Friday, April 09, 2010

Spacewalkers stay on schedule, start "get-aheads"

Now in the tail end of their spacewalk, Discovery astronauts Rick Mastracchio and Clay Anderson have successfully moved an ammonia coolant tank and retrieved experiments from outside the International Space Station's Japanese lab.

Mastracchio now is replacing a failed box of gyroscope sensors that help the station control its position. He's located inside the center most segment of the station's football field-length truss, the outpost's structural backbone.

Earlier, he unbolted a small case (left) holding experiments known as MPAC/SEED -- Micro-Particles Capture/Space Environment Exposure Device -- and returned it to the Quest airlock. MPAC collected micrometeoroid particles, SEED exposed materials to space.

Anderson has moved on to one of the get-ahead tasks added to today's timeline after managers eliminated work on solar array batteries at the far left end of the truss, due to concerns about the potential for a static electric shock.

"Here's where our (spacewalk) goes different, so we just wanted to say, 'Slow down,'" radioed mission specialist Dottie Metcalf-Lindenburger, who is assisting the spacewalkers from inside Discovery.

Anderson will release clamps on a Flex Hose Rotary Coupler, which helps distribute ammonia through the station's coolant system. That will make it easier to replace if necessary.

This morning's spacewalk began at 1:31 a.m. and was scheduled to end around 8 a.m., but the crew has been running ahead of schedule slightly.

While the spacewalkers continued to work, Discovery pilot Jim Dutton and mission specialist Stephanie Wilson used the station's robotic arm to steer an ammonia tank to a temporary home on a spare parts platform. It is scheduled to be installed on the next spacewalk Tuesday.

And work is ongoing inside the station, flight engineer Soichi Noguchi tweeted: "Outside the station, the first spacewalk is going on. Inside the station, we moved four racks from MPLM to ISS. Big moving day!"

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