HOST Comp JimS wrote:   
   >   
   > >I would like to know why we don't travel to Mars   
   > >by first lifting many loads of fuel to the space   
   > >station.  The actual spaceship would be assembled   
   > >in space... 20 to 50 trips would be necessary...   
   >   
   > Perhaps something like that will be done someday, but   
   > there are some disadvantages. For one thing, storing   
   > tons of flammable fuel at a space station might be somewhat   
   > dangerous. Also, assembling things in space is a slow,   
   > difficult process. And the cost of making 20 to 50 trips   
   > would be huge.   
      
   But how does the cost, and time, compare with making one trip with 20 to   
   50 times the total mass?  Can we even do it?  It needs a detailed   
   systems study, which probably has already been done.  If not, why not?   
   If so, I would like to know the results.   
      
   I think the fuel danger is not excessive.  The fuel containers could be   
   kept at a considerable distance from the station, on a wire heading   
   toward the earth.  Tidal forces would keep the wire taught.  That might   
   be necessary if they were solid fuel, which could explode if hit by a   
   micro-meteorite.   
      
   OTOH, if the fuel was two components, say oxygen and hydrogen, then   
   neither oxygen tanks not hydrogen tanks are explosive on their own.  To   
   keep them cold in space mainly requires sheilding from sunlight.   
      
   m   
      
   --   
   "Many are stubborn in pursuit of the path they have chosen, few in   
   pursuit of the goal." - Friedrich Nietzsche   
      
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