Range Safety System cause Challanger Explosion?
Robert O. Domitz
entitled "Did On-Board Self-Destruct System Cause Space Shuttle
Explosion?"
According to this article, the range safety system uses a very
powerful explosive, HMX (cyclotetramethylenetetranitramine), as the
destruct mechanism. This explosive has an extremely low ignition point
of 350 degrees F!! This is lower then the ignition point of paper (450 F)!
The article shows, in color, where each of the explosive packages are
located on the solid rocket boosters and on the external tank. On the
external tank, the explosive is a twenty-foot long shaped charge which
is intended to split the liquid hydrogen section of the tank. This
strip of explosive is located in a open tray running down the right
side of the tank. This strip was located only thirteen to fifteen
feet from the failed booster seal.
The article goes on to note that near the failed booster seal are the
three struts which attach the solid rocket boosters to the external
tank. These struts contain a different explosive, NHX, which is used
to separate the boosters from the external tank. NHX has a thermal
ignition point of about 1000 degrees F. Had this happened, it would
support the thesis that the lower mounting point failed and swiveled
the solid rocket booster into the top of the external tank.
According to the article, the flames escaping from the failed booster
seal were superheated to approximately 6000 degrees F. According to
the article, either or both of the explosives could have detonated.
Robert Domitz ...{decvax,ucbvax,ihnp4}!vax135!petsd!pecnos!rod
Concurrent Computer Corporation
(a Perkin-Elmer company)
106 Apple Street
Tinton Falls, New Jersey 07724
201-758-7296
The opinions expressed above are totally disclaimed by my employer,
my wife, my dog, and myself.
(donchajustlovit?!)
Alan Marcum
> The ELECTRONIC ENGINEERING TIMES, March 24, 1985, contains an article
> entitled "Did On-Board Self-Destruct System Cause Space Shuttle
> Explosion?"
>
> seal were superheated to approximately 6000 degrees F. According to
> the article, either or both of the explosives could have detonated.
And in <1...@axiom.UUCP>, paul@axiom (Paul O`Shaughnessy) writes:
> [again, paraphrasing from the EE TIMES article]
> Former section chief of test engineering for shuttle destruct systems
> electronics proposes that on-board HMX explosives could have been ignited
> by flame from starboard SRB. These explosives were located on the external
> fuel tank 15 feet from the flaw in the starboard SRB and can be thermally
> ignited at 350 degrees F.
> The engineer was employed by United Space Boosters Inc., under contract to
> NASA, from 1981 to 1982.
Now wait just a minute. Does anyone else think the headline is a tad
misleading, at best? Regardless of the range safety system, there was
a serious flaw with the right SRB. Regardless of the presence or
absence of the range safety system explosives, Challenger was in
trouble.
--
Alan M. Marcum Sun Microsystems, Technical Consulting
...!{dual,ihnp4}!sun!nescorna!marcum Mountain View, California
g...@cbmvax.uucp
> entitled "Did On-Board Self-Destruct System Cause Space Shuttle
> Explosion?"
>
> According to this article, the range safety system uses a very
>
> According to the article, the flames escaping from the failed booster
> seal were superheated to approximately 6000 degrees F. According to
> the article, either or both of the explosives could have detonated.
>
> Robert Domitz ...{decvax,ucbvax,ihnp4}!vax135!petsd!pecnos!rod
This is one of the most questionable articles about the shuttle disaster that
I have read. It makes a big fuss about the presence and positioning of the
destruct charges without really addressing the question of whether a SRB seal
failure would have ruptured the external tank and caused an explosion without
the presence of the destruct charges.
Those charges are there for a reason after all. There are damn few pilots
who would have their craft plop down on a school or urban area at the cost of
saving their lives.
All this post-explosion analysis and finger pointing seems to be going downhill
with the target being no shuttle flights for years, and no space station this
century... Anybody remember their feelings during the initial press conference
when someone popped the question of external tank damage and Jess Moore replied
something along the lines of 'we evaluated that and *I* gave the go-ahead'...
--
George Robbins - now working with, uucp: {ihnp4|seismo|caip}!cbmvax!grr
but no way officially representing arpa: cbmvax!g...@seismo.css.GOV
Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
Paul O`Shaughnessy
Alan Marcum @ Sun Microsystems in 34...@sun.uucp writes in reply to
two postings on the possible role of on-board explosives,
>Now wait just a minute. Does anyone else think the headline is a tad
>misleading, at best? Regardless of the range safety system, there was
>a serious flaw with the right SRB. Regardless of the presence or
>absence of the range safety system explosives, Challenger was in
>trouble.
Actually, yes. I agree, and I was one of the original posters, although
I can't take credit for the title. The EETimes article does have a whiff
of sensationalism to it, and there's little doubt that the SRB is the real
culprit. However, the one plausible part of the article is that the flames
detonated certain critical structural parts, particlularly the lower
attachment point of the starboard SRB. No doubt that NASA's job is to stop
the boosters from leaking in the first place, but each step in a chain
reaction is important to understand and then correct, if such a correction
would make the system significantly more robust.
****************
Paul O'Shaughnessy @ Axiom Technology, Newton MA
Home of the 'Management Team'
{decvax,ihnp4,utzoo}!linus!axiom or
{bellcore!topaz,seismo}!harvard!axiom on UUCP