From: junkmail@wolfkeeper.plus.com   
   Copy: sci-space-tech@moderators.isc.org   
      
   Paul F. Dietz wrote:   
   > Huh?  Titanium the metal is common wherever you want to make it.   
   > It doesn't occur at all in nature.   
   >   
   > What may have been short was *refining capacity* in the US,   
   > but that's obviously not an insurmountable obstacle.   
      
   No, there are no insurmountable obstacles to building titanium vehicles.   
      
   There are a number of difficulties:   
      
   a) the best ore is more common in non US countries, noteably Russia   
   b) US workforce experience with dealing with titanium was not high   
   c) titanium swarf is explosive   
   d) titanium requires specialist equipment to work, it's far less workeable   
   e) welding is more difficult than steel or aluminum   
   f) it's harder to refine   
      
   All of this pushes up the costs and decreases availability.   
      
   Problem a) was very significant at the time- the Russian block countries   
   had access to most of the alloys that were useable for building   
   vehicles. The titanium SR71 was built using material obtained using   
   clandestine means from Soviet companies.   
      
   A nickname for titanium was 'unobtainium'.   
      
   As I understand it, problem b) was perceived to be quite important when   
   building the Shuttle- workforce that had direct experience with titanium   
   were mostly assisting with black programs.   
      
   Note that the soviets who had greater access to titanium, didn't use it   
   very much, preferring to use much cheaper steel.   
      
   >     Paul   
      
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