HOUSTON (AP) -- The Columbia accident investigators said Tuesday that the computer model that told engineers a falling chunk of foam hadn't harmed the shuttle's wing at launch was outdated and lacked the right information.
The analytical model had never been used before to predict damage from falling debris during an actual shuttle flight, said former astronaut Sally Ride, one of the board's newest members.
What's more, a team of engineers involved in the study realized they needed more data. They asked NASA officials to seek pictures of the orbiting shuttle, Ride said. The foam from the fuel tank slammed into Columbia's left wing shortly after liftoff, and NASA's video wasn't clear enough.
They needed to know more about the speed and location of where the falling foam hit on the wing.
``If you had given them good information to start with, they could have given you an answer,'' she told reporters, referring to the analytical program used by engineers to assess damage.
``But there wasn't enough information. So you're asking them to predict where something's going to hit but you can't tell them how it started.''
All the unknowns ``led this whole group to say, 'Get us more data, get us some photos.''' Speaking after Tuesday's hearing into the cause of the accident, Ride said the request for photos came out of a meeting that occurred Jan. 21 -- just five days after Columbia was struck by foam.
``It looks as though it was literally a miscommunication,'' Ride said, ``where one group was saying, 'Let's wait until the analysis is complete to see whether we need photos' and then that was interpreted as 'there will be no photos.' In other cases, it was for different reasons. It's a pretty complex story. It's a real web of interpersonal communications.''
Ride said this web apparently stretched even up to the astronauts aboard Columbia, who accepted the engineers' conclusion that they would be in no danger during their descent through the atmosphere on Feb. 1.
That conclusion by Boeing engineers was accepted by virtually everyone, but other company engineers testified earlier Tuesday that the space shuttles' outer thermal protection layers were never meant to be struck by anything other than maybe bugs or rain -- certainly not a 2-pound piece of hardened foam.
NASA came to accept the more than 140 debris strikes that occurred on every flight, and viewed them as essentially a nuisance that called for more maintenance, these engineers told the board. Not all of the impacts were caused by flyaway foam, however.
``I'm not sure that it's an appropriate analogy, but I'd never heard about O-rings before the Challenger accident,'' Ride said. She added that the same thought expressed by the presidential commission that looked into the Challenger disaster, on which she also served, may be echoing again: ``You survived it the first time, so suddenly it becomes more normal.''
The chairman of the Columbia Accident Investigation Board, Harold Gehman Jr., a retired Navy admiral, said neither his panel nor NASA are satisfied with the model that was used in the Boeing analysis during the flight. He described it as a spreadsheet, not a computational model, and noted that it was based on testing of much smaller debris _ not anything nearly as large as what hit Columbia 81 seconds after liftoff.
Investigators suspect the debris caused a breach somewhere along the leading edge of the left wing that allowed scorching atmospheric gases to enter during the spaceship's descent. The shuttle disintegrated over Texas.
So far, about 32 percent of Columbia has been recovered.
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