HOUSTON - NASA relied on a flawed analysis of debris damage on Columbia and allowed a web of miscommunication to block a team of engineers from getting photos of the space shuttle in orbit, accident investigators said yesterday.
In some of the sharpest criticism voiced since the investigation board began digging into the cause of the disaster, chairman Harold Gehman Jr. called the computer model used to assess the damage done to the shuttle "rudimentary" and not meant to predict safety.
Former astronaut Sally Ride, the newest board member, said a failed request for military photos "looks as though it was literally a miscommunication."
The analysis led by NASA contractor Boeing Co. during the mission reviewed whether significant damage was done to the left wing by a chunk of hardened foam that came off the fuel tank during liftoff. Its conclusion that little harm was done was a crucial element in NASA's belief that the seven astronauts could return safely.
But the analytical model had never been used before during a shuttle flight, Ride said.
Gehman, a retired Navy admiral, described the model as a spreadsheet, not a computational design, and noted that it was based on testing of much smaller debris - not nearly as large as the 2-pound piece that hit Columbia 81 seconds after liftoff.
Gehman said that although hindsight has revealed the analysis to be wrong, it does not mean the decision-making based on it was wrong at the time.
The engineers relying on the analysis during the Columbia mission realized they needed more data, Ride said. They asked NASA officials to request pictures of the orbiting shuttle, but none were taken.
In the two months since the disaster, attention has focused on flyaway foam insulation as a major suspect in causing the breach in Columbia's left wing. Superheated gases entered the wing, causing the shuttle to break apart over Texas on its way to a Florida landing.
NASA's video of the launch debris striking the wing was not clear enough. The engineers needed to know more about how hard and where the falling foam hit and other details to properly assess the potential damage.
"If you had given them good information to start with, they could have given you an answer," she told reporters. "But there wasn't enough information."
All the unknowns "led this whole group to say, 'Get us more data, get us some photos.'"
Speaking after yesterday's hearing into the cause of the accident, Ride said the request for photos came out of a meeting Jan. 21 - five days after Columbia was struck by foam.
Describing the miscommunication, Ride said it appeared that "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."
Boeing engineers testified earlier yesterday that the space shuttles' outer thermal protection layers were never meant to be struck by anything other than perhaps bugs or rain - certainly not a 2-foot-long piece of hardened foam.
Testimony by engineers and comments by board members seemed to reveal a culture in which problems became acceptable over time because no lives were lost.
In some of the sharpest criticism voiced since the investigation board began digging into the cause of the disaster, chairman Harold Gehman Jr. called the computer model used to assess the damage done to the shuttle "rudimentary" and not meant to predict safety.
Former astronaut Sally Ride, the newest board member, said a failed request for military photos "looks as though it was literally a miscommunication."
The analysis led by NASA contractor Boeing Co. during the mission reviewed whether significant damage was done to the left wing by a chunk of hardened foam that came off the fuel tank during liftoff. Its conclusion that little harm was done was a crucial element in NASA's belief that the seven astronauts could return safely.
But the analytical model had never been used before during a shuttle flight, Ride said.
Gehman, a retired Navy admiral, described the model as a spreadsheet, not a computational design, and noted that it was based on testing of much smaller debris - not nearly as large as the 2-pound piece that hit Columbia 81 seconds after liftoff.
Gehman said that although hindsight has revealed the analysis to be wrong, it does not mean the decision-making based on it was wrong at the time.
The engineers relying on the analysis during the Columbia mission realized they needed more data, Ride said. They asked NASA officials to request pictures of the orbiting shuttle, but none were taken.
In the two months since the disaster, attention has focused on flyaway foam insulation as a major suspect in causing the breach in Columbia's left wing. Superheated gases entered the wing, causing the shuttle to break apart over Texas on its way to a Florida landing.
NASA's video of the launch debris striking the wing was not clear enough. The engineers needed to know more about how hard and where the falling foam hit and other details to properly assess the potential damage.
"If you had given them good information to start with, they could have given you an answer," she told reporters. "But there wasn't enough information."
All the unknowns "led this whole group to say, 'Get us more data, get us some photos.'"
Speaking after yesterday's hearing into the cause of the accident, Ride said the request for photos came out of a meeting Jan. 21 - five days after Columbia was struck by foam.
Describing the miscommunication, Ride said it appeared that "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."
Boeing engineers testified earlier yesterday that the space shuttles' outer thermal protection layers were never meant to be struck by anything other than perhaps bugs or rain - certainly not a 2-foot-long piece of hardened foam.
Testimony by engineers and comments by board members seemed to reveal a culture in which problems became acceptable over time because no lives were lost.
