A NASA flight controller in Houston, who cautioned in an e-mail that a wing of the space shuttle Columbia could burn up on re-entry, says he is now haunted by the warning but was only worrying at the time about a worst-case scenario.
The day after his seemingly prescient e-mail, Jeffrey Kling was the first in mission control to report a sudden loss of data from the shuttle's sensors in the left wing, shortly before Columbia shattered into a fireball on re-entry into Earth's atmosphere the morning of Feb. 1.
Mr. Kling said he wondered to himself afterward: "What did I miss? What did we miss as a team?"
The National Aeronautics and Space Administration allowed a handful of reporters in Houston to meet Mr. Kling after the agency released more than 40 pages of internal memos from him and other engineers.
Several of the memos raised warnings that the shuttle's safety could be breached by damage to the heat tiles.
"When the events started unfolding, there was a little bit of disbelief right at first," Mr. Kling told the reporters.
The Associated Press described Mr. Kling, a mission control officer who oversaw Columbia's landing gear systems, as looking pale and shaken, staring down as he spoke in a hush to the journalists.
The e-mail traffic indicated a broad dialogue between NASA and contractors about the possibility of a fiery shuttle return.
"As far as I know, none of it was shared with the crew at all," Mr. Kling told reporters. "We did not think it was a concern. So we didn't even waste the bandwidth to send them that sort of information. It was just a what-if scenario."
Hashing out possible disaster scenarios is a normal component of the engineering process, former NASA insiders say.
"You routinely go over various contingencies. It doesn't mean you think those contingencies will all become reality," said Brian Thompson, a professor of aerospace engineering at the University of Western Ontario in London, Ont., who worked for NASA after the 1986 Challenger explosion.
"If you look at what the e-mails are saying, there's a lot of people doing their jobs. There's lots of scenarios you play with in your mind because that's what taxpayers pay you for," said former NASA manager Keith Cowing, who runs the Nasawatch.com Web site.
He said he sympathized with Mr. Kling's predicament. "There's no word to express how you feel when your co-workers are killed," Mr. Cowing said.
He said the release of memos is unprecedented, considering NASA's tradition of secrecy.
The head of the agency, Sean O'Keefe, was grilled yesterday about the e-mails when he appeared before lawmakers on the U.S. House science committee.
"Have you fired anyone for not bringing them to your attention sooner?" Representative Anthony Weiner asked Mr. O'Keefe.
Mr. O'Keefe replied that outlining potential disaster scenarios is a normal part of each flight's operations. "We encourage, expect, demand that people exchange ideas and solutions on how to deal with anomalies that occur on flight."