E-mail warned of descent disaster risk
JOHNSON SPACE CENTER, Texas (CNN) -- An e-mail passed between NASA engineers two days before the fatal breakup of the space shuttle Columbia discussed worst-case scenarios involving tiles on the orbiter's underbelly that may have been damaged shortly after liftoff, specifically dealing with failures during descent.
Robert Daugherty, an engineer, outlined several scenarios in his e-mail to David Lechner, who worked with the shuttle's mechanical systems. They were based on possible outcomes of tile damage the orbiter may have suffered only 80 seconds after it lifted off from Kennedy Space Center January 16.
When they analyzed video of the liftoff a day later, NASA officials noticed what they believe was a piece of foam breaking off the external tank and glancing off the underside of the shuttle's left wing.
"I am admittedly erring way on the side of absolute worst-case scenarios and I don't really believe things are as bad as I'm getting ready to make them out," Daugherty wrote in his January 30 e-mail. "But I certainly believe that to not be ready for a gut-wrenching decision after seeing instrumentation in the wheel well not be there after entry is irresponsible."
As the shuttle streaked across the sky February 1 toward its landing site in Florida, controllers at Johnson Space Center in Houston remarked that sensors inside the wheel well showed higher temperature readings. Other sensors were shutting down, one by one.
Minutes later, the shuttle broke up, killing all seven crew members.
In his e-mail, Daugherty theorized that the shuttle's landing gear may not deploy if there was "a substantial breach of the wheel well."
"It seems to me that with that much carnage in the wheel well, something could get screwed up enough to prevent deployment and then you are in a world of hurt," his missive said.
NASA Administrator Sean O'Keefe, testifying before a joint committee of Congress earlier Wednesday, said that nothing during the mission hinted at the impending disaster.
"During the 16-day STS-107 mission, we had no indication that would suggest a compromise in flight safety," he told lawmakers. (Full story)
In his e-mail, Daugherty ran through several horrific scenarios, including having the landing gear door blow off its hinges, having only part of the landing gear functioning for touchdown, or trying to land the shuttle on its belly.
"If belly landing is unacceptable, ditching/bailout might be next on the list. Not a good day," he wrote.
CNN Space Correspondent Miles O'Brien pointed out that communications such as this are common between engineers, whose jobs involve developing such scenarios and solutions.
The shuttle team ultimately decided that any possible damage from the foam was not serious.
Meanwhile, the Columbia Accident Investigation Board arrived at Kennedy Space Center Wednesday to look at the debris that has been trucked there from collection fields in eastern Texas and western Louisiana. (Full story)
The pieces will be laid out in a large hangar on a huge grid taped to the floor -- a grid in the shape of the Columbia. Investigators are trying to place the debris on the grid site where it would have been on the orbiter.
O'Keefe had asked the board to render a conclusion in 60 days, if it can, as to what exactly brought the shuttle down. The board has indicated it may ask for more time.