Astronauts begin spacewalk to rewire station

HOUSTON, Dec 16: A veteran spacewalker and his rookie partner slipped outside the International Space Station today to complete a power rewiring job that should leave the outpost ready for the long-delayed addition of European and Japanese laboratories.

''Bye-bye Bob,'' sang out first-time spacewalker Suni Williams as she watched astronaut Robert Curbeam float through the airlock into open space. She followed a few minutes later.

''Welcome to the club, Suni,'' Curbeam said.

The spacewalk, which began at 2:25 p.m. EST (0045 hrs IST) was to be the third and final outing of space shuttle Discovery's 12-day flight. NASA managers, however, were toying with the idea of a fourth spacewalk to fix a jammed solar wing panel that had to be folded up to make room for the station's new wings to rotate.

After dozens of attempts to automatically fold up the 110-foot (33-metre)-long panel, flight directors gave up with the wing still about half-way out. The panel must be completely folded into a storage box so it can be relocated to another part of the station next year.

Managers have asked Curbeam, who was on his sixth spacewalk, and Williams to look at the panel's guide wires if they can finish their primary jobs early. They also may push gently on the panel's metal storage box to try to clear whatever is preventing it from smoothly folding up and tucking inside the container.

WAIT UNTIL MARCH

? If that fails, NASA could send Discovery's spacewalkers on a fourth outing on Monday to free the solar wing. Managers also were considering having the space station crew tackle the job during a spacewalk after Discovery departs, or waiting for the next shuttle crew, due to arrive in March, to fix the problem.

In preparation for the power upgrade, flight controllers turned off half the space station's electricity to make sure the spacewalkers would not handle any live lines as they disconnected and reattached cables to hook up the new power grid. The work mirrors what Curbeam and astronaut Christer Fuglesang completed on their second spacewalk on Thursday.

Flight directors have their fingers crossed the second set of switches, circuits and a critical cooling pump works just as well.

The spacewalkers also plan to move packages of debris shields from a stowage platform in Discovery's cargo bay onto a temporary fixture on the station. The shields, intend to lessen the impact of any micrometeoroid impacts, will be installed on the Russian service module during a spacewalk next summer.

If NASA dispatches Discovery's astronauts on a fourth spacewalk to fix the jammed panel, the shuttle's departure from the station would be delayed until Tuesday. The work also could force the astronauts to skip a final inspection of the shuttle's heat shield before Discovery plunges through the atmosphere on Thursday for landing.

NASA has been meticulous about scouting for damage on the shuttle's protective heat shields since losing Columbia to a debris strike in 2003.

Managers have no concerns that Discovery's heat shield sustained Columbia-like damage during launch, but like to make a final check before the shuttle leaves orbit to make sure the ship wasn't hit by a micrometeoroid or piece of space debris.

The shuttle does not have enough supplies to stay in space beyond December 23 and NASA reserves two days for weather-related landing delays. Touchdown is planned for Dec. 21 at the Kennedy Space Center in Florida.

REUTERS