turntable nightmare
"Karl Uppiano" wrote in message
news:UJGch.644$4p2.376@trndny07...
Columbia burned up on re-entry in part because flight management at
NASA
became complacent about "foam shedding" from the main hydrogen tank.
Seems to me the poor O-ring sealing, foam shedding, and fragile heat
tiles
are all engineering problems.
(partly caused by lack of money maybe, but everything is built to a
budget).
You can only be complacent about a problem where one already exists.
True, but engineers are paid to provide solutions and give advice. Most of
the time, we are given conflicting requirements, including cost and
schedule. It is all a trade-off. We have to find the best solution within
the given constraints. Space flight has a vary narrow solution space
within
very tight constraints.
All true, but does contradict your original claim though.
In the case of the o-rings, the engineers' advice was "don't fly". Flight
management ignored that advice with predictable results. I'd say that was
good engineering and poor management.
I'd say it was poor engineering originally, poor management, and lack of
money to fix the problem when the engineers did realise there was a problem
with their original design..
In the case of the heat shield tiles, there simply aren't many solutions
that fulfill the requirements to be heat resistant, lightweight, and
rugged.
As long as nothing hits them on take-off, they work just fine.
And as long as they don't fall off by themselves as many did with the
original adhesives.
So the only big problem is falling ice and foam. When the engineers say "we
need to
solve that" or "we're running too close to the wire" and management says
fly
anyway, that's a management problem. Risk management.
Sure, there's always a compromise between perfection and budget in the real
world.
Do we have the best engineered spacecraft possible? Probably not. Is it
poorly engineered? I don't think so. We could probably do better today,
Ah, then your original example/assertion was wrong, and irrelevant the the
original discussion anyway.
That was my point.
MrT.
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