From: spam@merlyn.demon.co.uk   
      
   JRS:  In article , seen in   
   news:sci.space.science, Gordon D. Pusch  posted at Tue, 6 Apr 2004 21:08:29 :   
      
      
   >Your proposal is not _totally_ implausible. The energy required to climb   
   >a beanstalk is only a small fraction of the energy required to accelerate   
   >a payload into Low Earth Orbit; the fuel and oxygen tankage required   
   >would be large, but not prohibitively so.   
      
      
      
   Earth radius is 7 Mm, GSO radius is 42 Mm, so in units of the Earth's   
   radius 1 and 6.   
      
   Potential energy in an inverse square field is inverse linear, so with   
   it being zero at infinity, it is 1/6 at GSO and 1 on the ground,   
   difference 5/6.   
      
   But the energy required for LEO is half that for escape, so climbing the   
   stalk to GSO requires 5/3 of the energy to LEO.   
      
   "Centrifugal force" will supply a significant part of that energy (by   
   lengthening the day), but not enough to leave only a small fraction.   
      
   Much of the fuel and oxygen will need to be lifted, though there is the   
   advantage that the exhaust need only carry a little energy other than   
   that of height.   
      
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