Shuttle damage discovered

The shuttle Atlantis came back from space last month with a tiny but significant hole in it, apparently from a collision with a piece of space debris, NASA officials said.

The shuttle Atlantis came back from space last month with a tiny but significant hole in it, apparently from a collision with a piece of space debris, NASA officials said. The micrometeoroid did not damage the delicate thermal panels and tiles that protect the shuttle on its return to earth; instead, it struck a radiator panel that extends from the payload bay doors.

By historical standards, it was a major hit, said James Hartsfield, NASA spokesman, who called it 8220;the second-most-damaging particle that we8217;ve encountered in the programme.8221; Hartsfield added, however, that the damage was slight: 8220;It posed no danger to the crew and no change to the mission.8221;

The hole is about a tenth of an inch in diameter at the entry point, with damage extending about an inch around and a half inch deep within the radiator itself, where the particle shattered. On the other side of the radiator, it left an exit hole three-hundredths of an inch in diameter and a crack two-tenths of an inch long.

The radiators are tucked inside the bay when the doors are closed shortly before returning to earth, so the damaged area never faced the searing heat of re-entry. It was superheated plasma entering a hole in the wing of the shuttle Columbia on February 1, 2003, that caused the loss of that craft and its crew of seven.

The obvious high velocity of the impact meant the debris that struck the Atlantis did not come from the shuttle itself since objects floating away from the shuttle have a low velocity relative to the speed of the shuttle.

The tubes in which freon coolant circulates were not punctured; such a problem would have been detected quickly and would have required a hasty return to earth.

Meteoroid debris is one of the biggest risks of space flight, and astronauts inspect the shields at the end of every mission to ensure there is no new damage to them during orbit. If a heat shield had suffered a hit of the same size, Hartsfield said, the damage would have been spotted during inspection.

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Still, Hartsfield said, 8220;Basically, every flight comes back with some type of impact,8221; and so 8220;when you see damage like this, I wouldn8217;t say people are really surprised.8221;

8212;New York Times / JOHN SCHWARTZ