From: alcore@uurth.com   
      
   On 7 Dec 2004, jmbrock@gmail.com wrote:   
      
   >Has anyone here heard of a mass driver?   
   >   
   [snip]   
   >   
   >Anyone have any thoughts on this?   
      
   One of the big problems with Mass Driver launch is the fact that if you   
   launch something at sea level with enough energy to significantly reduce   
   the size of the booster, you have a *serious* air friction problem.  (It's   
   as bad or worse than the re-entry scenario... and now you also have to   
   protect your fragile booster from all this heat and dynamic stress on the   
   structure.)   
      
   While this can be reduced by building at higher altitude, it doesn't help   
   much until you get up to a release altitude that is taller than even Mt.   
   Everest...   
      
   The other serious problem is g forces at launch.  Either you've got to   
   build a launch track that is more than 10 miles long, or you are going to   
   subject the payload (and any people aboard it) to launch forces at   
   EXTREMELY high g acceleration rates.   
      
   The space shuttle pulls 6-10 gs on launch and sustains this over a period   
   of several minutes and over a distance of hundreds of miles...  But with a   
   mass driver, all of this acceleration takes place in several SECONDS on a   
   launch track that is relatively short.  Put very simply, you are going to   
   squash everything aboard that isn't tredendously strong into jelly...   
   particularly people.  This system simply won't work for anything that's   
   fragile.   
      
   Mass drivers may one day be a useful and commercially viable bulk cargo   
   launch system.  But they cannot replace more "gentle" launch methods   
   needed for fragile instruments and people.   
      
   Gene Pharr   
   Slidell LA   
      
   --   
   Alcore Nilth - The Mad Alchemist of Gevbeck   
   alcore@uurth.com   
      
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