From: ansible@typhoon.xnet.com   
      
   William Malverson  wrote:   
      
   >In hundreds of manned space flights, the TPS has only catastrophically   
   >failed once, [...]   
      
   Ths SST TPS had _almost_ catastrophically failed at least once previously.   
      
   There were a burn-through near one of the elevons.  Luckily for the crew   
   of that mission, they made it back safely.   
      
   But had the burn-through been a meter this way or that way, it would   
   have damaged some cables, or the elevon hinge, or...   
      
   And there had been previous concerns with the tiles in general, and with   
   ice falling of the ET.   
      
   > [...] so I'm going to assume that upgrading SS1's hull to handle   
   >reentry, while not trivial, would not require anything terribly difficult.   
      
   Well, it isn't going to be easy.  Still the most straight-forward type   
   of TPS is a non-reusable ablative heatshield like on Soyuz, Apollo, etc.   
      
   With that system, it is easy enough to put in a nice, generous design   
   margin, which guarantees you will get down to the ground in one piece.   
      
   But obviously, that's not going to work with a glider like SS1.   
      
   Anything else is difficult and less proven.   
      
   All, IMHO, of course.   
      
   James Graves   
      
   --- SoupGate-Win32 v1.05   
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