Astronauts begin daring spacewalk to repair damaged panel

Two astronauts from the shuttle Discovery began a daring spacewalk yesterday to repair a torn solar wing deemed vital for the future of the International Space Station.
The US space agency said fixing the ripped solar array has become the top priority for the Discovery shuttle mission because without it there was a risk the tear could spread and render the power-generating wing useless.
Astronauts Scott Parazynski and Doug Wheelock emerged into open space shortly after 6:00am (1000 GMT), the National Aeronautics and Space Administration (Nasa) said.
Parazynski, 46, an experienced spacewalker, is carrying out most of the unprecedented and dangerous repair job.
After making his way across the station's truss structure, he attached himself to a 15-meter (49 feet) extension boom attached to the space station's 18-meter (59 feet) robotic arm and began a ride to the damaged panel.
Attached to the boom by his feet, the astronaut will try to loosen the snagged wire that caused the tears on the two solar panels without touching the array which carries some 300 volts, according to Nasa.
"If he can clear that snag without actually cutting the cable or the guide wire, I expect it to be a quick fix," ISS flight director Derek Hassmann told reporters on Friday.
Then Parazynski will try to sew the wing back together by inserting tabs or "cuff links" through the holes in the array, which Nasa hopes will allow it to be fully extended without further damage.
"I would expect if he does not have to do any cutting... I think we'll be done in 30 minutes at the work-site," Hassman said.
"And even then I expect that two hours and 30 minutes at the work-site will be plenty of time to do what we need to do."
Nasa says the solar array, one of three on the space station, is critical to providing extra electricity for planned European and Japanese science labs.
The European Columbus laboratory is due to be delivered to the ISS in December and the Japanese Kibo lab in April 2008.
Wheelock will accompany Parazynski from the station's truss while mission specialist Stephanie Wilson aboard the shuttle and engineer Dan Tani on the ISS will maneuver the robotic arm.
Italian mission specialist Paolo Nespoli will serve as the coordinator for the spacewalk.
Parazynski will have to avoid touching the electrified solar panels and rely entirely on tools that were rounded up on the shuttle.