From: henry@spsystems.net   
      
   In article ,   
   ANTIcarrot  wrote:   
   >How much energy can mirros focus onto a solar panel before it begins to   
   >melt?   
      
   A more fundamental problem than melting is that solar-cell efficiency   
   drops off as the cells get hot, although this is less important for   
   advanced cell materials than it was for silicon.   
      
   Modest amounts of concentration are workable -- Deep Space 1 used lens   
   concentrators -- and my (dim) recollection is that concentration ratios of   
   up to 100:1 have been explored in studies.  Still, there are limits; even   
   the best cells die at hundreds, not thousands, of degrees.   
      
   >...Could large light-weight mirrors and   
   >small solar arrays replace the traditional massive structures of the NASA   
   >1980s design study?   
      
   The tradeoffs are complex, particularly if you are thinking about using   
   extraterrestrial materials (in which case you can forget about the exotic   
   advanced cell materials -- you're pretty much restricted to silicon, which   
   is not very heat-tolerant).   
      
   Even at 100:1, though, the actual arrays are in not "small" in any   
   realistic sense of the word.   
   --   
   "Think outside the box -- the box isn't our friend."    |   Henry Spencer   
                                   -- George Herbert       | henry@spsystems.net   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)