NASA: Spacewalk will have 'higher risk than usual'

— -- Astronaut Scott Parazynski, one of NASA's most experienced spacewalkers, will face grave risks and nerve-wracking challenges Saturday when he is scheduled to fix a damaged solar panel on the International Space Station.

Among the dangers Parazynski could encounter: potential electrical shock, sharp objects that could puncture his spacesuit and a long journey back to the safety of the station.

Then there's the risk of failure. If Parazynski can't fix the panel, the rip could grow, rendering the panel useless. Without the power the panel is supposed to generate, NASA would have to halt further construction on the station, including the addition of laboratories scheduled for December and April.

Parazynski's walk carries "a little bit higher risk than usual," says astronaut David Wolf, chief of NASA's spacewalking branch, but "there comes a time when the station needs repair … where we, with good mitigation and knowledge, accept a higher risk."

As astronauts inside the station issued commands to unfold the panel Sunday, a guide wire snagged. Before the unfurling could be stopped, the panel had two rips, a broken hinge and snarled wires.

NASA engineers, who did not think this could happen, have been working around the clock to stitch together a repair method. The plan calls for Parazynski to ride a jury-rigged work crane out to the damaged section, which is out of sight of his crewmates inside the station.

There he'll try to smooth the wires, either by untangling them or by cutting them. He'll thread metal strips that NASA has nicknamed "the cuff links" through holes in the panel to splint the tears and restore the panel's strength.

Among the difficulties Parazynski, 46, will face:

•Normally, an astronaut on a spacewalk is never more than 30 minutes' travel time away from the door into the space station, in case the spacesuit malfunctions. From his work site on the panel, Parazynski will need to ride the station's robotic arm for as long as an hour to get close to the door.