As NASA tries to eliminate the dangers of falling foam insulation that apparently doomed the shuttle Columbia, independent investigators say they have found problems with four other components that could threaten future missions. These problems, the investigators say, suggest that NASA may be playing down early warning signs on a range of hazards.
Until now, members of the board investigating the accident have warned against concluding that NASA's safety culture has eroded based solely on the circumstances of that accident. Anyone can see danger signals after an accident, Adm. Harold W. Gehman, the head of the board, said at a recent briefing, adding, "OK, well, tell me what the next one is if you're so smart."
The four problems emerged after the National Aeronautics and Space Administration and the Gehman board reviewed thousands of potential shuttle risks. The board also conducted hundreds of interviews, reviewed thousands of documents and ordered new experiments. In its final report to Congress, expected late next month, the board is likely to use this analysis to conclude that NASA's culture is deeply flawed, regardless of what happened on the Columbia mission.
Although NASA devotes enormous resources to finding and fixing problems in the short term, board investigators say, it has not done enough to ensure that the problems will not reoccur, or that other problems do not emerge that might otherwise be foreseeable A member of the board said that taken together, the four problems painted a picture in which "the spacecraft was talking to NASA, and NASA was not listening."
A spokesman for NASA, Robert Mirelson, said on Thursday that "the safety of flight has - from the top down - been a priority" at NASA. He declined to discuss issues under consideration by the board. "All along, we have not commented on comments from the Gehman board until it comes to us as a recommendation," he said.
The problems that worry the Gehman board involve shuttle parts with esoteric names: bolt catchers, hold-down posts, flowliners and "Stoody" balls.
The most striking problem, investigators say, is bolt catchers, which were discussed at a board briefing on Thursday. They are chambers built around the exploding bolts that help the shuttle's solid rocket boosters to break away from the external tank some two minutes after launching. Bolt catchers are supposed to keep the two halves of the 80-pound bolts from striking the orbiter.
But radar monitoring of the Columbia launching showed unexpected debris falling from the shuttle 126 seconds into the flight, suggesting that a catcher might not have caught its bolts.
When the board had them tested, an exploding bolt blew apart the dome designed to retain it. NASA had never tested the actual parts used in flight. "We said, `Let's test it with real flight hardware,' and lo and behold, it didn't meet the safety margins," Maj. Gen. John L. Barry, a member of the board, said in an interview after the briefing. NASA, which performs extensive testing on major systems such as the shuttle's main engine, has done too little to check other parts. With other components, too, the investigators have found that NASA ran simulations and analyzed parts that were like those used in flight, but too rarely conducted full physical testing on shuttle parts that were actually used in flight.
Douglas D. Osheroff, a board member and Nobel laureate in physics, said he was surprised to find that a chart of data on foam characteristics at various temperatures, supplied to him by NASA, was based not on experiments but analysis. NASA had not done the kind of testing on foam that he was able to perform at his kitchen table, he said.
Similarly, NASA never performed the kind of foam testing that the Gehman board is now conducting in San Antonio: Pieces of foam are being shot at leading edge panels taken from the space shuttle Discovery.