Were Environmental Concerns Responsible For The Columbia Disaster?
Thursday, July 28th, 2005With all of the news regarding Discovery’s return to flight, and yet another problem with the insulating foam on the external fuel tank, people are re-examining the Columbia tragedy. Specifically, they are trying to determine why the foam keeps breaking off during shuttle launches.
The Columbia Accident Investigation Board (CAIB) found that the most reasonable explanation for the foam problems was the way the foam was applied to the external fuel tank. They said that there were too many air pockets and other defects, and therefore it was not sticking to the tank like it should.
Subsurface defects were found during the dissection of three bipod foam ramps, suggesting that similar defects were likely present in the left bipod ramp of External Tank 93 used on STS-107.
Source: CAIB Report, page 55, Finding F3.2-6
However, it is another portion of the report which should have raised red flags about the problems with the foam:
Throughout the history of the External Tank, factors unrelated to the insulation process have caused foam chemistry changes (Environmental Protection Agency regulations and material availability, for example). The most recent changes resulted from modifications to governmental regulations of chlorofluorocarbons.
Source: CAIB Report, page 51
In 1997, at the direction of the Clinton Administration, NASA changed the formulation of the foam used to insulate the external fuel tank to eliminate the use of Freon. At the time, Freon was thought to cause many environmental problems. However, their was evidence as soon as the first launch using the new foam that there was a problem:
There was a problem on the first mission where they used the eco-friendly foam. More than one hundred of the tiles were beyond repair, well above the previous average of forty.
The really sad part about all of this is that even though NASA received a waiver which would have allowed them to use the old foam formulation, they chose to stay with the new formulation, even though it had massive adhesion problems. Basically, astronauts’ lives were endangered because NASA made a decision to appear more environmentally friendly rather than to use the best material available for the job.
None of this makes me feel good about the future of NASA. NASA management keeps talking about how they do everything with the safety of the astronauts in mind, but it is hard to believe that when you look at the facts. It seems to me that until they can fix the problem with the new foam, they should return to the use of the old formulation for now. At a minimum, this would reduce the chance of foam separating from the external fuel tank during launch significantly.
Hat Tip: Mike’s Noise
Print This Post
