[AR] Re: shuttle SRBs (was Re: Re: Phenolic regression rate)
- From: Norman Yarvin <yarvin@xxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Wed, 7 Feb 2018 19:17:57 -0500
On Wed, Feb 07, 2018 at 02:46:45PM -0700, William Claybaugh wrote:
Not quite. For the specific Ares 1 case, fragmentation of the forward
bulkhead could send debris through the upper stage and hit the back of the
capsule before it had gotten away if the capsule was using liquid rocket
escape rules.
That makes it sound like the main determining factors were the Ares 1
solid motor being larger and closer, as compared to typical strap-ons
which are smaller and farther away.
If we assume that the timing between event initiation and escape system
activation is the liquid rocket standard ( as I recall, 150 milliseconds)
and if we assume the liquid rocket standard 15 g escape acceleration then
there is no known solid strap-on failure that the escape system can't
outrun.
That's a pretty fast response time; one certainly couldn't have a
human in the loop, for instance. Even so, in the event of a case
rupture, at a speed of sound of 330 m/s, in 150 ms a blast wave front
has time to cover fifty meters. Perhaps the idea is that it's not the
blast that gets you, it's the shrapnel, and the shrapnel would be
slower than that?
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