From: spike66 (spike66@attbi.com)
Date: Sat Feb 01 2003 - 13:52:42 MST
Technotranscendence wrote:
> On Saturday, February 01, 2003 12:06 PM Kai Becker kmb@kai-m-becker.de
> wrote:
>
>>Very sad news. German TV shows specials
>>about it since 16.30 MET. The Columbia was
>>22 years old. Has anything been modernized
>>since '81?
>
> All the shuttles, IIRC, have been upgrade several times. Just
> recently -- was it 2000? -- Columbia was overhauled. Last year, too,
> cracks were found in fuel lines. I forget what was done with these.
Metal fatigue is the way mechanical engineers
describe the weakening of metal under repeated strain.
Steel eventually reaches a final minimum strength
regardless of the number of cycles, but aluminum keeps
getting weaker and weaker indefinitely. This always
gives me pause whenever I fly in bad weather, especially
on an older plane. Aluminum is the metal which
makes up the structural elements of the space
shuttle. Cracks get started, then they propagate.
The higher the stress level, the faster the fatigue
curve advances. The shuttle flies inherently close
to the material limits. Sooner or later, that
structure will fail catastrophically.
This day I am devastated and heartbroken, but I
cannot say I am shocked or surprised. spike
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