Greetings to all,   
      
   I recently read Andy Wier's "The Martian". I haven't seen the movie, and the   
   copy of the book was the 'student-friendly' version. Warning this post   
   contains spoilers. I warned you.   
      
   The book opens with a monster dust storm that Andy Wier admits was   
   ridiculously 'sexed up' for the drama.   
      
   A couple of other things bothered me.   
      
   The Hab as described is essentially a highly pressurized tent. That might seem   
   great on the mass saving side of things ... but as demonstrated in the text,   
   super canvas might not be the best solution for your Martian surface habitat   
   needs. Is there any    
   serious real world mission proposal that suggest putting future Mars explorers   
   in such delicate housing. Or did Andy Wier just do this to add to the drama?   
      
   Would the light levels in the Mars Hab be sufficient to coax enough   
   photosynthesis out of the potato plants? Plants sre naturally adapted for   
   Earth average light (average 800 watts per M^2 peaking at 1300 watts per m^2,   
   I think). Mars averages 400 watts    
   per m^2 if I remember correctly. From one of the images from the movie that I   
   found it does look like the hab has a transparent top that will let in natural   
   light but that still leaves the plants at 50% deficit. Having every light bulb   
   available running    
   might help.    
      
   The hydrazine into water thing, and the subsequent explosion / fire. If you   
   are going to do something stupid (and dangerous) like decomposing a rocket   
   fuel and burning the hydrogen you do it:   
      
   (a) somewhere that isn't your only available home.   
   (b) inside a solid container   
   (c) very, very slowly with lots of cold buffer gas (like Mars' natural CO2   
   atmosphere.   
      
   Do the crazy experiment inside the wrecked lander's pressure vessel. According   
   to the text the catalyst produced hydrogen (and not the ammonia that hydrazine   
   could also produce). You don't burn hydrogen when you have FUEL CELLS. You use   
   the hydrogen to    
   top up the fuel cells' fuel. With some luck the extra electricity produced   
   with cover the energy cost of running the oxygen generator to produce the   
   extra oxygen that the fuel cells need to react with the hydrogen.   
      
   Or is this just another example of Mr. Wier adding to the drama?   
      
      
   My last quibble is hydrogen again. At the end of the book NASA instructs Mark   
   Watney to build an improvised electrolysis rig to turn all his available water   
   into hydrogen for the Mars Ascent Vehicle fuel factory to turn into methane.   
   BUT IF YOU HAVE A    
   working MAV you should have an excellent electrolysis rig already. Let me   
   explain:   
      
   The theory is that the MAV is sent two years ahead of the mission that will   
   use it and spends those two years turning 6 tons of hydrogen into 100 odd tons   
   of methane (CH4) and liquid oxygen (O2). The reaction to do this is:   
      
   CO2 + 4H2 → CH4 + 2H2O   
      
   To get at the hydrogen now 'wasted' in the water (the H2O), the MAV would have   
   to have a electrolysis.    
      
   All in all I enjoyed the book more than any recent offers in the semi-hard SF   
   market. Thank you to Andy Wier for entertaining me AND making me think.   
      
   Is there anything I missed?   
      
   Any comments welcome.   
      
   Regards   
   Frank Scrooby   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)