Glass Beads Found in Shuttle Fuel Line : Aerospace: NASA believes the objects in Parker Hannifin-built device caused a leak that grounded Columbia.

Tiny glass beads that somehow got into a fuel line are believed to have caused a hydrogen leak that grounded the space shuttle Columbia in May, a NASA official said Wednesday.

Workers discovered between 100 and 200 glass beads between one one-thousandth and three one-thousandths of an inch in diameter inside a piece of equipment found leaking on the shuttle, said William Lenoir, associate administrator for space flight.

The beads were found about two weeks ago when the leaky piece of equipment, a so-called “disconnect” assembly used to mate the shuttle to its external fuel tank, was sent to Irvine-based Parker Hannifin Corp., where it was made, Lenoir said.

The beads could have gotten between a shaft in the disconnect assembly and a seal that prevents the hydrogen fuel from leaking, causing the problem, Lenoir said.

Officials are uncertain how the beads could have gotten into the disconnect assembly but were working with the company to find out, he said.

The only clue so far was that the beads were used at the company for other purposes when the disconnect was made in 1986, he said. The beads are used for a variety of manufacturing processes, he said.

“There’s not much question in our minds that that’s implicated” as the cause of the leak in the external tank disconnect shaft seals. “We’ve been unable to find definitively how (the beads) got there,” he said.

The shuttle Columbia, which has been fitted with a new disconnect mechanism, is scheduled to blast off from the Kennedy Space Center in Florida on Sept. 1 for a nine-day astronomy mission that was postponed by the leak in May.

The shuttle Atlantis, grounded by a hydrogen leak in July resulting from an unrelated problem, is currently undergoing repair. That delay postponed a secret military mission.

The groundings came amid a series of setbacks for the space agency that brought a storm of criticism of NASA.