Delivered to the station a year ago, the two gold-and-blue solar wings are the largest ever flown in space, stretching 240 feet (73 meters) from tip to tip.

Big enough to cover nearly the entire length of a football field, the arrays each are held in place by four metal struts. One of the braces on the starboard wing, however, failed to latch in place when that array was deployed last December, so Godwin and Tani tried to fix it.

Since they were working in the area anyway, the idea was to use a pair of vice grips to rotate the latch on the fourth brace, but Godwin couldn't get it to budge.

"It looks like there's too much force on that shaft, and it's not going to rotate," Gorie said. "It was a really good attempt, though."

The inability to latch the brace in place was not deemed critical. NASA engineers say the starboard wing is secure with only three braces latched.

The more important task at hand was outfitting the solar wing motor drives with the thermal blankets, a job that the astronauts set out to do at 12:53 p.m. EST (1753 GMT).

Floating out of Endeavour's airlock, Godwin and Tani tethered themselves to the shuttle's 50-foot (15-meter) robot arm so that crewmate Mark Kelly could hoist them to a point about midway up the station's U.S. power tower.

"Okay guys, Mark is going to give you a ride," Gorie called out to the spacewalkers.

"Here we go," Godwin said.

The linked shuttle-station complex was flying some 243 miles (389 kilometers) above the pearl blue South Pacific Ocean at the time, approaching the northwest coast of South America.

"A beautiful Earth down there," Godwin said.

"Quite unbelievable," Tani replied. "The view is just impossible to describe out there."

Still tethered to the robot arm, the two astronauts hopped off the crane-like device and onto the U.S. power tower before climbing, hand-over-hand, another 50 feet (15 meters) up to the base of the portside American solar wing.

Working side-by-side, Godwin and Tani then unfurled a custom-made thermal blanket and wrapped it around the bulky solar array motor drive.

Crucial to keeping the power-producing wing pointed at the sun, the motor drive has been plagued by electrical spikes since early this year. The periodic bursts of current at times have caused the motor drive to stall, giving rise to concerns that it could completely seize up.

The array in that case would be incapable of tracking the sun, and if it got stuck in the wrong position, it might not be able to generate electricity at all.

NASA engineers think the problem is related to extreme temperature swings the motors are exposed to as the station passes from the sunlit to the dark side of Earth. Temperatures in a single 90-minute orbit can fluctuate between 200 degrees Fahrenheit (94 degrees Celsius) and minus 200 degrees Fahrenheit (minus 94 degrees Celsius).

The thermal blankets are expected to moderate those extremes, thus rectifying the power spike problem.

Godwin and Tani had a bit of trouble fastening the form-fitting covers on the portside motor drive. Only 11 or 12 Velcro straps designed to secure the blankets to the motor could be put in place. The astronauts had the same problem when they wrapped another thermal blanket around the motor drive at the base of the station's starboard U.S. array. But mission managers nonetheless were happy with work.

"Tell Linda and Dan they did a good job," astronaut Charlie Camarda radioed up to the shuttle from NASA's Mission Control Center in Houston.

The spacewalkers also carried out a couple of odd jobs in advance of the planned delivery of a new station truss segment next March.

They stowed a couple of circuit breakers that will be installed on the truss and retrieved several tools from stowage bags outside the station. Spacewalking astronauts will use the tools on that flight, which now is scheduled for launch aboard shuttle Atlantis on March 21.

Godwin and Tani then made their way back down the U.S. power tower and rode the shuttle robot arm back into the ship's cargo bay. And before the four-hour, 11-minute excursion was finished, the two spacewalkers caught a glimpse of their hometown from orbit.

"I see downtown Houston!" said Tani.

"Beautiful!" Godwin added.

The skies were clear enough that both could make out their suburb and both called down greetings to their spouses. Godwin's daughter, Lauren, also got an exuberant hello.

"Wow. What a fantastic day," Tani added.

Launched last Wednesday from Kennedy Space Center, Endeavour ferried a new crew up to the station and will return to Earth with an American and two Russians who have been aboard the outpost since August.

The shuttle remains scheduled to depart the station Friday, but mission managers are expected to extend the shuttle's stay at the outpost by a day.

In that case, Endeavour would head-off Saturday on a two-day trip back to NASA's costal Florida spaceport, landing here at KSC on Dec. 17.