Spacewalkers Upgrade Space Station

Two spacewalking astronauts ventured outside the International Space Station on Tuesday to install a new experiment and upgrade their orbital lab before houseguests arrive later this week.

Station commander Michael Fincke and flight engineer Yury Lonchakov spent nearly five hours toiling outside their orbital home to ready the outpost for the planned Friday arrival of seven astronauts aboard NASA?s shuttle Discovery. Discovery is poised to launch toward the station Wednesday night to deliver a new station crewmember and U.S. solar arrays.

?That?s it, we?re done,? said Lonchakov, who led the spacewalk. ?Everything is very good.?

Tuesday?s spacewalk began at 12:22 p.m. EDT (1622 GMT), just four days before Fincke?s 42nd birthday on Saturday.

?This is a great gift for my birthday,? Fincke said. Lonchakov celebrated his 44th birthday aboard the space station last week.

Their fellow station crewmate Sandra Magnus remained inside the station during the four-hour, 49-minute spacewalk. She is preparing to return home later this month aboard Discovery once her replacement - Japanese astronaut Koichi Wakata - arrives on the shuttle.

Space station clean up

The primary goal for Fincke and Lonchakov was the installation of a joint European-Russian experiment called EXPOSE-R, which the astronauts were unable to activate during a December spacewalk due to an internal cabling issue.

On Tuesday, they breezed through the experiment?s installation and Russian flight controllers successfully powered it up. The experiment will expose plant seeds, microbes and other organic and biological samples to the space environment for about 18 months, NASA officials have said.

In addition to installing EXPOSE-R, the spacewalkers repositioned a Russian materials exposure experiment and took photographs of about 28 different targets in a survey of the station?s Russian segment. They also shortened six straps near a docking port to make sure they didn?t interfere with the arrival or departure of future spacecraft.

?We?re going to do it the old-fashioned way,? Fincke said before the spacewalk. ?Yury has a knife.?

The astronauts took great care to avoid slashing open their own spacesuits while trimming the straps, and worked carefully to keep the snippets from drifting away.

?We need three hands each,? one of the spacewalkers said.

Tuesday?s spacewalk was the 120th dedicated to space station maintenance and the sixth career excursion for Fincke, who ended with 26 hours and 12 minutes of spacewalking time. It was the second spacewalk for Lonchakov, who ended with 10 hours and 27 minutes.

Russian flight controllers told Fincke that, with six spacewalks in an Orlan spacesuit, he now appears to be the leader for Americans spacewalking in the Russian-built spacesuits.

Tuesday?s excursion sets the stage for four more spacewalks by Discovery?s STS-119 astronaut crew. The spacewalks are set to start on Sunday to install a new U.S. solar arrays and starboard-side girder. Discovery is set to launch Wednesday night at 9:20 p.m. EDT (0120 March 12 GMT) from NASA?s Kennedy Space Center in Cape Canaveral, Fla.

Fincke and Lonchakov said they missed lunch during their spacewalk, but gladly traded their hunger for some fantastic views of Earth.

?There are no words in any language to describe what we?re seeing right now,? one of the spacewalkers said during a rest break. ?You see, our hard work has some positive moments to it.?

SPACE.com is providing continuous coverage of Discovery?s STS-119 mission to the space station, with reporter Clara Moskowitz at Cape Canaveral and senior editor Tariq Malik in New York. Click here for mission updates and SPACE.com's live NASA TV video feed.

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