NASA Engineer Warned of ‘Catastrophic’ Scenarios

A NASA engineer warned two days before the Columbia disintegrated that the space shuttle could be in a “world of hurt” if it was sufficiently damaged by a chunk of foam insulation that struck it during liftoff, copies of the space agency’s internal e-mails revealed Wednesday.

An e-mail outlining “catastrophic” scenarios was written Jan. 30, two weeks after a 2.7-pound piece of foam insulation fell from an external fuel tank and struck the shuttle near its left wing. It was written by Robert H. Daugherty, a veteran project engineer at NASA’s Langley Research Center in Hampton, Va., the nation’s oldest civilian aeronautics laboratory.

Responding to an informal inquiry from NASA officials in Houston, Daugherty surmised that the insulation could have damaged Columbia’s protective heat-resistant tiles or otherwise could have penetrated the craft near its wheel well. If so, the extreme heat encountered during reentry could burst at least one of the tires making up the shuttle’s landing gear, Daugherty contended.

“It seems to me that with that much carnage in the wheel well, something could get screwed up enough to prevent deployment [of landing gear], and then you are in a world of hurt,” Daugherty wrote in the e-mail, which was initially sent to four mid-level NASA officials as part of a broader exchange involving about 12 NASA engineers and analysts. “What might excessive heating do to all kinds of other hardware in the wheel well? ... Do you belly land? ... If a belly landing is unacceptable, ditching/bailout might be next on the list. Not a good day.”

The e-mail made it only to the desks of senior NASA administrators at the Johnson Space Center in Houston after the accident, space agency officials said Wednesday. The shuttle broke apart over Texas as it reentered the lower atmosphere Feb. 1, killing its seven-member crew.

Through a NASA spokesman, Daugherty declined requests for an interview. NASA officials said they were shielding him from the media largely because of the possibility that he might have to testify before an independent panel investigating the Columbia accident.

On Wednesday evening, NASA downplayed the significance of the e-mail exchange, describing it as the informal banter -- even busywork -- typical of the engineers who work at NASA installations around the country.

“We do that all the time,” said Leroy Cain, NASA’s flight director for the mission. “That’s how we train -- we train for the worst case.... I frankly expect my folks to be doing this kind of thing. If you are not thinking about the next thing, you are not doing your job. It’s not just a technique. It’s a mind-set.”

Also, officials pointed out that Daugherty based his argument on the premise that the insulation had caused extensive damage to the shuttle’s tiles or the cover of its wheel well. Senior NASA officials did not agree with that premise at the time -- and, to a degree, still don’t.

Cain, who said he was not aware of the e-mail exchange until earlier this week, added that if Daugherty or other engineers felt that these scenarios were a realistic threat to the crew or the shuttle, they would have called him or another senior NASA administrator. That never happened, he said.

“They are duty-bound to bring that to our attention,” Cain said. “And we are duty-bound to sit down and listen to what they have to say. They didn’t come forward.”

The e-mail exchange raises questions about how confident NASA felt at the time about its conclusion that the foam damage was “insignificant.”

The foam incident occurred Jan. 16, about 80 seconds after liftoff when the shuttle was traveling at 1,900 mph. Engineers noticed it while reviewing launch film the next day.

Concerned, NASA asked officials at the Boeing Co. to assess the potential damage the piece of foam could have had on the shuttle, particularly on the ceramic tiles that protect it from the high temperatures encountered during reentry. Boeing, in partnership with Lockheed Martin Corp., has the prime contract for maintaining and operating the shuttle.

Boeing responded on Jan. 23 that even if the foam insulation had caused “significant tile damage,” it would not imperil the crew. That report was prepared by five analysts in Houston and California. It concluded that the 20-inch-wide piece of foam insulation could have affected a large portion of the left side of the shuttle, particularly its wing and wheel well, and that the chunk would have struck at a velocity of more than 550 feet per second.

Under the worst-case scenario that engineers could devise, the insulation would have damaged a patch of heat-resistant tiles -- but engineers predicted a “safe return.”

The shuttle recorded a series of temperature spikes and sensor failures in and near its left wing in the minutes before it broke apart. One of the sharpest temperature spikes was recorded near the left wheel well, investigators have said. Cain conceded Wednesday that his first thought after mission control lost communication with the shuttle was of the foam insulation accident and the possible damage it might have caused.

However, Boeing and NASA have said they stand by the Jan. 23 analysis, and last week, top NASA officials said the foam insulation incident, although it was the most obvious hitch in the mission -- and one they’re studying again -- was not believed to have led to the shuttle’s destruction. Engineers throughout the space agency, officials said, were also comfortable with the diagnosis.

“Boeing stands behind the work that the engineers did in the foam debris impact study,” company spokesman Dan Beck said Wednesday. “These engineers are some of the best in the world. They did a very thorough, rigorous job.”

Even after the Boeing report, however, some NASA engineers apparently still felt that more analysis could be done on whether the insulation could have directly hit the shuttle’s wheel well, where its landing gear is stored during the mission, officials said Wednesday.

On Jan. 27, four days after receiving the Boeing report, NASA officials informally called engineers at Langley Research Center for further analysis of the potential impact of the insulation on the shuttle’s tires. NASA had called Langley for advice about tire safety in the past, said Langley spokesman Keith Henry, but never during a mission.

Daugherty wrote his e-mail in response to NASA’s calls to Langley, officials said Wednesday. In the e-mail, Daugherty was quick to point out that he was “erring way on the side of absolute worst-case scenarios.”

“I don’t really believe things are as bad as I’m getting ready to make them out,” he wrote. “Admittedly, this is over the top in many ways, but this is a pretty bad time to get surprised and have to make decisions in the last 20 minutes” of flight.

Daugherty got a response the next day from David F. Lechner, a NASA official in Houston who works on the agency’s mechanical, maintenance, arm and crew systems team. No one outside the team received a copy of the e-mail exchange until after the accident, officials said Wednesday.

“I really appreciate your candid remarks,” Lechner wrote on Jan. 31. “Like everyone, we hope that the debris impact analysis is correct and all this discussion is moot.”

Other e-mails and calls were part of the discussion, but they were unavailable Wednesday.

Daugherty also suggested that NASA conduct tests at its Ames Research Center in Mountain View, Calif., on whether the shuttle could land with its landing gear down but with “two flat tires.” NASA said Wednesday that it was not sure whether the tests were done.

Daugherty has performed extensive analysis for NASA since the 1980s.

In 1995, for instance, he partnered with the Michelin Aircraft Tire Corp. in Charlotte, N.C., to analyze the durability of radial tires designed for jumbo jetliners and, potentially, for the eventual development of new, supersonic transportation. In 1997, he examined a modification of the space shuttle’s runway at Kennedy Space Center in Florida.

Cain said that if NASA had been able to confirm damage to the shuttle’s landing gear or tires, it would have considered either a belly landing or asking its crew to bail out of the craft.

Bailing out, however, would not have been an option in this case. Astronauts wear parachutes as part of their standard uniforms during reentry, said NASA spokesman James Hartsfield. If they have to bail out, they are instructed to slide down a pole that ensures they are clear of the wing before they let go.

However, Hartsfield said astronauts can bail out only if the craft is flying at an altitude below 50,000 feet. Columbia never made it below 200,000 feet.

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Times staff writer Peter Pae contributed to this report.