US: A spacewalking astronaut gently pulled two potentially dangerous strips of protruding filler from Discovery's tile belly with his gloved hand yesterday, successfully completing an unprecedented emergency repair.
Astronaut Stephen Robinson said both pieces came out easily during the six-hour spacewalk. He did not have to use a hacksaw put together in orbit that he brought along just in case.
"That came out very easily, probably even less force," Robinson said of the second piece. "I don't see any more gap filler. I'm doing my own inspection here. It is a very nice orbital belly."
NASA officials had determined that the exposed ceramic-fibre fillers could lead to overheating and a possible repeat of Columbia's disastrous re-entry.
Robinson attached a special foot restraint to the international space station's 17m (58ft) robotic arm and fellow astronauts manoeuvred the arm so he could reach the shuttle's belly. They were careful his helmet and feet did not contact the fragile ship. It was the first time an astronaut has ventured beneath a shuttle.
Robinson took only the essential tools for the repair - leaving a tile-repair kit just outside the airlock. He also secured his safety tethers between his legs and behind him to avoid accidentally striking the vehicle.
Once under Discovery's belly, Robinson expected to spend about an hour removing or trimming the fillers from two locations near the shuttle's nose. But it took mere seconds for him to pull each strip.
His spacewalking partner, Soichi Noguchi of Japan, watched 22m away, from a perch on the space station. "Steve, we trained for four years; you're going to spend the next four years signing autographs," Noguchi told Robinson once the repairs were done.
Those who watched from space and the ground were fascinated by the never-before-seen views.
"Steve, could you move your hand out of the field of view," astronaut Andrew Thomas radioed Robinson, who had a camera attached to his helmet. "We were enjoying the view as much as you were."
Nasa thought the first gap filler the trickier. They believed it remained glued to a shim that was bonded to a thermal tile.
There are 24,300 glass-coated tiles on the shuttle, most on its belly. The tiles protect the shuttle from extreme temperatures in orbit and insulate the ship during launch and re-entry.
The filler material protects the tiles from bumping against one another during launch, but isn't needed for landing because of the difference in the airflow.
Once the work was done, Thomas requested the spacewalkers to return to the shuttle. He said it had been a long day.
Discovery, set to land on Monday, is the first shuttle to return to orbit since the Columbia tragedy. - (AP)