From: niklas.holsti@tidorum.invalid   
      
   On 2020-06-28 22:12, JF Mezei wrote:   
   > Did some reading (danger will robinson, danger !)   
      
      
       [snip]   
      
   > I also know from the specs that O2 will liquify at -183°C at a presusre   
   > of 1 atm (14.7 psi).   
   >   
   >   
   > So if you have a good refrigirator, you could keep your liqiud oxygen in   
   > a plastic bottle without any pressure at -183.   
      
      
       [snip]   
      
   > So in the context of going to Mars where you need to keep that O2 for 6   
   > months without venting, what sort of strategies are possible?   
      
      
   Who says "no venting"? Of course you can vent some of it, if it is   
   included in your propellant calculations. The amount of venting is about   
   proportional to the amount of heat you let into the tanks -- no heat, no   
   venting; a little heat, a little venting.   
      
      
   > On the trip to Mars, won't the ship be constantly exposed to the   
   > sun?   
      
   In the SpaceX videos of Mars trips (quite old already...) the Starship   
   points its rear end (rocket end) at the Sun, and moreover deploys from   
   that rear end a large solar-electric array that seems to shadow most of   
   the ship, even if there is some deviation from the rear-end-to-Sun   
   attitude. Most of the surface of the propellant tanks therefore sees   
   only deep space, at a few degrees K.   
      
   (Sadly, the need to keep the propellant tanks in shadow is an obstacle   
   to having artificial, rotation-induced gravity for the Mars trip.)   
      
   --   
   Niklas Holsti   
   niklas holsti tidorum fi   
          .      @       .   
      
   --- SoupGate-Win32 v1.05   
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