NASA grounds future shuttle flights

Discovery lost foam debris, like Columbia, but no damage reported.

SPACE CENTER, Houston -- NASA grounded future shuttle flights Wednesday because a big chunk of insulating foam flew off Discovery's fuel tank during liftoff -- as it did in Columbia's doomed mission -- but this time apparently missed the spacecraft.

"Until we're ready, we won't go fly again. I don't know when that might be," shuttle program manager Bill Parsons told reporters in a briefing Wednesday evening.

He and other managers do not believe the flying debris that snapped off the external fuel tank harmed Discovery.

"Call it luck or whatever, it didn't harm the orbiter," Parsons said. If the foam had broken away earlier in flight -- when the atmosphere is thicker, increasing the acceleration and likelihood of impact -- it could have caused catastrophic damage to Discovery.

"We think that would have been really bad, so it's not acceptable," said Parsons' deputy, Wayne Hale. He said every indication so far is that Discovery is safe for its return home.

The loss of a chunk of debris, a vexing problem NASA thought had been fixed, represents a tremendous setback to a space program that has spent 2 1/2 years and over $1 billion trying to make the 20-year-old shuttles safe to fly.

The piece of foam flew off Discovery's redesigned tank just two minutes after what initially looked like a perfect liftoff Tuesday morning. But in less than an hour NASA had spotted images of a mysterious object whirling away from the tank.

Mission managers did not realize what the object was -- or how much havoc it would cause to the shuttle program -- until Wednesday after reviewing video and images taken by just a few of the 100-plus cameras in place to watch for such dangers.

Officials do not believe the foam hit the shuttle, but they plan a closer inspection of the spacecraft in the next few days to be sure.

Discovery's astronauts were told of the foam loss before going to sleep Wednesday.

"You have to admit when you're wrong. We were wrong," Parsons said. "We need to do some work here, and so we're telling you right now that the ... foam should not have come off. It came off. We've got to go do something about that."

House Science Committee chairman Sherwood Boehlert, R-N.Y., said NASA is handling the situation "exactly right."

"It doesn't appear that the mission is in jeopardy. Nothing is in jeopardy except the schedule. But I don't want to underestimate the seriousness of it in terms of the future," Boehlert said.

The shuttle is due for retirement in 2010, and a new spacecraft is in the works. President Bush has a lofty plan for NASA to return astronauts to the moon, and eventually to Mars. It's unclear how this latest setback might affect public sentiment for the space program.

Engineers believe the irregularly sized piece of foam was 24 to 33 inches long, 10 to 14 inches wide, and between 2 and 8 inches thick -- only somewhat smaller than the 1.67-pound chunk that smashed into Columbia's left wing during liftoff in 2003.

The plate-sized hole let in superheated gases that caused the shuttle to break up on its return to Earth.

On Discovery, the foam broke away from a different part of the tank than the piece that mortally wounded Columbia. The tank was redesigned for Discovery to reduce the risk of foam insulation falling off, especially big pieces like the one that ended up being shed.

Parsons stressed that the current 12-day mission was a test flight designed to check the safety of future missions. He refused to give up on the spacecraft that was designed in the 1970s.

"We think we can make this vehicle safe for the next flight," he said, declining to judge the long-term impact on the manned space program. "We will determine if it's safe to fly."

Atlantis was supposed to lift off in September, but that mission is now on indefinite hold. Parsons refused to speculate when a shuttle might fly again, but did not rule out the possibility that Discovery's current mission may be the only one for 2005.

He said it was unlikely that Atlantis would be needed for a rescue mission, in the event Discovery could not return safely to Earth and its astronauts had to move into the international space station. Discovery, fortunately, appears to be in good shape for re-entry, he said.

In addition to the big chunk of foam, several smaller pieces broke off, including at least one from an area of the fuel tank that had been modified after Columbia. Thermal tile was also damaged on Discovery's belly; one tile lost a 1 1/2-inch piece right next to the set of doors for the nose landing gear, a particularly vulnerable spot.

Hale said none of the tile damage looked particularly serious, and likely would not require repairs in orbit.

Imagery experts and engineers expect to know by Thursday afternoon whether the gouge left by the missing piece of tile needs a second look. The astronauts have a 100-foot, laser-tipped crane on board that could determine precisely how deep the gouge is.

The tile fragment broke off less than two minutes after liftoff Tuesday and was spotted by a camera mounted on the external fuel tank.

If NASA decides to use its new inspection tool to get a 3-D view of the tile damage -- which most likely will happen -- the astronauts will examine the spot on Friday, a day after docking with the international space station. The inspection of Discovery's wings and nose by the inspection boom on Wednesday turned up nothing alarming, but analysis is ongoing, Hale said.

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