HOUSTON, Nov 3 (Reuters) Two astronauts floated out of the International Space Station today on a risky spacewalk for what could be a make-or-break repair for completion of the 100 billion dollars space outpost.
Scott Parazynski was headed out to the farthest reaches ofthe station to mend a solar power panel that is torn, butproducing about 100 volts of power and and if touched could give a powerful shock.
''Go out and fix that thing for us,'' station commander Peggy Whitson said as the men left the station more than 320 km above the Earth.
''We will,'' one of the spacewalkers responded.
The torn, wing-shaped panel is partially extended and needs to be unfurled to its full 110-foot (34-metre) length to workproperly.
In the panel's current condition, NASA said it does not want to move ahead with expansion plans that call for finishing the outpost by 2010 when the space shuttle fleet needed for construction is to be retired.
Europe's Columbus laboratory is set for delivery by space shuttle Atlantis in December, five years behind schedule, followed by Japan's three-part Kibo complex next year.
To get to the damaged wing, Parazynski had to strap himself to an arm about 75 feet (23 metres) long that combines an extension boom from the docked space shuttle Discovery and the station's robot arm.
Spacewalk partner Douglas Wheelock was to stay on the station structure, helping guide robot arm operators Daniel Tani and Stephanie Wilson as they gingerly steered Parazynski on a 45-minute ride into place.
INSULATING TAPE To minimize the danger of shock, all of Parazynski's tools and the metal surfaces on his spacesuit have been wrapped in insulating tape. As he works, Wheelock will watch and warn him if his tools and tethers get too close to the solar panel.
Plans for the seven-hour spacewalk call for him to thread six home-made, cufflink-like straps through holes in the solar array so that it can be fully stretched out without further ripping.
The solar panel tore in two places, one of them almost three feet (one metre) long, when a guidewire snagged as it was being unfurled on Tuesday. The panel extended about 90 feet (27 metres) before the damage was spotted.
Astronauts on the space station said they could not see the ripping because the sun was in their eyes.
The solar panel repair took precedence over another critical power problem that NASA also will have to fix later to have full power for the station, which is a project of 15 nations.
On Sunday, NASA had to lock in place a giant circular joint that rotated solar panels on the other side of the station after spacewalker Tani found metal shavings inside indicating moving parts were grinding.
The 10-foot (three-metre) joint keeps the solar arrays pointed at the sun to maximize electricity production.
NASA had to scramble to put together Parazynski's spacewalk plan and said if it does not work, another spacewalk could be required before Discovery leaves the station.
The shuttle launched from Florida on October 23 and is scheduled return to Earth on Wednesday.
REUTERS SKB KN1617