Posted on 02/06/2003 1:54:56 PM PST by GeneD
Questions were raised yesterday about whether the foam that came off the shuttle Columbia's external fuel tank was a problem-plagued formulation that several years ago replaced the original insulating foam used on the shuttle fleet.
NASA had sought a replacement because the original foam, called BX-250, contained a chemical, CFC-11, that was to be banned in 2001 because it harmed the ozone layer. The ban on chlorofluorocarbons, or CFC's, was required under an international treaty, the Montreal Protocol, and the Clean Air Act.
Last night, some NASA officials and Republican Congressional staff members said that conservative and business groups were preparing to say that the shuttle disaster was caused by the ban, because the replacement foam was flawed.
But NASA officials said there was no possible relationship, for several reasons. The foam was looking less and less like the cause, they said, and they still use it on the shuttle fleet. They said the piece that broke off and hit the wing of the Columbia was probably the old foam, not the new, more trouble-plagued material.
When it had trouble with the replacement foam, NASA applied to the Environmental Protection Agency for an exemption from the CFC ban, saying "no viable alternative has been identified."
It gained the exemption in 2001, and still uses that foam in a few spots on the shuttle fleet.
Last year, NASA officials said, the agency shifted to a new formulation on most of the external tank, avoiding harm to the ozone layer and the problems experienced with intermediate foam formulas.
Parker Counts, the senior systems manager for the shuttle program at NASA headquarters who previously supervised work on the external tank, said that more than 90 percent of the body of the external tank is now sprayed with the new foam in ways that avoid past problems.
He added that it was "highly probable" in any case that the foam that hit the left wing on this launching was some of the original formula.
Mr. Counts echoed other NASA officials in saying that it seemed clear now that the source of the fatal fault lay elsewhere.
Probably some CYA.
I think we're still looking at this like engineers, and we're being told the engineers' results/conclusions/thoughts as they come.
If you look at it that way, the explanation is pretty straightforward: they've done the analysis, looked at the film (which showed no obvious tile damage), probably done some testing (or have reviewed previous testing), and have not been able to formulate a credible way for a chunk of foam to have resulted in what appears to have been a major breach of the tiles.
That's not to say that the foam couldn't have done it, just that it doesn't seem likely.
NASA itself saying that it had and could cause incredible damage?
Your use of the term "incredible" is not accurate. It can and did cause tile damage. But it was not deep, and (this is important), the previous tile damage never endangered the Shuttle.
Be that as it may, if you look at the accepted list of "don't do this" rules in spacecraft design, they all seem really obvious -- but they were also all learned the hard way. This may be one of those sorts of accidents.
Exactly. How could small pieces be so destructive in prior observations but a huge piece like we saw on the launch video not be destructive? For them to dismiss the foam theory so soon is lokking like CYA of some politically correct environmentalist acts.
Hey, thanks for your answer. One thing I wanted to point out though was it was NASA saying that damage was incredible, not me. That's why I don't understand their backpedaling on it. :-)
So they're questioning it as THE BIG cause.
I'd like to know if it was usual to correct the pull that was occuring with the firing of the small engines. (I know it is an auto feature but have they ever had to do that before?? I guess I'm thinking that they were fired at a "critical time", that they misfired or something like that.
Regardless, they are being very open about it.
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