Safety Worries Ground Shuttles

With Discovery’s crew about 200 miles above Earth, NASA on Wednesday abruptly suspended all scheduled shuttle flights after determining that a piece of insulating foam -- nearly as large as the piece that doomed Columbia in 2003 -- had peeled off the craft’s external fuel tank during launch.

The space agency said there was no evidence that Discovery was hit or damaged by the debris.

But the loss of insulating foam after two years of study and $1.4 billion in upgrades to the shuttle was a blow both unexpected and disappointing.

“We have to take a step back,” Bill Parsons, shuttle program manager, said during a news briefing at the Johnson Space Center. “Until we’re ready, we won’t go fly again.”

The next scheduled launch was to be Atlantis, which could have come as early as September.

NASA left open the possibility of launching Atlantis to rescue Discovery’s seven-member crew at the International Space Station if the shuttle sustained serious damage and could not return to Earth. Atlantis was being readied, but NASA said any quick launch was remote.

The soonest Atlantis could be launched, if it were needed, would be 25 to 30 days, Parsons said in an interview on ABC’s “Nightline.”

If any damage were found on Discovery, the only other solution would be to try to repair it in flight.

The astronauts’ mission calls for a spacewalk to test two repair techniques, one for the heat-resistant tiles that cover most of the orbiter, and the other for damage to the reinforced carbon panels covering the leading edges of the wings and the nose cone. Both use a goo-like solution that would be slathered over the torn surface.

A third repair technique -- which the crew had not planned on testing but had the tools and supplies to carry out -- would call for inserting a spindle with a flat metal cover into a hole on the carbon panels. The metal cover would act as an umbrella over any damaged area.

The astronauts have said they would be reluctant to entrust their lives to unproved technologies.

Charles Camarda, a mission specialist and engineer on Discovery, said weeks before the launch that even small changes made to the orbiter’s surface could alter the craft’s aerodynamics, throwing the orbiter out of control when it reentered Earth’s atmosphere.

At that time, the crew agreed that it would prefer to wait at the space station to be rescued.

The space station carries enough food to last its two onboard astronauts and the seven newcomers about 43 days.

NASA officials said it was too early to speculate about damage to Discovery.

“The good news is, the orbiter appears to be in good shape,” N. Wayne Hale Jr., the shuttle’s deputy program manager, said at the news briefing.

Parsons would not say the foam did not hit the orbiter. But Hale pointed to video images that appeared to show the foam drifting away from the orbiter, not toward it, at the time when the solid rocket boosters separated from the shuttle.

NASA engineers are continuing to download images of the launch and expect that they will be able to say more definitively by today whether the chunk of foam hit the orbiter, and where.

The foam that came off was from the Protuberance Air Load ramp, or PAL, located above the liquid oxygen feed line on the external fuel tank.

The ramp provides protection against the supersonic forces the shuttle is subjected to as it drives against gravity from zero to 17,500 miles an hour in the first 8.5 minutes after launch.

“We cannot [launch] with PAL ramps coming off,” Parsons said.

“We have to go fix this.”

The foam was estimated to be 33 inches long and 8 inches wide. The piece of foam that hit the leading edge of the left wing on the space shuttle Columbia as it lifted off in January 2003 was estimated at 27 inches long and 18 inches wide.

Columbia was hit 82 seconds after liftoff. The chunk floated away from Discovery two minutes into the flight, when the solid rocket boosters separated from the shuttle.

At the time of the Columbia accident, most NASA officials believed that foam, which is applied to the super-cooled external tank to keep ice from forming on the outside, could not harm the orbiter.

Top NASA managers were so confident that they refused requests by lower-ranking engineers to ask the Defense Department to use its satellites to photograph the damage.

The foam tore a hole in the wing. When Columbia attempted to land on Feb. 1, 2003, air heated to 5,000 degrees Fahrenheit rushed into the cavity and tore the orbiter apart, killing all seven astronauts.

“We’re treating it very seriously,” Hale said Wednesday of the new finding. “Are we losing sleep over it? Not yet.”

Meanwhile, Discovery astronauts completed their second day in space, using remote equipment to scan the hull for damage and preparing for today’s scheduled docking at the space station. One purpose of the mission is to take supplies to the station.

The crew is scheduled to perform a back-flip maneuver while docking with the space station so that the station’s astronauts can take pictures of the underside of the orbiter as it approaches.

NASA said the crew also would perform a scanning maneuver Friday of the underside of the orbiter, using a boom with a camera and laser equipment installed just for that purpose.

They will be looking at several places where bits of tile broke off.

Although a gouge that was deep enough could be hazardous to the orbiter, officials said they did not think the thermal protection system had been compromised.

Nonetheless, engineers were building a mock-up of the nose landing-gear area and planned to test it in searing heat before deciding whether the dings would need to be repaired.

The crew had been informed of the foam problem, Hale said.

One leading member of the panel that investigated the Columbia accident, Stanford University physics professor Douglas Osheroff, said Wednesday that it was “quite remarkable that on the very first flight” after Columbia that “they could have a serious problem.”

The external fuel tank is covered with 1,200 square meters of foam. The Columbia Accident Investigation Board recommended eliminating foam to the greatest possible extent. Although it did extensive research, NASA was unable to resolve the problem of foam shedding during launch.

Osheroff said he visited the Lockheed-Martin plant where the external fuel tanks for the shuttle were made. Managers there told him the problem wasn’t the foam, but the weakness of the thermal protection system.

Also during the board’s investigation, scientists around the country offered proposals to improve the quality of the foam. One proposal came from USC’s Composite Center.

None of the proposals was adopted by NASA.

Engineers eliminated the foam that was the source of the piece that fell off and hit Columbia’s wing. And they believed other changes had made it unlikely that any more large foam chunks would fall off.

“Our expectations were we wouldn’t have an unexpected debris event,” Parsons said. “We were wrong.”

During the “Nightline” interview, Parsons appeared to take a stronger position on astronaut safety, saying “absolutely not” when asked if the members of Discovery’s crew were in danger.

“I just have to say we missed something,” he said. “And we were very lucky that it didn’t impact the orbiter.”

Asked if the problem could have led to a Columbia-style accident, Parsons said: “I can’t say it couldn’t. This was a big piece of foam.”

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Johnson reported from Houston and Vartabedian from Los Angeles.