Today's wake-up song for Endeavour's astronauts: U2's "City of Blinding Lights."The song was selected for Shane Kimbrough, a rookie astronaut and spacewalker who credits visits to grandparents in Mims for sparking his early interest in space.
"We're looking forward to another great day in space," Kimbrough told ground controllers in Houston.
Kimbrough will serve as choreographer today for the first of the mission's four planned spacewalks, which will start repair work on a key piece of station hardware.
Lead spacewalker Heidemarie Stefanyshyn-Piper and Steve Bowen will perform the six-and-a-half hour spacewalk. They woke up in the Quest airlock, where they spent the night in a lower air pressure.
That "campout" procedure reduces the amount of time this morning that they need to breathe pure oxygen, which will purge nitrogen from their bodies and prevent decompression sickness while they work in low-pressure spacesuits.
The first of four planned spacewalks is scheduled to start at 1:45 p.m. and last six-and-a-half hours.
You can watch all the action live here at The Flame Trench. Just click on the NASA TV viewer above to launch a viewer.
Stefanyshyn-Piper and Bowen - seen preparing at left along with mission commander Chris Ferguson - will begin their spacewalk by removing an empty nitrogen tank from the station and placing it in the shuttle's payload bay for return to the ground. Then they'll grab a spare part the shuttle brought up, called a Flex Hose Rotary Coupler, that will be stored on a station external platform.
Mission specialist Don Pettit, assisted by Expedition 18 crew member Sandra Magnus, will operate the station's Canadian-made robotic arm to help move the spacewalkers.
Later, around 3:45 p.m., Stefanyshyn-Piper and Bowen will turn their attention to one of the mission's top priorities, the repair of a damaged joint - called a Solar Alpha Rotary Joint, or SARJ - that rotates American solar wings on the station's starboard side.
Over three spacewalks, the astronauts will clean and lubricate the ring that 12 sets of bearing assemblies roll around, allowing the joint to turn the solar arrays like paddle wheels so they can continuously track the sun.
A year ago, NASA discovered increased vibration and power needs to rotate the joint, and a spacewalk later confirmed damage including metal shavings that had collected on the bearings and "pancaked" on the joint's gear ring.
"We don't let it rotate constantly anymore," said Brian Smith, a station flight director, in a NASA interview today.
Today, Stefanyshyn-Piper and Bowen will replace two sets of bearing assemblies.
Meanwhile, inside the station, astronauts will begin unpacking more than seven tons of cargo from the Italian-made Leonardo moving van that they connected to the station Monday.
The gear includes sleep stations, kitchen equipment and a toilet that are needed so the station next year can increase its permanent crew capacity to six, from three.
The astronauts, who are hours ahead of schedule, could begin unpacking a water recycling system that will distill and treat waste water into drinking water, perhaps the most critical function to support larger crews.
"The amount of water that's required to sustain that is very significant, and it's just not possible to constantly be resupplying that the way we are now with the shuttle," said Smith.
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