"Gil" wrote in
oups.com:

This one is a NASA link after STS-87. Looks less and less like an urban
legend to me.

http://quest.arc.nasa.gov/people/jou...s87-12-23.html

That depends on what issue you're talking about.

It is a fact that NASA changed the blowing agent for the mechanically-
applied acreage foam in 1997, and that this resulted in an increase in
orbiter TPS damage due to "popcorning" in the shuttle flights for a year or
two afterward.

But it is also a fact that NASA continually tweaked the foam after that,
and by 2000 had gotten TPS damage down to pre-1997 levels.

And it is also a fact that the change in blowing agent did not affect hand-
sprayed foam like the bipod ramps and PAL ramp. Therefore, the statement
that the change to "environmentally friendly foam" contributed to the
Columbia accident (or the PAL ramp loss on the current flight), either
directly or indirectly, *is* an urban legend.

--
JRF

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