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From: ucc1q@elroy.uh.edu (A JETSON News User)
Newsgroups: sci.space.shuttle
Subject: Re: Shuttle engine failure on the pad
Message-ID: <5840.26018bba@elroy.uh.edu>
Date: 17 Mar 90 06:58:33 GMT
References: <140@caslon.cs.arizona.edu>
Distribution: usa
Organization: University of Houston
Lines: 32


 In article <140@caslon.cs.arizona.edu>, kevin@cs.arizona.edu (Kevin Strietzel) writes:
> Here's a query that's been bumping around my skull for a few years now:
> 
> What happens if one SRB ignites, but the second won't go?

 1. You are talking about millions of pounds of thurst from a single SRB.
   In one seconds time you will have such a tilt to one side that the entire
   group of oribter/ET/SRB's will fall over sideways. I doubt that the SSME's
   have enough thurst at max power to prevent the tilt. Even it the SSME's do
   have enough thurst they can not be steered far enough to provide enough
   side thurst to balance enough to climb as little as one thousand feet,
   much less ten or twenty thousand. Remember, the French lost an all
   liquid fuel launcher and payload when ONE engine lost HALF its thurst.
   So what you get is everything trying to fly sideways, falling over and
   destroying pad/orbiter/ET ( remember, a FULL ET, not half? empty).
 2. Enough if you can steer the SSME,s enough to balance, it has to be done
   QUICK. I do not believe the system can react fast enough to such a 
   sudden imbalance of that size.
 3. if you can balance fast enough you will still start flaying sideways
   so far so fast that you have a 50/50 change of hitting the tower. That
  depends on which side the failed SRB is on.

  Lose an SRB on the pad and everything is slag and vapor. However, NASA
  does know that both SRB's MUST fire and the igniters in them are massively
  overpowered and have many duplicate firing charges. The igniters are
  muliti-staged: several small igniters to light several larger ones to
  light the main igniter that lights the SRB proper. I do not remember 
 the full layout on this but i have the general idea down right.

  i am not an expert. these are my opinions. I think the SRB's will light.
  If not it was sabotage. if one does not light, the crew aboard is DEAD.