The International Space Station (ISS) spreads its new solar wings Thursday. Spacewalking astronauts from the U.S. space shuttle Atlantis have spent two days preparing them for operation, and now they are ready to unfurl and provide extra electricity for the research complex. The astronauts had some difficulty Wednesday in their set up work.

Astronaut Dan Burbank and his Canadian colleague, Steve MacLean, ventured outside Atlantis Wednesday for the second spacewalk in two days to prepare the solar arrays for their rollout.

On Tuesday, another pair of astronauts had connected cables for power, data, and cooling, while MacLean and Burbank Wednesday removed bolts and covers that held down during launch the 17-ton girder on which the solar panels are installed.

But the crewmembers experienced some problems along the way.

"Today we had numerous battles with the hardware," said space station flight director John McCullough.  "Today it took a couple of strong folks to get the job done. I know it's not a very good analogy, but it was almost like giving birth today, the fighting we had to go through and the labor pains."

The astronauts together struggled with a balky bolt that refused to unfasten, so they retrieved a different wrench from a toolbox and slipped a long bar over the handle for extra leverage. The bolt finally loosened.

Another bolt flew away when MacLean was removing a protective cover from the rotating joint that will swivel the solar panels toward the sun. A similar bolt loss occurred during Tuesday's spacewalk. Mission officials say both bolts floated away and pose no threat to the station.

MacLean also broke a tool he was using, but he was able to grab the parts before they floated away.

Shuttle spacewalk supervisor John Haensly says mishaps like these are going to happen.

"You've got to imagine when a crewmember is in a suit, this is a pretty bulky environment they are in and to drop something - it may happen. I think you may see small problems like this happen in the future during station assembly, but we work through these and I don't see them as a big issue," he said.

After the spacewalk was over, Mission Control tested the solar array swivel joint with ground commands and confirmed that it moved.

Later Thursday, flight controllers will unfurl the solar panels slowly to their full length of nearly 80 meters. To prevent the thin mylar plastic panels from sticking together as a previous pair did, they will warm and relax them first in the sun, unfurl them half way, wait 30 minutes while the sun warms them more, and continue for the full extension.

The new arrays will double the amount of power to the space station for components to arrive in the future.