The Associated Press
CAPE CANAVERAL, Fla. - The biggest, most powerful, most expensive set of solar wings ever built for a spacecraft is about to take flight.
Late tonight, space shuttle Endeavour is due to lift off with the $600 million solar panels, which will provide much-needed electrical power for the international space station.
The pair of glimmering, gold-colored panels will stretch 240 feet from tip to tip and 38 feet across, and cover half an acre, once they are unfurled on the newly occupied space station, Alpha. That's longer than the wingspan of a Boeing 777, longer than even the space station itself.
Attaching and spreading the wings, which are folded like an accordion for launch, make this NASA's toughest construction mission yet. The job falls to five shuttle astronauts who have been training for this flight for more than three years. Two of them will go outside to help install the panels.
The five shuttle crewmen - plus the three men who have been living on Alpha for the past month - expect the unfolding wings to be a breathtaking sight. It will be the largest structure ever deployed in space and will make the station one of the brightest "stars" in the sky.
"I think there's going to be a very sudden shift in people's perception of the international space station, because suddenly it's going to look much, much bigger than it already is," said Canadian astronaut Marc Garneau.
The space station cannot grow without the extra electrical power that the new solar panels will provide. NASA's power-hungry lab module is to be launched in January.
Also, station commander Bill Shepherd and his Russian crew cannot have full run of the place until the new solar wings begin generating electricity. Alpha's skimpy, Russian-built solar panels do not provide enough power to heat the roomy Unity module, which is sealed off, or to run all the station equipment at full blast.
The American-made solar wings - the first of four sets to be launched to the space station - can produce 65 kilowatts at peak power, enough to power about 30 homes on Earth. That is four times the amount of electricity currently generated aboard the station.
The mission is not without danger.
No one really knows how much static electricity will be discharged as the space station zooms around Earth. NASA worries a spacewalking astronaut could be shocked and possibly killed by an electrical arc.
NASA has installed devices on Alpha to neutralize static electricity. If necessary, flight controllers could further reduce the risk by turning the solar panels so they do not face into the direction of travel, but that eats into power.
Three spacewalks are planned during the 11-day mission.
Altogether, the new solar wings and their batteries, radiators and extension beams weigh 35,000 pounds, one of the heaviest shuttle payloads ever. Each wing alone weighs 2,400 pounds and is made of 32,800, 3-inch-square silicone cells and thin Kapton layers.
NASA had to trim as much weight as possible for Endeavour to carry such a massive payload. Among other things, the crew size was limited to five rather than the usual seven.
Engineers even considered removing the shuttle toilet and packing extra plastic bags for the astronauts to relieve themselves. Astronaut Joe Tanner said it was a drastic measure that, thankfully, was discarded.