WASHINGTON, D.C.--"In four simple words: The foam did it." That was the pithy explanation of the shuttle tragedy, described at a press conference today by G. Scott Hubbard, director of NASA's Ames Research Center and member of the Columbia Accident Investigation Board (CAIB). But as members of CAIB presented their final report on the causes of the Columbia accident, they made it clear that attitudes and conflicting pressures within NASA contributed to the disaster.
Foam has long been a leading suspect. A little more than a minute after launch, a doormat-sized piece of insulating foam fell from a structure that connects the shuttle with its external fuel tank. Based upon images from the flight, computer simulations, and foam impact tests, the board concluded that the errant insulation damaged Columbia's heat shielding on the leading edge of the left wing. Upon reentry, superhot gas sprayed through the breach in the shielding, weakening the shuttle wing's aluminum skeleton. As the damage to the left wing worsened, the shuttle's computers couldn't prevent the Columbia from yawing out of control. The spacecraft then broke up over Texas, killing all seven astronauts on board. This is "a self-consistent picture that we have a very high degree of confidence in," said board member Sheila Widnall, a professor at the Massachusetts Institute of Technology.
Board member and Air Force General James Barry argued that a "broken safety culture" at NASA also had a role in the disaster. As the report describes, safety was compromised because of managerial concerns such as keeping to a set launch schedule. The pressure to reach a key milestone for the assembly of the international space station conflicted with NASA's need to keep the shuttle safe. Furthermore, the safety program complacency bears an uncanny resemblance to the attitude toward problems with the shuttle fleet before the loss of the Challenger in 1985.
As a result, CAIB recommends that NASA create an office responsible for all technical aspects of the shuttle, including launch readiness and hazard analysis, that is insulated from the pressures of schedules, mission goals, and budget problems. In other words, NASA should establish an office that "would have direct authority for safety, reliability, and quality assurance throughout the agency. The office ... should be independent of other NASA functional and program responsibilities." Unfortunately, those other words come from the 1986 Report of the Presidential Commission on the Space Shuttle Challenger Accident. The wording in the CAIB report is slightly different, but the message is depressingly the same.
The CAIB report