XPost: sci.space.policy   
   From: zenadsl6186@zen.co.uk   
      
   Mike Miller wrote:   
      
   > henry@spsystems.net (Henry Spencer) wrote in message   
   > news:...   
   >>   
   >> If you did pressurize the whole tube, almost certainly you would first   
   >> coat the walls with a sealant of some kind.   
   >   
   > A sealant and pressure vessel.   
   >   
   > I wouldn't want to depend on brittle rock holding in 4 or 14.7psi.   
   > While the weight of rock overhead might be enough to contain that,   
   > you're still introducing new, large tensile and hoop stresses to   
   > brittle material.   
      
      
      
   Build big and flat, say 1 mile square and twenty feet high. Put 60 feet of   
   regolith/powdered rock roof/shielding on top, and one atmosphere of pressure   
   will support it.   
      
   You could use ropes in tension to keep the roof down, if it was only 40 feet   
   thick.   
      
   It's a different kind of architecture ...   
      
   -- Peter Fairbrother   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)