Friday, July 24, 2009

Live in orbit: spacesuit performance monitored

Blogger update, 11:20 a.m.: Cassidy and Marshburn have installed the first battery of the day, and the third overall, on the Port 6 truss. Three more to go.

Spacewalker Chris Cassidy's spacesuit appears to be performing normally so far today, hopefully avoiding a repeat of the elevated carbon dioxide levels that cut Wednesday's spacewalk short.

"Everything looks good with the consumables, no unusual spikes," Aki Hoshide, a Japanese astronaut communicating with the crew from NASA's Mission Control Center in Houston, radioed early in the excursion.

But as Cassidy and Marshburn began removing thermal covers from a battery on a cargo palette positioned near the Port 6 truss, Hoshide warned Cassidy not to over exert himself.

He said there was no immediate concern, but "we did see some high rates a while ago."

After Wednesday's spacewalk - his first ever - Cassidy replaced a lithium hydroxide canister in his spacesuit that absorbs carbon dioxide.

Mission manages believe the canisters don't last as long if they have to work too hard early in a spacewalk.

The two spacewalkers are working at the far left end of the station's central truss, which supports four sets of solar array wings. The Port 6 truss holds the set farthest from the Quest airlock, more than 50 yards away.

Cassidy and Marshburn have removed the first of four new batteries they plan to install on the truss. The batteries store power for the U.S. Destiny lab when the station swings behind Earth and sunlight doesn't reach the P6 solar arrays.

The spacewalkers are working in tight quarters, boxed in by a large cargo palette held by the station's robotic arm, which is stretched about as far as it can go.

The palette holds four new batteries after two were installed Wednesday. It will carry home all six of the old batteries being replaced.

The old batteries have been in use since 2000, beyond their planned 6.5-year design life. Each new battery weighs 367 pounds on the ground.

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