NASA Worker Says E-Mails Misinterpreted

A NASA engineer who raised provocative questions about potential perils facing the Columbia during the space shuttle’s final flight insisted Monday that his e-mails have been misinterpreted and that he does not consider himself a frustrated whistle-blower.

The comments by Robert H. Daugherty, a senior engineer at NASA’s Langley Research Center in Virginia, shed more light on the much-publicized debate within the space agency over whether Columbia faced possible calamity before its reentry on Feb. 1.

Top NASA officials have been grilled about the debate in Congress, and it is getting close scrutiny from the Columbia Accident Investigation Board.

Daugherty, a pivotal figure in the e-mail exchange, said Monday that his questions about a catastrophic landing-gear failure had been addressed by the time the shuttle was due to return to Earth. But he acknowledged that he felt some lingering concern in the hours before he learned of its demise.

“There was some ambiguity to this whole thing,” Daugherty said, describing his frame of mind as he went to work that Saturday expecting to watch the Columbia land in Florida.

“I had been absorbed in what- if-ing all week, so of course there was some natural uneasiness on my part,” he said. On the other hand, “I certainly believed that everything was going to be perfectly fine.”

Instead, the shuttle blew apart over Texas, killing the seven astronauts aboard.

Engineers at Langley, NASA’s primary center for research on landing-gear systems and aircraft structure, were formally asked by officials at Johnson Space Center in Houston to assess the possibility the shuttle’s landing gear was damaged.

The request came after NASA had determined that several large pieces of foam had broken off the shuttle’s external tank during liftoff, striking the bottom of the left wing near the landing gear door.

Daugherty and a supervisor, Mark J. Shuart, spoke with reporters in a telephone conference call.

While the internal NASA debate over Columbia’s safety has been well aired, Monday’s briefing marked Daugherty and Shuart’s first public statements on the subject since e-mails from them and others were made public last month. Their comments reinforced the view NASA’s top officials have maintained: that the e-mail exchange did not represent an overlooked warning signal and that it was handled through proper channels.

Still, Shuart and Daugherty said that it was a singular debate. Never before had they held such an intense safety discussion about a space shuttle while it was in orbit.

“This was the first time it’s happened that I know of,” he said. Shuart, an engineer who is an authority on the properties of composite materials, is the director for structures and materials at the Langley center, and has worked there for more than 25 years.

Daugherty’s resume is also lengthy. He joined Langley full time in 1981 after stints as an intern and is now a senior researcher in the complex field of aircraft-landing dynamics.

Daugherty, 44, first gained wide public notice three weeks after the Columbia disaster. On Feb. 22, newspapers reported that while Columbia was still in orbit, he had e-mailed his boss lines such as this: “We can’t imagine why getting information is being treated like the plague.”

Referring to analysts who studied the thermal protection system, Daugherty wrote: “Apparently the thermal folks have used words like they think things are ‘survivable’ but ‘marginal.’ ”

In another e-mail released later, Daugherty speculated on what might happen if searing heat penetrated the wheel well and caused tires to explode -- a scenario close to one that investigators are now studying. He also asked a colleague at Johnson Space Center in Houston whether there was any more word on potential thermal system problems -- “or are people just relegated to crossing their fingers and hoping for the best?”

Further, speculating on a scenario in which the Columbia might have to land on its belly without activated landing gear, Daugherty wrote: “I would bail out before I would let a loved one land like that.”

These eye-catching comments, which did not get aired in the top levels of NASA during Columbia’s flight, have forced the space agency to do much explaining in recent days.

NASA Administrator Sean O’Keefe has repeatedly said that he saw no sign the e-mail debate was handled incorrectly. He has pointed out that the e-mails by Daugherty and others are difficult to interpret without knowing the background of the engineers involved and the agency’s extensive safety protocols.

On Monday, backing O’Keefe’s view, Daugherty sought to set his words into context.

For example, he said his “like the plague” comment was not meant as an indictment of the agency as a whole, but rather as an expression of frustration at delay in getting a particular set of data. “All I can say is, it was the way I talk to my engineering buddies,” Daugherty said.

Asked whether he felt his opinions should have received review from higher levels in NASA, Daugherty said: “I don’t think [they] should have. My e-mail was technical issues that I intended to have technical people discuss. That’s exactly what happened.”

Shuart, though, said Daugherty had kept him in the loop. “I can assure you that everything Bob Daugherty was sending was taken seriously by me and those above me,” Shuart said.

Separately, on Monday the investigation board released another revision of the timeline of data that describes the final minutes of Columbia’s flight, indicating that the shuttle may have entered a spin for the last two seconds of its flight.

The timeline shows that the orbiter’s flight control system was unable to counter the aerodynamic forces from the damaged left wing that were attempting to throw the vehicle into a spin. In the last seconds, the ship’s rocket thrusters were firing and the flight control surfaces known as elevons were exerting the maximum effort to maintain control.

Times staff writer Ralph Vartabedian contributed to this report.