Astronauts eager for longest construction flight

Other tasks
In addition to delivering the Japanese module and Dextre, which is designed to replace spacewalking astronauts for some of simpler ISS exterior maintenance tasks, Endeavour's crew will test a shuttle heat shield repair technique that uses a caulk gun-like tool to squirt a pink, heat-resistant goo into damaged tiles to see how it behaves in space.

The repair method, one of several developed after heat shield damage led to the 2003 loss of seven astronauts aboard Columbia yet to be tested in space, has not yet been tested in the weightless vacuum of space. Engineers have found that bubbles in the material tend to rise to the top during vacuum chamber runs on Earth and expect some bubbling during the orbital test.

"I would be very surprised if we had something that was totally unexpected," NASA's space program chief John Shannon told reporters.

Spacewalkers will also return to the space station's ailing starboard solar wing joint, a 10-foot wide gear contaminated with metallic grit that has hindered its ability to rotate outboard solar arrays like a paddle wheel to track the sun. While NASA engineers believe the glitch can be repaired late this year without affecting ongoing construction, they hope to complete a full inspection of the gear that began in late October.

During the mission's fifth spacewalk, astronauts will also store Endeavour's sensor-tipped inspection boom used to scan their shuttle's heat shield for any signs of damage after launch and before landing. The astronauts will conduct a modified pre-landing heat survey while docked at the station before stowing the boom for the shuttle Discovery, which is unable to carry its own boom in addition to the Kibo lab's massive, tour bus-sized main segment when it launches in late May.

Orbital traffic
NASA hopes to launch Endeavour on either March 11 or March 12, before having to stand down for the launch of a navigation satellite atop an unmanned Delta 2 rocket. The shuttle must fly before March 23 to complete its mission in time for Russia's planned April 8 launch of a Soyuz rocket carrying the station's next crew and South Korea's first astronauts.

But before Endeavour lifts off, European space officials hope to launch Jules Verne on a shakedown cruise that will eventually end with an early April docking at the ISS. The mission was initially slated to launch late March 8 ET, but ESA officials delayed the space shot by 24 hours earlier today to allow final checks on the spacecraft.

Kirk Shireman, NASA's deputy ISS program manager, said ESA will attempt to launch Jules Verne on March 9 and March 10, but would stand down on Endeavour's launch day to clear communication satellite traffic for the shuttle's liftoff.

"We're thinking about launching an air traffic control here pretty soon just to keep it all straight," Shireman said.

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