Space station crew plans first space walk
The two astronauts aboard the International Space Station plan on Wednesday to make their first space walk since arriving three months ago, leaving the station unmanned to venture outside and install equipment and experiments, NASA officials said.
US station commander Leroy Chiao and Russian cosmonaut Salizhan Sharipov are scheduled to pull on Russian Orlan spacesuits and float out of the hatch at 1:27 a.m. (6:27 GMT) on Wednesday.
Chiao, who made four spacewalks during previous space flights, and Sharipov, who will be making his first, have spent more than a week preparing for the 5 1/2-hour outing.
In addition to the usual inspections of spacesuits, tools and equipment, the men have had to set up the station to temporarily operate with no one aboard.
Three-member crews used to be maintained on the space station and one person remained on board during space walks.
But after the space shuttle Columbia broke apart on reentry into the Earth's atmosphere in 2003 and the shuttle program was grounded, cargo transport has been severely curtailed and the crew cut to two to save on water, food and other supplies.
"One of the challenges of the two-person spacewalk is we don't have the third crew member inside to respond to unforeseen situations or circumstances that, although unlikely, may arse," said NASA flight director Derek Hassmann.
NASA and the Russians devised ways to give ground control teams greater oversight of the space station during spacewalks.
The crew has set up television cameras so flight controllers can watch key equipment, closed hatches and reconfigured coolant lines for greater control in case of a fire or depressurization.
The astronauts on Wednesday will install work platforms and other gear outside the station's Zvezda module and set up two commercial experiments -- a prototype robotic arm, called Rokvis, built by the German Space Agency, and a trio of canisters containing life science experiments, which will be retrieved during a future spacewalk.
Before returning to the station's airlock, Chiao and Sharipov will inspect some vents to see if they can pinpoint any debris that may be affecting the station's troubled oxygen generator.
There are many more urgent tasks pending, including replacing the station's failed gyroscope, which helps keep the outpost properly positioned without tapping its limited fuel supplies. That job will have to wait until NASA is able to return the shuttles to space, currently targeted for May.