Astronauts make history with first space fix

[Guest Glenn]

Source: AFP,AP

 

HOUSTON, Texas: US astronaut Steve Robinson last night carried out a risky operation to clear two fibres hanging from the Discovery shuttle that could have caused it to overheat when it returns to Earth.

 

Perched on the end of a 17.7m-long robotic arm and carrying a hacksaw and forceps, Dr Robinson became the first astronaut to carry out a spacewalk under the shuttle during its orbit.

 

He pulled out the first ceramic-covered fibre under the nose of Discovery within minutes of starting the operation.

 

"I'm just putting it in my trash bag," he said just after triumphantly holding up the fibre to cameras following the mission.

 

"There's not much to see," he said of the 2.5cm strip that has had teams of NASA engineers agonising for days over Discovery's fate.

 

Dr Robinson, who was accompanied outside the shuttle by Japanese astronaut Soichi Noguchi, then edged towards the second ceramic strip, which also came out with no trouble.

 

"That came out very easily, even less force," he said. "I don't see any more gap filler. I'm doing my own inspection here. It's a very nice orbital belly."

 

Had the fibres resisted, Dr Robinson would have used forceps to pull out the strips. If that did not work he had a makeshift hacksaw ready to cut them off.

 

"You guys did a great job. Congratulations," said the ground controller as Dr Robinson was manoeuvred back.

 

The operation lifted one of the doubts about Discovery's safety as it prepares to return to Earth on Monday.

 

Engineers had feared the tile fillers could upset the stability of the shuttle as it re-enters the atmosphere and cause it to overheat in a similar way to the Columbia disaster on February 1, 2003. Discovery is the first shuttle mission since Columbia disintegrated, killing all seven crew.

 

A crack in the shuttle's thermal shield caused by a piece of foam that hit the wing during liftoff was blamed for the destruction of Columbia.

 

Temperatures on the shuttle skin can reach 1370C during re-entry, and the contour of the vessel's belly has to be smooth to ensure it does not overheat.

 

The shuttle travels at about 26,500km/h into the atmosphere, expanding and contracting in the extreme heat and cold.

 

Dr Robinson had expected to spend about an hour removing or trimming the fillers from the two locations near the shuttle's nose, but it took only a few seconds for him to pull each strip.

 

He admitted the day before leaving it would be a delicate task. And other crew members had expressed misgivings about the repair operation.

 

Before heading to the repair site, the pair spent about two hours installing an external tool and parts platform on the international space station, where Discovery has been docked since Thursday. The platform's installation was the key task of the mission's third spacewalk until NASA officials determined the exposed fillers could threaten Discovery's re-entry.

 

"OK, Andy, I'm in the great outdoors," Dr Robinson told Australian-born astronaut Andy Thomas after he followed Mr Noguchi out of the shuttle's airlock as it passed over Australia.

 

Discovery is now expected to leave the international space station on Saturday and to return to Earth on Monday after its mission was extended by a day.

 

Shards of foam debris came off the external fuel tank during Discovery's liftoff on July 26 and NASA experts have carried out extensive monitoring of the craft's skin to make sure it was not critically damaged.

 

NASA deputy shuttle program manager Wayne Hale admitted yesterday that NASA engineers were analysing a thermal blanket below Discovery's cockpit that appeared to have been hit by debris during liftoff.

 

"I have people who will come back and report within 48 hours, so I will get a status report tomorrow," Mr Hale said, adding that there was some concern the thermal blanket might tear off during re-entry.

 

NASA said the mission management team would convene today to analyse all the data on the blanket and determine if any further course of action -- perhaps an additional space walk -- may be required.

 

President George W. Bush yesterday telephoned the Discovery crew and praised their courage. "I want to thank you for being risk-takers for the sake of exploration," Mr Bush said in a telephone link-up.

 

"Thanks for being such great examples of courage for a lot of our fellow citizens.

 

"As you prepare to come back, a lot of Americans will be praying for a safe return."