From: henry@spsystems.net   
      
   In article <4ofSc.425593$Gx4.392265@bgtnsc04-news.ops.worldnet.att.net>,   
   Lizerd <1@2.com.retro.com> wrote:   
   >Early on in the space program, the space capsule used brute force re-entry.   
   >IE: it slammed into the upper atmosphere at high speed to slow down for   
   >return.   
      
   That is the only method anyone has ever used for reentry, from that day   
   to this:  atmospheric braking.  The details have gotten fancier (in most   
   cases), but the basic scheme of things has not.   
      
   >The space shuttle is a lifting body.   
   >Why can't it fly back???   
      
   It does.  The Apollo and Gemini capsules were lifting bodies too, by the   
   way (and so is Soyuz).  They all use aerodynamic lift to stretch their   
   reentries out as much as they can.  But there are severe fundamental   
   limits to what can be done.  Even pushing it as far as the shuttle orbiter   
   does incurs serious penalties, notably a thermal protection system which   
   is complicated and rather fragile compared to the simple and robust   
   heatshields the capsules used.   
      
   >If the shuttle hit the atmosphere slower, use aero braking and descend at   
   >a shallower angle, the shuttle could return at a slower decent rate, and not   
   >be subjected to the high temptures.   
      
   The longer, slower reentry the shuttle uses makes its thermal problems   
   *worse*, not better.  The prolonged baking is actually rather harder to   
   handle than a quick blowtorching.   
      
   In any case, this isn't a question of the shuttle being deliberately   
   operated in some stupid, suboptimal way.  It *already* uses aerodynamic   
   lift as much as it can without melting something off.   
   --   
   "Think outside the box -- the box isn't our friend."    |   Henry Spencer   
                                   -- George Herbert       | henry@spsystems.net   
      
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