"Terrence Daniels" writes:

"Scott M. Kozel" wrote in message
...
"Nobody on this team believed that foam could hurt the orbiter, could
hurt the RCC at all," a person who has worked with the investigation
said, referring to the reinforced carbon carbon in Columbia's left wing.
"They had one fundamentally flawed understanding: that foam couldn't
harm RCC, and that colored everything else."

Right, and then - here's me trying to understand this from an engineering
point of view - the best thing to do at that meeting would have been to ask
the people making the presentation, "How exactly did you determine that
there's no possibility of damage?" with a follow-up about "What about the
RCC?" Am I right?

I think so.

And then if you found out that nobody had ever done any testing on the
RCC... You'd be making some pretty big assumptions on no real data, just a
"gut feeling."

Not trying to fry anybody, I just want to understand what the RIGHT thing to
do would have been in that situation.

I think these were the flaws in the process: although the foam was not
supposed to shed, it *did* shed, and this was accepted. Most of this
acceptance seems to have been the result of thinking "it hasn't hurt
yet, ergo it won't hurt in the future". The modelling which was done
was insufficient to adequately answer, with a high degree of confidence,
what kind of damage foam could cause. The CRATER modelling, which was
used to try to determine the damage the foam could cause to the tiles,
was based on extrapolating from micrometeorite studies which used
impactor sizes far outside the range which were resulting from the foam
shedding, and it's hard to see how there could be confidence in the
conclusions reached as a result of that. In fact, some of the studies
concluded that the the tiles would be completely penetrated, but for
some reason these were ignored and the conclusion was stated that some
tile would remain, sufficient to prevent loss of vehicle. The
post-flight testing apparently has shown that, in fact, the foam was
unlikely to have caused catastrophic damage to the tiles, but I think
NASA was lucky that their flawed reasoning (IMO) ended up giving a
correct result. They weren't so lucky when it came to the RCC: the
conclusion, as near as we can see based on no relevant testing, was that
foam couldn't do more that scratch the RCC leading edge of the wing.
This turned out, as we have seen, to be wildly off the mark.

So, in my opinion, the right thing to do would have been to take the
foam shedding more seriously, and take more stringent steps to ensure it
wouldn't shed, and not fly until you were reasonably certain it
wouldn't. Failing that (and I think this would have been a mistake),
you really have to understand what kind of debris events you're likely
to see, under what circumstances, and what kind of damage these might
cause. None of this was done, as near as we can tell. When *this*
event was seen, and questions were asked about what it might mean, the
rationale for conclusions should have been questioned, to ensure that
this wasn't a case of garbage in, garbage out, or wishful thinking.
Not all of these failings are the MMT's, the lower level meetings should
have been doing this.