From: henry@spsystems.net   
      
   In article <40078965.308702091@news.eircom.net>,   
   Russell Wallace  wrote:   
   >>...The real problem is the cold, that's going to   
   >>kill the rover stone dead with absolute certainty in a few months.   
   >   
   >Why will cold kill it? I know excessive heat is bad for electronic   
   >components, but I thought microchips if anything worked better at   
   >lower temperatures?   
      
   The problem is not so much cold in itself, but the huge temperature swings   
   during the day-night cycle.  The total swing from daily high to daily low   
   there is typically 80degC -- like going from a hot day in Mojave to a cold   
   winter's night in Alberta.   
      
   The electronics won't see the full extent of that right away, because they   
   have electrical heat during the night... but as Mars moves farther from   
   the Sun, and Sun angles at the landing site deterioriate with seasonal   
   change, and the rover's battery gradually wears out, less and less energy   
   will be available at night.  And so the electronics will see increasing   
   temperature swings, and increasing thermal-contraction stresses between   
   different materials.  Fairly soon, things will start to crack.   
      
   Mars Pathfinder died shortly after its battery gave out.   
   --   
   MOST launched 30 June; science observations running     |   Henry Spencer   
   since Oct; first surprises seen; papers pending.        | henry@spsystems.net   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)