XPost: sci.space.policy, sci.physics   
      
   In sci.physics "Greg \(Strider\) Moore"  wrote:   
   > wrote in message news:3st7dd-5si.ln1@mail.specsol.com...   
   >>   
   >>> Nor will you need one! I mean ISS provides its complete power for the US   
   >>> section at 120kw.   
   >>> So small reactor, or a bunch of relatively cheap solar panels.   
   >>   
   >>Sigh.   
   >>   
   >>Mars is much farther from the Sun than ISS and has an atmosphere, the   
   >>net results of which is that there is far less power available on the   
   >>surface of Mars than there is at the ISS.   
   >>   
   >>To get an average daily output of 120 kW on Mars you need about   
   >>3,000 square meters of solar panels.   
   >>   
   >   
   > Umm... yeah... your point?  Hell I'm seeing HOUSES down the street near me   
   > that have nearly that much (seriously there's one house that a quick   
   > ball-park estimate suggests they probably have about 2x the panels they   
   > need).   
   > Quick googling shows that I can get a 2 square meters of panels at $218.  So   
   > that's $327,000.  For a mission cost in the millions, that's pretty cheap.   
   > Heck, even with delivery costs (let's assume $1K/kg, but I believe Musk is   
   > shooting much lower), we're under $5M.  Not to bad Hell, at that cost, maybe   
   > I'll splurge and by 4000 square meters.)   
   >   
   > Point being, it's a very solvable problem for a small Mars mission. And as   
   > you grow, you start to look at small nukes or just keep adding in more   
   > panels.   
   >   
   > Not a big problem.   
      
   Nope, not a big problem for a small research station but a huge problem   
   if you are talking about a real colony building things.   
      
   Turning dirt into industrial steel or industrial aluminum to build   
   things takes lots of energy and you are not going to be building   
   log cabins on Mars.   
      
   It takes 20-25 MJ to produce 1 kilogram of iron from iron ore.   
      
   It takes 20-50 MJ to produce 1 kilogram of steel from iron.   
      
   So that is 40-75 MJ/kg of steel from dirt.   
      
   It takes 227-342 MJ to produce 1 kilogram of aluminum from bauxite.   
      
   It takes 7,590-7,755 MJ to produce 1 kilogram of electronic grade silicon.   
      
      
   --   
   Jim Pennino   
      
   --- SoupGate-Win32 v1.05   
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