"Rand Simberg" wrote in message
...

My only thought (and I don't have a copy of Jenkin's with me in DC) is
that
Jenkin's mentions each airframe is carded at something like a 1.6 load
factor (I may be using the wrong term). But pretty much, the rest seems
to
be nebulous numbers like, "100 uses" for the SSME, etc.

The load factor (actually structural safety factor, or margin) is 1.4

Hmm, thought it was 1.2 on Columbia and the later OVs had been built to 1.6
and Columbia upgraded.

(the difference between manned aircraft and rockets, which are less,
but I can't remember the number), but that's not really on point.
Thanks for the try, though.


Actually it sort of was. My point was basically that that's the ONLY number
I've seen that has any sort of documentation.

The 100 flights, 10 years I think was like the numbers that Feynman mentions
on chance of a disaster. Basically made up and wishful thinking.

In fact, I can't really think of any real way that the "100 flights" number
could be any more than a "made up" number. There's no real database to
compare against. And given the generally mild conditions the orbiters fly
in, I can't really see that number couldn't be 200, 500 or even 1000.

Now, the "10 year" number I can see based on the known aging of materials,
but then again, that's hard to judge because there's not much of a database
to compare against.


My thesis is that all this talk about "recertification" of the Shuttle
to fly it past 2010 is post-Columbia hooey, but I'd like to verify
that.

I tend to agree and Jorge has posted previously that some have argued all
the work after Columbia is essentially equivalent to a recert anyway.


--
Greg Moore
Ask me about lily, an RPI based CMC.