[Vwdiesel] Rabbit droppings --OT ----( The Discovery take off ? )
gavrik at cablespeed.com
Tue Aug 2 19:16:28 EDT 2005
>NASA ignored a guy saying the "O" rings are not tested for >the low temperature launch.
I hear that there was more to the Challenger disaster then
cold o-rings. I was my understanding, that before the
launch of the Challenger, the engineers at Thiokol warned
NASA that the propellant in the solid rocket boosters was
too cold for a safe launch.
The story goes like this:
When Thiokol cast the fuel in each section of a SRB they
control the dimensions so when the sections are joined the
fuel grain is in compression where it butts up against the
adjoining fuel grain. As long as this seam is in
compression the fuel does not burn on these surfaces and
the grain burns as though it was continuous. As the
temperature goes down the fuel grain shrinks relative to
the rocket body. If the temperature gets low enough the
this compression goes to zero and the adjacent sections of
fuel start to separate creating a crack. If these exposed
surfaces start to burn, the rocket body joints are
subjected to high temperatures that they would normally
only experience in the last seconds of a burn.
Is this true? Does anyone know about this? I would think
that Val Christian might have an opinion.
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