Discovery astronauts rewire part of space station (AFP)
15.12.2006 03:49 Space - Source: Yahoo space
Mission specialist Robert Curbeam and Christer Fuglesang, Sweden's first astronaut, remained outside the ISS exactly five hours rewiring the orbiting space lab for a new solar array that will double its power output.
The astronauts managed to work quickly, completing their assigned tasks an hour ahead of the scheduled time, NASA said.
"We are at the end of the EVA (extra vehicular activity). We really have enjoyed the day and we have nothing extra for you guys so you can go right to the airlock," a mission control specialist in Houston told the two astronauts.
The delicate and potentially risky work involved shutting off the electricity to half the space station to prevent the astronauts from getting electrocuted.
However, the ISS remained fully powered as the electricity from the functioning side was rerouted to the other, inactive half.
A third spacewalk is scheduled for Saturday, when Curbeam and mission specialist Sunita Williams will complete the rewiring job and install a camera on the ISS to allow for future construction work on the space station.
Three spacewalks were initially scheduled for the Discovery mission, but NASA has not ruled out a fourth to fully retract a six-year-old solar array on the ISS that got stuck half-way on Wednesday as it was being activated by remote control from inside the ISS.
The array was being folded like an accordion to allow the sun-tracking rotation of a new solar array that was installed during an Atlantis mission in September.
Although the mechanism jammed, NASA deemed the old array sufficiently retracted to deploy the new solar array, which will generate twice the electric power of the older one.
It was unclear whether the 12-day Discovery mission would be extended in case a fourth spacewalk is needed to retract the old array manually and reposition it elsewhere on the space station.
The work Curbeam and Fuglesang completed Thursday has also prepared the ISS for two additional solar arrays to be installed in the future. When completed, the ISS will have four solar arrays providing it with electricity.
Construction on the space station resumed in September with the Atlantis mission, after a three-year hiatus following the 2003 Columbia disaster.
The Discovery mission is part of 14 shuttle flights NASA has planned over the next four years to finish the ISS by 2010, when the shuttle fleet, down to three vehicles, is to be retired.
Discovery blasted off late Saturday from Cape Canaveral, Florida -- the first nighttime liftoff in four years. It docked on the station Monday and is to remain there eight days. The shuttle is due to return to Earth on December 21.
National Aeronautics and Space Administration engineers said two preliminary inspections carried out after takeoff and shortly before Discovery docked with the ISS found no damage to the Discovery's heat shield during launch.
Such inspections on the shuttles have become routine since the Columbia tragedy.
Columbia's heat shield was pierced by foam insulation that peeled off its fuel tank during liftoff, causing the shuttle to disintegrate during its return to Earth in February 1, 2003, killing all seven astronauts on board.
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