NASA Resisted Concerns, Engineers’ E-Mails Say

A NASA engineer who warned during Columbia’s mission that the shuttle might have suffered debilitating wounds during liftoff said the space agency was treating his safety concerns like “the plague,” internal documents revealed Friday.

The documents, containing a series of e-mail exchanges, show that during Columbia’s final days several NASA engineers continued to raise important -- and prescient -- concerns about whether the Columbia would return to Earth safely.

The disclosures are likely to intensify questions about whether NASA had grossly erred in its assessment of possible damage to Columbia during its launch. The space agency has insisted its reviews were open minded and top officials never disregarded any potential dangers.

NASA also released on Friday a report showing that three pieces of foam insulation, not the single piece previously disclosed, appear to have struck the shuttle 82 seconds after liftoff on Jan. 16 from Cape Canaveral, Fla. The pieces of insulation caused a “shower of debris” to rain down from the shuttle’s external tank.

The new report, one of three analyses conducted by Boeing Co. during the Columbia mission, attempts to gauge the damage to heat resistant tiles from foam debris observed striking the orbiter’s left wing. As with the other two reports, it does not conclusively say that the orbiter sustained catastrophic damage.

In the e-mails, one engineer predicted the insulation might have opened a “gouge” that would allow superheated gas known as plasma to penetrate the shuttle during descent. That’s precisely what happened, investigators now believe.

Another engineer said NASA may have erred in assuming the debris was lightweight foam and raised the prospect that a piece of solid ice could have formed on the external tank and fallen. The impact of a large chunk of ice, the engineer said, would be equivalent to a 500-pound safe hitting the wing at 365 mph.

The engineers complained that they could not get high-level NASA officials to pay attention. One engineer, Robert L. Daugherty, wrote that NASA was unwilling to test their theories and that engineers might have to work on their own time at night to do the tests.

If there was evidence that Columbia’s landing gear was damaged, mission control officials in Houston “would sure as hell want to know whether they should land gear up, try to deploy the gear or go bailout,” Daugherty wrote on Jan. 29. “We can’t imagine why getting information is being treated like the plague.”

Three days after Daugherty wrote that e-mail, Columbia began disintegrating off the coast of California as it reentered the atmosphere, then broke apart altogether over East Texas, killing its seven-member crew.

The e-mails, as well as subsequent investigations, have focused on the tire-well area. If hot plasma did enter the wing, it could have easily caused a tire explosion, said a former senior Boeing engineer involved in the design of the shuttle. Such an explosion would probably blow the tire gear door off and leave little hope of a safe return.

Another NASA engineer, Mark Shuart, suggested that the space agency was being secretive about its investigation into the foam insulation incident. “I am advised that the fact that this incident occurred is not being widely discussed,” he wrote on Jan. 28.

The engineers, who work at NASA’s Langley Research Center in Hampton, Va., could not be reached Friday.

Twelve midlevel NASA engineers took part in this series of e-mail exchanges describing lingering fears about the liftoff accident. NASA has previously released other e-mails, including two from Daugherty, and has conceded that top-level administrators did not see the exchanges until after Columbia was destroyed.

On Friday, NASA officials reiterated their belief that their formal analysis of the liftoff accident -- concluding that Columbia would return safely -- was correct given what they knew at the time.

NASA spokesman John Ira Petty depicted the e-mail exchanges as a group of engineers merely playing “devil’s advocate.”

“These are engineers ... looking at worst-case scenarios,” he said. “They are postulating. That’s what these guys get paid for.”

Even Daugherty wrote in one e-mail that a destructive breach in the shuttle’s shell was “arguably very unlikely.” NASA officials have said that its engineers were unified in their belief that the insulation did not pose a threat to the crew.

NASA officials discovered the liftoff incident while reviewing film of the launch the next day. They asked Boeing, a prime NASA contractor, to assess the possibility of damage, particularly on the ceramic tiles designed to protect the shuttle from high temperatures during reentry.

In a series of reports on Jan. 21, 23 and 24, Boeing engineers weighed the potential for falling foam insulation to damage the heat-resistant tile. The reports generally conclude that the craft would enjoy a “safe return.”

Like NASA, Boeing says it continues to stand by that assessment.

This week, members of the independent panel appointed to investigate the Columbia disaster questioned whether the Boeing engineers had conducted a complete analysis of the potential problems the space shuttle could encounter following the liftoff accident.

If the shuttle was struck by more than one piece of foam debris, as the new Boeing report indicates, it is still not clear how much damage it could have caused to the heat-resistant tiles, experts said.

“This report raises more questions than it answers,” said Paul Fischbeck, a Carnegie Mellon University professor who has studied tile damage on the shuttle for NASA. “They should be able to build a model that answers the question. I don’t think the answer is going to come from finding a missing tile somewhere in Nevada.”

The newest Boeing report also raises questions about what kind of debris could have done the most damage to the orbiter. The common assumption has been that a heavier piece of debris, such as ice, could do more damage than lighter debris such as foam.

But the Boeing report indicates that lighter debris could do more damage, and several experts interviewed Friday agreed.

As any debris falls off the shuttle’s external tank, it slows down because of wind resistance. The speed of the impact depends on how much the debris slows down relative to the accelerating orbiter. Ice would slow down very little as it comes off the tank and therefore might cause less damage than a piece of foam, according to Fischbeck.

The Boeing report addresses these same issues.

It shows that the smallest piece of foam that could have fallen off the external tank would have struck the wing at up to 945 miles per hour and at an angle of less than 10 degrees. By comparison, the largest piece of foam would have hit at up to 700 mph at up to 16 degrees.

What the report does not answer is whether a large piece of foam at slow speed and a high angle causes more damage than a small piece of foam at higher speed and a low angle, according to Fischbeck.

Members of the independent panel also questioned whether Boeing had adequately investigated the possibility that ice could have formed within the insulation on the external tank, weighing it down and causing more damage than NASA had estimated.

NASA declined to address specific questions raised in the e-mails.

Petty, the NASA spokesman, said new tests are underway on the potential damage the insulation might have caused during liftoff. He said damage from the insulation remains just one theory the investigation is focused on.

“We’re going back to look at every conceivable piece of what is a very complex puzzle,” Petty said.

The puzzle that investigators are examining includes the agency’s culture, which was blamed in part for the loss of the shuttle Challenger in 1986.

Then, the Rogers Commission found the agency tolerated poor communication and departmental fiefdoms. The investigation found the managers failed to discuss safety issues and tried to “contain potentially serious problems.”