XPost: sci.space.science   
   From: henry@spsystems.net   
      
   In article <421ebc7e$0$42486$75868355@news.frii.net>,   
   Jim McCauley  wrote:   
   >I realize that all spacecraft require some degree of radiation hardening...   
      
   LEO satellites don't really need anything beyond error-correcting memory...   
   and in an equatorial orbit, probably not even that.  (Almost all of the   
   bit-flips in memory occur during passage through either the South Atlantic   
   Anomaly or one of the auroral ovals, and an equatorial orbit encounters   
   neither.)   
      
   >...within reasonable limits, what are the altitude ranges that might be   
   >recommended for earth satellites for equatorial orbit?   
      
   The fast answer is that anything between 1000km and geostationary altitude   
   (about 36000km) needs serious radiation hardening and is best avoided.   
   Those boundaries are fuzzy; sensitive applications (e.g. manned) would   
   want to give either a somewhat wider berth, while mildly hardened   
   satellites can intrude on either somewhat.  And the outer region of the   
   belts is quite dynamic.   
   --   
   "Think outside the box -- the box isn't our friend."    |   Henry Spencer   
                                   -- George Herbert       | henry@spsystems.net   
      
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