From: ihatespam@period.com   
      
   "Carey Sublette"  wrote in message   
   news:02jCb.121$0s2.17@newsread2.news.pas.earthlink.net...   
   > But it should be noted that the explosion of a bi-propellant rocket is   
   > actually quite unlike the detonation of a high explosive, since the energy   
   > release is limited by the mixing of the fuel and oxidizer and cannot   
   > detonate all at once. The example of the Challenger illustrates this quite   
   > well. Despite ripping up in a hypersonic airstream, which probably   
   > accelerated the mixing (I would think), it did not generate a high   
   pressure   
   > blast wave, which would have pulverized the cabin instantly. The   
   astronauts   
   > are thought to have survived all the way down to the ocean surface.   
   >   
      
   Technically, Challenger did not "blow up".  NASA's frame-by-frame analysis   
   of the launch video shows that the ET collapsed when the O2 tank was   
   punctured by the nose of the SRB (which had pivoted around the forward   
   attach point after the aft burned through).  This resulted in the sudden   
   release of a lot of gas at cryogenic temperatures, which immediately   
   condensed all of the atmospheric water in the area.  The result looked like   
   a cloud of white smoke, but there was no evidence of combustion of the LH2.   
   There's a small orange/yellow fireball visible in part of the cloud that's   
   thought to be the detonation of the hydrazine from the OMS tank when it came   
   in contact with the condensation (hydrazine and water don't get along well),   
   but even that failed to set off the LH2.  If there had been an LH2   
   explosion, there probably wouldn't have been a cloud (the combustion product   
   is water vapor).   
      
   The real damage was done by the supersonic slipstream, which shredded the   
   orbiter's airframe as soon as it started to tumble.   
      
   > For monopropellant engines, its a different matter.   
   >   
   Depends.  If you're talking about a monopropellant/catalyst (like hydrogen   
   peroxide and silver), there won't be any explosion. If you're talking about   
   a solid rocket like the Shuttle SRBs, the energy release is proportional to   
   the surface area of the combustion zone; if something happens to shatter the   
   propellant mass (creating a sudden, dramatic increase in the size of the   
   combustion zone), you'll get an explosion, but unless you've pulverized the   
   propellant, it'll still be a fairly small fraction of the total propellant   
   available (of course, the rest of the propellant will rain down as flaming   
   chunks, which happened in Guyana).  The SRB fuel is supposed to have the   
   consistency of a pencil eraser, which I'd guess would be fairly hard to   
   shatter.   
      
   --- SoupGate-Win32 v1.05   
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