XPost: sci.space.policy   
   From: larryg@u.washington.edu   
      
   On Wed, 15 Mar 2006, Jim Davis wrote:   
      
   > Date: Wed, 15 Mar 2006 19:41:29 -0000   
   > From: Jim Davis    
   > Newsgroups: sci.space.policy, sci.space.tech   
   > Subject: Re: Fire in the sky, O'Neill colonies and asteroids   
   >   
   > Lawrence Gales wrote:   
   >   
   >> For the 1st colony I select 1500 feet in major diameter and 43   
   >> feet in   
   >>      minor diameter, so using strict scaling it should be   
   >>      (1/4)*(1/10)*(1/10) = 1/400 of the mass of the Stanford   
   >>      torus (the last (1/10) occurs because the tube would be   
   >>      1/10 as thick as well as 1/10 as wide).  This yields a   
   >>      structural mass of 625 tons, but we will set it at 1000   
   >>      tons to be conservative.   
   >   
   > Some comments:   
   >   
   > 1. You've gone from 1 rpm from the original Stanford design to 2 rpm   
   > in your scaled down design to maintain 1 g. That will probably not be   
   > acceptable.   
      
   ======================================   
   Well, O'Neill believed that it was acceptable, and it is my undestanding   
   that most people be can be accustomed to 3 rpm, so 2 rpm should not be a   
   stretch   
      
   =================================================   
      
      
   >   
   > 2. 1000 tons is about 5 times the mass of ISS and yet you intend to   
   > accomodate 200 people?   
      
      
      
   =====================================   
   That is the raw structural weight w/o air, water, soil, shielding, etc.  I   
   scaled it from the Stanford Torus which had 250 times the weight, but   
   based   
   on other scalings that I saw on the Stanford Torus website (which seems to   
   have disappeared) it seems reasonable.  Note that the 10,000 person torus   
   offered huge open spaces and nearly luxury living, whereas this initial   
   colony is more of a construction shack.  It does offer nearly 1000 feet^2   
   per person   
   =====================================   
      
      
   >   
   > 3. 1000 tons is about 4 times the mass of the Airbus A380 which cost   
   > about $12 billion to develop and build and yet you estimate your   
   > first torus cost at $3 billion?   
   >   
   > Jim Davis   
   >   
   ======================================   
   I specifically stated that I did not include development costs -- only   
   production and transport costs.   
      
      
      -- Larry   
      
   ================================================   
      
   >   
      
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