Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!wasatch!utah-gr!uplherc!sp7040!obie!wes
From: wes@obie.UUCP (Barnacle Wes)
Newsgroups: sci.space.shuttle
Subject: Re: Discovery's launch: Am I imagining things?
Summary: Burn-through data misrepresented...
Message-ID: <215@obie.UUCP>
Date: 7 Oct 88 05:36:18 GMT
References: <1104@cfa237.cfa250.harvard.edu> <15722@ames.arc.nasa.gov> <5488@ecsvax.uncecs.edu>
Organization: the Well of Souls
Lines: 28

In article <5488@ecsvax.uncecs.edu>, ruslan@ecsvax.uncecs.edu (Robin C. LaPasha) writes:
> Tonite on the news I heard that NASA had found no evidence of a burn-through
> fire on the recovered SRBs.  Let us frigging hope they're right.
> Geez, how could you have burn-through with the new flange and three-ring
> system?  If it happened, we can all look foward to another two and a half
> years of frustration and (hopefully) the death sentence for the managers
> at Morton Thiokol.

The previous burn-throughs noted on the SRBs (yes, there *were* previous
burn-throughs) did not occur in the flanges and o-ring assemblies.  The
burn-throughs occurred in the case walls near the point where the case
skin flared out to accept the flange.  The flanges are much stiffer than
the case walls, and this causes flexing during the flight.  The case
walls crack due to the flexing, creating a weak spot.  The internal
pressures of the booster will cause a burn-through at this point IF the
crack occurs early enough in the flight.

I'm sorry I don't have the reference for this information with me right
now, I have it at work.  I can post it (or e-mail it) if anyone is
interested.  Note that this design flaw in the SRBs still exists, and
may even be WORSE with the new thicker, stronger, and STIFFER flange
assemblies.

-- 
                     {hpda, uwmcsd1}!sp7040!obie!wes

         "How do you make the boat go when there's no wind?"
                                 -- Me --