From: X@xer.com   
      
    wrote in message   
   news:1130863647.705686.293190@g47g2000cwa.googlegroups.com...   
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   Others have given the particulars on how much O2 a person need, and how much   
   CO2 will cause unconsciousness and death quickly.   
      
   If you have the available equipment CO2 is very easy to strip from an   
   atmosphere. It just requires a 'little' atmosphere processing.   
      
   If your protoganists have the time / equipment / motivation / energy /   
   sufficiently large heat sink all they need to do is routinely cool some part   
   of the atmosphere to  ?78 °C. The CO2 will sublimate out as dry ice. Then   
   all you have do is sweep it up and put it somewhere air tight and safe where   
   it can't contaiminate the rest of the air supply.   
      
   If your protoganists have already gone the route of having to cracking water   
   via electrolisys to get their O2 then they can of cause burnt the CO2 and H2   
   produced in something called a Sabatier reactor. Out comes some H2O (that   
   can be reprocessed for electrolisys and much methane. Methane is slightly   
   easier to store (if you have big strong pressure vessels and refridgeration   
   gear) than dry ice. And if you get really deseperate you can invest a big   
   chunk of energy in pyrolising (burning with out oxygen) the methane and   
   getting carbon ash and H2, which you can send back to the Sabatier to turn   
   more CO2 in to Methane and H2O.   
      
   But for small groups of people, small spaces, and shortish periods of time   
   just putting a refridegration unit in the air conditioning loop is probably   
   easier ;-). And vent the dry ice via the toilet or put it in the airlock.   
      
   For more info on the Sabitier/electrolisys process look up Robert Zubrin's   
   Mars Direct proposal.   
      
   Regards   
   Frank Scrooby   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)