[NASA] Most Difficult and Dangerous Spacewalk Under Way

Should last until 1:00 pm.

Watch it here: http://www.nasa.gov/multimedia/nasatv/index.html



That's the astronaut way out on the end of the arm.






Dangerous spacewalk under way

HOUSTON, Texas (AP) -- Astronauts stepped outside the international space station Saturday morning to fix a ripped solar wing in one of the most difficult and dangerous spacewalking repairs ever attempted.

NASA officials and the astronauts in orbit have worked day and night to plan every detail of the momentous repair mission. The snagged panel must be fixed before space station construction can continue.

"Go out there and fix that thing for us," station commander Peggy Whitson said just before spacewalkers Scott Parazynski and Douglas Wheelock floated out of the hatch.

"We will," Wheelock responded.

The plan calls for perching Parazynski at the end of a 90-foot robotic arm and boom extension for a 45-minute ride to the damage site.

There, he will tinker with what amounts to a damaged electrical generator. The solar panel teems with more than 100 volts of electricity, possibly as much as 160 volts.

To save the solar wing, Parazynski needs to clear whatever snagged the panels and caused the wing to tear in two places while it was being unfurled Tuesday. He will not know what he's up against until he sees the damage up close.

"We've collected a lot of video, a lot of still photography. But nothing's going to be like the moment when Scott Parazynski actually puts his eyes on this area of interest, on this potential guidewire snarl," flight director Derek Hassmann said Friday.

As it is now, the wing poses a structural hazard for the international space station. The damage could worsen and the wing could become unstable, possibly forcing NASA to cut it loose and lose a vital power source for future laboratories.

Once Parazynski has cleared the snag -- possibly by moving the guidewire or cutting it and letting it wind up at the base of the tower -- he plans to install several homemade braces so astronauts can deploy the wing to its full 110 feet. It is about 75 percent deployed now.

Astronauts made the braces from aluminum sheets and insulated tape aboard the linked shuttle-station complex.

Wheelock is nearby to guide Parazynski and the astronauts operating the robotic arm. Italian astronaut Paolo Nespoli is choreographing the outing from inside the station.

This is Parazynski's fourth spacewalk this mission and the seventh of his 15-year astronaut career.

He and Wheelock are wearing partial mittens over their gloves for extra protection. Wheelock pierced the outer layer of a glove near the end of Tuesday's spacewalk, marking the third time in less than a year that a spacewalker tore a glove on something sharp at the space station.

As for the electrical hazards, all of the metal parts on Parazynski's spacesuit have been covered with insulating tape -- triple-taped, in fact -- as have all the tools that he's carrying with him.

"It's not the kind of thing that would burn you, but we could get conduction through the heart, let's say, or mild shocks," said David Wolf, the spacewalk branch chief for the astronaut office.

Copyright 2007 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.

http://www.cnn.com/2007/TECH/space/11/03/spacewalk.ap/index.html