Astronauts Perform Fifth Spacewalk at Station

This story was updated at 1:20 a.m. EDT, March 23.

HOUSTON - Two astronauts floated outside the International Space Station (ISS) Saturday on a record fifth spacewalk for their mission, this one aimed at transferring a shuttle inspection boom to the orbiting lab?s exterior.

Spacewalkers Robert Behnken and Mike Foreman used their spacesuit-clad hands to snatch the shuttle Endeavour?s 50-foot (15-meter) sensor-tipped boom from the tip of a robotic arm and attach it to the station for a later orbiter flight.

?You?re a gladiator,? astronaut Rick Linnehan, who choreographed the spacewalk, told Foreman from inside Endeavour after playing a clip from the film "Gladiator" during the six-hour, two-minute excursion.

The spacewalkers worked in concert with robotics operators inside Endeavour and the ISS to move the shuttle?s heat shield-scanning boom between the crane-like appendages of the orbiter, station and the flesh-and-blood arms of the astronauts themselves.

Endeavour astronauts used the laser and camera-tipped inspection boom to scan their shuttle?s heat shield just after launch, then again on Friday, for damage during their planned 16-day spaceflight.

NASA has launched the 50-foot (15-meter) booms on every shuttle flight since the 2003 Columbia accident to ensure orbiters are safe to land.

But Endeavour?s sister ship Discovery can?t carry the tool when it launches May 25 because its cargo, Japan?s massive Kibo laboratory module, fills up the entire payload bay. So that shuttle?s crew will use Endeavour?s once they arrive at the space station, mission managers said.

Behnken and Foreman attached a vital power cable to the inspection boom to keep its delicate sensors warm during the two months before Discovery?s launch.

They began their spacewalk - the fifth and last planned for their record12-day stay at the space station - nearly an hour early at 4:34 p.m. EDT (2034 GMT). The excursion marked the most ever for a visiting shuttle crew at the space station, though astronauts have performed five spacewalks on service calls to the Hubble Space Telescope.

Station?s jinxed joint

With Endeavour?s boom tucked into its new perch, Foreman went on to inspect an ailing solar array joint on the station?s starboard side.

The massive, 10-foot (3-meter) wide joint is designed to rotate the station?s starboard solar wings like a paddlewheel to track the sun and maximize power production. But astronauts discovered metal shavings and damage in the joint last October, and have surveyed it several times during spacewalks to identify the source.

Foreman took a close look at an apparent ding discovered during an earlier inspection.

?I feel like this is a divot,? Foreman said, as he passed a wipe cloth over the area. ?I feel a little roughness as I rub it over there, it doesn?t feel like a protrusion.?

Foreman photographed the divot, as well as the views under several under protective covers along the joint.

?You?re doing great with that camera, Mike,? said ISS flight engineer Garrett Reisman from inside the station. ?We?re going to hire you to do my cousin?s bar mitzvah."

ISS flight director Dana Weigel said Foreman?s inspection found no sign of any debris strike the joint?s protective covers, which will allow engineers on Earth to narrow their search for the damage source and come up with repair options, if required.

?The first decision point is going to be the end of March,? Weigel said after the spacewalk, adding that the joint can be moved intermittently for the time being. ?Our current predictions show that we?re good for the next couple of flights.?

While Foreman tackled the joint inspection, Behnken used a hammer to force a stubborn materials exposure experiment in place outside the station?s European-built Columbus laboratory. Mission Control applauded his efforts and suggested his nickname be switched from ?Bam Bam? to ?Thor.?

"Alright! Bam Bam, Thor, whatever it takes,? Behnken said. ?We're here to serve.?

Saturday?s excursion marked the 109th spacewalk outside the ISS and the third career outings for both Behnken and Foreman.

Behnken ended the orbital work with 19 hours and 19 minutes of spacewalking time, while Foreman concluded with 19 hours and 34 minutes. Endeavour?s entire spacewalking team, which included Reisman and astronaut Rick Linnehan, spent a total of 33 hours and 28 minutes working outside the station during their five spacewalks.

Commanded by veteran shuttle flyer Dominic Gorie, Endeavour?s STS-123 crew is in the homestretch of a packed construction mission. The astronauts have delivered a new crewmember, Japanese storage module and the Canadian-built Dextre maintenance robot during their mission.

Endeavour is slated to undock from the station late Monday and return to Earth Wednesday evening.

NASA is broadcasting Endeavour's STS-123 mission live on NASA TV. Click here for SPACE.com's shuttle mission coverage and NASA TV feed.

• VIDEO: Space Station's Dextre Robot, AKA 'Gigantor'
• IMAGES: Launch Day for Shuttle Endeavour
• NEW IMAGES: Space Shuttle Snapshots from STS-122