Astronauts speed through 5th and final spacewalk

Christopher Cassidy and Thomas Marshburn got so far ahead on the flight's fifth spacewalk that they even took on extra work, a welcome change from earlier excursions that were bogged down by balky equipment and other obstacles.

"Since you guys are cruising, we're running out of tasks," Mission Control called up as the spacewalk neared the four-hour mark. Twenty minutes later came the call: "We're out of tasks."

The spacewalk ended up lasting just four hours and 54 minutes, and set the stage for shuttle Endeavour's scheduled departure Tuesday.

Compared with the previous outings, this one included a hodgepodge of relatively mundane jobs.

The spacewalkers rearranged electrical hookups for a pair of gyroscopes, giving them separate power supplies, and folded down a piece of popped-up insulation on a small robot hand at the international space station. Then they hooked up two TV cameras on the brand new porch of a Japanese lab, installed by the two crews last week. The cameras will assist in experiment work on the porch and in the docking in two months of a Japanese cargo carrier.

"Congratulations, you guys just completed the ... assembly," Mission Control radioed once the second camera was secured. Japan's enormous $1 billion lab, named Kibo, or Hope, required three shuttle flights and took more than a year to finish.

"I can verify from up close it is, indeed, a beautiful laboratory," Marshburn said.

Shuttle commander Mark Polansky had cautioned his crewmates to keep their guard up, despite the simple tasks. "In my book, the last one you do is the one that you have to watch out for the most," he noted.

Only a handful of other shuttle flights have had five spacewalks squeezed into them.

"Most shuttle crews are content with three or four," Mission Control said in a morning message. "Today, you'll be joining a very select group by doing your fifth! Thanks for going the extra mile ... or the extra 125,000 miles as the case may be."

With the spacewalk coming in under five hours, the total mileage ended up being closer to 90,000, given an orbital speed of 17,500 mph.

The five spacewalks together spanned a total of 30 hours.

Cassidy and Marshburn were so eager to get started on spacewalk No. 5 that they floated out an hour early as the linked spacecraft sped across the Atlantic, halfway between South America and Europe. Fifteen minutes later, they crossed over Italy; the toe and heel of the boot were clearly visible 220 miles beneath them.

Endeavour is scheduled to undock from the space station Tuesday afternoon, then spend three more days in orbit before returning to Earth on Friday.

The joint 1 1/2-week mission created the largest space gathering ever, with 13 people. Seven of them will be coming back on the shuttle.

Cassidy took his time, as promised, during Monday's spacewalk in order to keep his carbon dioxide levels down. His first spacewalk, last Wednesday, had to be cut short because of elevated carbon dioxide levels in his suit. He made it all the way to the end of Friday's outing, despite a slight buildup.

"If you go even slower, we'll get further ahead," astronaut David Wolf reminded Cassidy from inside.

As usual, though, Cassidy's brisk metabolic rate went through the carbon-dioxide absorber in his suit more quickly than his partner's.

That prompted Mission Control to skip one chore, the opening of a platform for big spare station parts. It would have been too time-consuming and officials, playing it safe, decided to save the job for future spacewalkers. Everyone was still "busting proud," Wolf said.

Mission Control officials say Cassidy's background as a Navy SEAL makes it difficult for him to slow down.

---

On the Net:

NASA: http://www.nasa.gov/mission(underscore)pages/shuttle/main/index.html

©2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.