Astronauts today were preparing for a spacewalk to finish rewiring the International Space Station's power grid, while NASA, stymied in its efforts to free a jammed solar panel, considered turning to the spacewalkers for help.
Lead spacewalker Robert Curbeam will team with first-timer Sunita Williams to complete a power grid rewiring that Curbeam and Christer Fuglesang, Sweden's first astronaut, started on Thursday.
The rewiring, delayed after the 2003 Columbia disaster, will provide a power upgrade needed to support additional laboratories due to arrive next year.
NASA said the six-hour spacewalk could be extended by up to one hour to inspect, and possibly help resolve, the problem with the panel.
"We are currently visualizing this as an inspection task," Stephen Robinson at Mission Control told the astronauts on Thursday. "Think of it as going up and taking a good close look and telling us what is really going on."
The 110-foot (33-metre) panel retracted enough on Wednesday to allow new solar arrays to rotate and track the sun. But NASA needs the whole span folded up so it can be moved to a new position next year.
NASA had concerns the panel would not retract as planned because it had been exposed to the extreme temperatures of space for six years - twice as long as planned - after Columbia halted construction on the station until this year.
Kirk Shireman, deputy space station program manager, said the astronauts could be asked on Saturday to push on the storage box to try to free a guide wire they suspect is preventing the array from folding properly.