Shuttle spacewalker set for risky repair work

DISCOVERY astronauts are today set to perform a high-stakes task that has never before been attempted: sending a spacewalker beneath the craft to repair material sticking out from the ship’s thermal tile belly.

NASA says the protruding material could cause dangerous overheating during re-entry and lead to another Columbia-type disaster.

The agency will put astronaut Stephen Robinson on the space station’s 18-metre robotic arm as part of an unrehearsed manoeuvre.

The arm will be operated by astronauts inside the station, who will bend and manoeuvre the arm carrying Mr Robinson so he can reach the shuttle’s belly.

Once there, he’ll tug out the ceramic fabric filler with his gloved hands. If that doesn’t work, he’ll use a makeshift saw to cut away the material, which is sticking out about an inch from two spots near Discovery’s nose.

“I am pretty comfortable with using tools very carefully,” Mr Robinson said early yesterday during a crew press conference from aboard the space station. “But no doubt about it, this is going to be a very delicate task. But as I say, a simple one.”

Mr Robinson said the makeshift saw will only be used if other methods to remove the gap fillers are unsuccessful.

Later yesterday, US President George W Bush got a direct line to the Discovery.

He thanked the crew for their work and wished them safety in their mission.

“I just wanted to tell you all how proud the American people are of our astronauts,” he said. “I want to thank you for being risk-takers for the sake of exploration. Thanks for being such great examples of courage for a lot of our fellow citizens.”

Deputy shuttle program manager Wayne Hale says if none of the proposed methods work, there will likely be some head scratching for a day. However, he says the agency will find another method and try the repair again tomorrow or Friday.

Engineers simply don’t know enough about potential problems that could be caused by the protruding gap fillers, some of which protect tiles from hitting one another during launch.

“When we first heard about it, I think a number of us did have misgivings,” astronaut Andrew Thomas said. “We were concerned about it. We were concerned about the implications of it.”

But after a careful review of information sent from the ground, Mr Thomas said he believes the repairs are justified given “every indication is that the removal of the material should be pretty straightforward and pretty easy”.

Mr Hale said the decision to attempt the repairs in orbit was simple and a way “to set our minds at rest.”

Discovery commander Eileen Collins told mission control early yesterday that her crew would reschedule its joint meal with the space station’s crew and instead focus on procedures for the mission’s third spacewalk, expected to take seven hours.

Discovery will remain docked at the station until Saturday. The shuttle is set to return to Earth on Monday.