Spacewalkers Wrap Up Space Station Service Call
Spacewalkers Chris Cassidy and Tom Marshburn exit the Quest airlock to begin the fifth and final spacewalk of the STS-127 mission on July 27, 2009.
Credit: NASA TV

This story was updated at 1:20 p.m. EDT.

Two astronauts wrapped up some final maintenance work on the International Space Station Monday during the fifth and last planned spacewalk of their mission to the orbital lab.

Spacewalkers Chris Cassidy and Tom Marshburn spent just under five hours tackling odd jobs and unfinished work outside the station during their mission's fifth spacewalk, which tied the record for the most outings performed on the orbiting lab while a space shuttle is docked at the outpost.

"We're pretty awed by this whole thing," said their crewmate Dave Wolf, spacewalking chief of NASA's astronaut office, from inside linked station and Endeavour as the spacewalk ended. "The whole team put together these five [spacewalks]. The two of you have done just an outstanding effort."

"Thanks Dave," both spacewalkers radioed back.

Monday's spacewalk marked the third career outing for both Cassidy and Marshburn and the last planned while the shuttle Endeavour is docked at the station. Cassidy took things slow and steady to avoid overtaxing his spacesuit's ability to scrub carbon dioxide from his atmosphere, which occurred on his first two spacewalks.

But despite Cassidy's deliberately slow pace, the spacewalk started at 7:33 a.m. EDT (1133 GMT) - nearly an hour early - and went swiftly as the two astronauts worked 220 miles (354 km) above Earth.

"If you go even slower, we'll get further ahead," Wolf told Cassidy while choreographing the 4-hour, 54-minute spacewalk from inside Endeavour.

Endeavour’s six-man, one-woman crew is in the home stretch of a 16-day mission that delivered a new crewmember and vital spare parts to the space station, as well as a new exterior experiment porch for the station’s Japanese-built Kibo laboratory.

Smooth spacewalk

Cassidy and Marshburn breezed through their initial chores to rewire power cables for the space station's American-built attitude control system and secure loose insulation on a Canadian-built maintenance robot. They then swiftly added a pair of television cameras to the new experiment porch that their shuttle Endeavour delivered for the station's $1 billion Japanese Kibo laboratory.

The video cameras will provide good views of Japan's new unmanned cargo ship - the H-2 Transfer Vehicle - when it makes its maiden flight to the station in September.

The astronauts completed all the tasks set for them during today's excursion, except for the installation of a cargo attachment system, which Mission Control decided would take too long to do today. Instead, the spacewalkers worked on some get-ahead tasks to fill their remaining time outside, including installing new handrails and work site attachments on the Kibo lab and attaching wire ties to some external cables.

Monday’s spacewalk was the 130th dedicated to space station construction and maintenance. Over the last 10 years, astronauts have spent 810 hours and 33 minutes - more than a full month - spacewalking to build the $100 billion laboratory.

In all, Endeavour’s spacewalking team spent a total of 30 hours and 30 minutes working outside the station during the mission’s five outings. Marshburn finished a total of 18 hours and 59 minutes of orbital work during his three spacewalks, while Cassidy wrapped up with a total of 18 hours and five minutes.

Endeavour’s other spacewalkers were astronauts Tim Kopra and Wolf. Kopra made one spacewalk and ended with five hours and 32 minutes. Wolf participated in the first three spacewalks of the flight, for a career total of 41 hours and 57 minutes over seven spacewalks in all.

The shuttle crew will undock Endeavour from the space station on Tuesday - one day before an unmanned Russian cargo ship is due at to arrive at the outpost - and return to Earth on Friday.

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  • Video - The Kibo Lab: Japan's Hope in Space - Part 1, Part 2
  • SPACE.com Video Show - The ISS: Foothold on Forever

SPACE.com is providing continuous coverage of STS-127 with reporter Clara Moskowitz and senior editor Tariq Malik in New York. Moskowitz contributed to this report.Click here for mission updates and SPACE.com's live NASA TV video feed.