Spaceflight Now

NASA, CAIB investigators compare notes on disaster
Posted: April 24, 2003

The NASA Accident Investigation Team today presented results of the agency's on-going analysis of the Columbia disaster to the independent board charged with finding the root cause of the disaster. That presentation is believed to have included one or more possible "best-fit" scenarios based on telemetry, recorded data and debris recovered to date.

One such scenario, which assumes a breach in Columbia's left wing at or near leading edge panel No. 8, was outlined here last weekend. Major elements of that scenario presumably were briefed to the CAIB today. Ten members of the board were either present for the briefing or listening in via telephone. Between 30 and 40 NASA and contractor personnel participated.

But in a short news release, the board said "in order to finalize a primary working scenario, more work is required in four areas of analysis.

"Those four areas are: aerothermal analysis, foam impact testing, testing of flown reinforced carbon carbon panels, and metallurgical analysis from debris," the statement said. "The NAIT provided an overview of the latest data recorder information and the CAIB issued its guidance based on that data and board investigators' continuing analysis of the latest orbiter debris."

The release concluded that "the CAIB has not reached any final conclusions and has not determined the cause of the loss of the shuttle and crew."

A source close to the board said CAIB investigators were in "violent agreement" on the basics of the accident scenario, i.e., a breach in the left wing near RCC panels 8 and 9 led to the disaster. But there is not yet agreement on the finer details of how the plume of super-heated air entering the breach propagated through the wing and ultimately led to its failure.

"It has to do with the level of detail of the (NASA) scenario," the source said. "At a very high level, there's a whole series of facts that I believe we're getting very good agreement on. When you go and penetrate down to detailed timelines, to detailed interpretations, that is where we need to do more work.

"And that's part of what's laid out (in the CAIB press release) in terms of aerothermal analysis, how did the heat that got into the left wing propagate and can you really demonstrate that this sensor going up here is consistent with that or did it come from a different direction? You have to get down to that next level or two of detail. They called it multiple scenarios, I'd say multiple interpretations of the facts."

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