From: root@mauve.demon.co.uk   
      
   In article <3a1d1813.0406210740.467d250d@posting.google.com> you wrote:   
      
   > Now, correct me if I'm wrong, but didn't the commercial SpaceShipOne   
   > reach the very edge of the atmosphere? Doesn't it also need the   
   > observe the same careful considerations for reentry?   
   > If not, why? In simple "Physics for English Majors" language. =)   
      
   Basically, as it's going much, much slower.   
   Craft reentering from low-earth orbit come in at around mach 30.   
   The SS1 reenters at mach 3 (?).   
   Heating is more or less proportional to the cube of speed, so the   
   heating will be around a thousandth of that coming in from orbit.   
   The RS-71 flew at mach 3, and was fine with just a titanium skin.   
   If you tried to put a titanium skin on a craft coming in at orbital   
   velocities, you get little more than a bright shower of sparks   
   as it atomises.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)