On 2012-02-11 18:53:22 +0000, Val Kraut said:

" In retrospect we know that the O-ring issue that destroyed Challenger
was inevitable. It had almost happened in earlier flights and would
likely have happened on some winter day sooner or later.

Supposedly there were partial burn throughs on recovered boosters - but
NASA didn't wake up to the real potential until they actually lost a
vehicle. There was an interesting article on the mind set people get
into - Hey worked the last 24 times we did it - we're on a roll!

Not "supposedly", it is well documented. My point is that STS-51L
nearly got away with it. The o-ring failure did not cause the disaster
alone. Had the windshear at T+55 seconds or so not reopened the leak
(this was the strongest windshear the Shuttle has ever experienced,
before or after Challenger), Challenger might have squeaked by and
survived. But that level of damage, with *both* o-rings having failed
(a first) would certainly have given the engineers the ammunition they
needed to suspend flights until a fix could be implemented. NASA would
have screamed bloody murder about missing the Galileo and ISPM
deadlines, but they would have been out of their "the backups kept us
safe" counter-arguments. The engineers would finally have their
evidence that the design was unsafe, which is what they didn't have in
hand on the night of January 27-28, 1986.

An interesting what-if.

Brian