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Stanford Report, March 12, 2003

In wake of shuttle disaster, research on thermal tiles interests NASA

After the crash of the space shuttle Challenger in 1986, NASA approached management science and engineering Professor M. Elisabeth Paté-Cornell to do a risk analysis on some aspect of the space shuttle. Paté-Cornell chose to work not on the O-rings, which had failed on the Challenger, but on the thermal protection tiles.

"It's essential to think beyond the reoccurrence of the past event," says Paté-Cornell. "The reason why I started looking at other parts of the shuttle is precisely that I thought NASA was going to work to death on the cause of the previous disaster, and so let's try to get the next one."

Paté-Cornell received funding from NASA through a cooperative research agreement with Kennedy Space Center. With one of her graduate students, Paul Fischbeck, who is now a professor at Carnegie Mellon University, she did a probabilistic risk analysis for the failure of the space shuttle tiles. NASA received their report in December 1990, and the authors subsequently published three derivative papers, two in 1993 and one in 1994.

Some of Paté-Cornell and Fischbeck's findings -- that some tiles are more important than others and that they can be damaged by falling insulation foam -- have become important in the investigation into the Feb. 1 crash of the shuttle Columbia. When Paté-Cornell gave a presentation to the Columbia Accident Investigation Board in Houston on Feb. 24, the assembled experts showed a lot of interest in this kind of study and the insights it can provide.

Although the cause of the accident is still unknown, damage to the thermal protection tiles at takeoff can't have helped. Says Paté-Cornell, it wasn't a prediction -- it was a risk analysis. "It's the kind of jackpot you hope you never hit."

Jessica Ruvinsky is a science writing intern at the Stanford News Service.