rod@pecnos.UUCP (Robert O. Domitz) (03/27/86)
The ELECTRONIC ENGINEERING TIMES, March 24, 1985, contains an article 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?!)
marcum@sun.uucp (Alan Marcum) (03/28/86)
In article <158@pecnos.UUCP>, rod@pecnos (Robert O. Domitz) writes: > The ELECTRONIC ENGINEERING TIMES, March 24, 1985, contains an article > entitled "Did On-Board Self-Destruct System Cause Space Shuttle > Explosion?" > > 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. And in <192@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
grr@cbmvax.UUCP (03/30/86)
> The ELECTRONIC ENGINEERING TIMES, March 24, 1985, contains an article > entitled "Did On-Board Self-Destruct System Cause Space Shuttle > Explosion?" > > According to this article, the range safety system uses a very > powerful explosive... > > 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!grr@seismo.css.GOV Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
paul@axiom.UUCP (Paul O`Shaughnessy) (03/31/86)
Alan Marcum @ Sun Microsystems in 3412@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