NASA began opening up two solar arrays on a new 17½-ton addition to the international space station several hours late because of a software glitch early Thursday.
The careful unfurling of the solar wings started with the deployment of a mast on the left side of the new addition.
The software was used to issue commands to a ferris-wheel-like rotating joint which will allow the solar arrays to move with the sun to maximize the amount of power generated. NASA engineers tried issuing commands to the joint overnight but didn’t get the response they wanted.
The glitch put the day’s activities several hours behind schedule. Space shuttle Atlantis’ 11-day schedule is tightly packed, and the arrays need to be deployed in order for astronauts to go on the third and final spacewalk of the mission Friday.
“About the only thing on the timeline that’s accurate at this point is probably the postsleep,” astronaut Kevin Ford in Mission Control in Houston told space station astronaut Jeff Williams, referring to the time after the crew wakes up devoted to personal hygiene.
“Nothing like adding a little drama to the day,” Williams said a short time later.
No stranger to problems
The solar arrays have been mounted on blankets and folded up like an accordion for delivery to space as part of the new $372 million addition added to the space station this week. When fully opened, the two solar arrays, mounted to a common mast, will together span 240 feet.
When the space station is completed in 2010, the solar arrays will provide about a quarter of its power, or more than 32 kilowatts of direct current power.
Two of Atlantis’ astronauts are experienced in deploying solar arrays. Atlantis commander Brent Jett and mission specialist Joe Tanner were members of a crew in 2000 that also delivered a pair of solar wings to the space station. During that mission, the solar panels unexpectedly stuck to each other while they were being deployed, but the problem was fixed.
This time around, NASA has devised a new method for unfurling the solar wings which allows them to be heated up by the sun to prevent any sticking together.