatch and do it all, have a ball, S-A-T-U-R, Saturday night!" called down Reisman, who will be making his first spacewalk. He rode up on Endeavour and moved into the space station early Thursday, shortly after the two craft linked up.

Besides hooking up Dextre's hands, Reisman and Linnehan will help attach a Japanese storage compartment to the space station. The compartment is the first part of Japan's massive Kibo lab, which means "hope." The main part of the lab won't arrive until May.

Dextre — which cost more than $200 million — is one of the Canadian Space Agency's main contributions to the space station. It rode up on Endeavour in nine pieces, all of them attached to a transport bed. That transporter, or pallet, was unloaded from the shuttle early Thursday and attached to the railway system on the space station for the Canadian-built robot arm.

The 3,400-pound robot, when assembled, is 12 feet high and has a shoulder span of nearly 8 feet. It's designed to help spacewalkers with some of their more routine maintenance chores, with the eventual goal of reducing the amount of time astronauts spend outside.