From: jeff.findley@ugs.nojunk.com   
      
   "Tom Kalvelage"  wrote in message   
   news:aa15a454.0408311955.6f3a981e@posting.google.com...   
   > For simplicity, both stages are VTVL.  The only thing close to new   
   > engineering is jettisoning or retracting the second stage exhaust   
   > bells and closing the holes in the heatshield for reentry, then   
   > opening the holes for the engines to fire through on landing.   
      
   It's been suggested that instead of doing anything fancy like that, you   
   could just run some LH2 through the engines during re-entry, or even run the   
   engines at "idle" during re-entry.  Either of these would greatly reduce the   
   heat load on the engines.   
      
   > The DC-X, Armadillo Aerospace, and the Japanese RVT vehicle have   
   > demonstrated VTVL.  The Shuttle has holes in it's heatshield that it   
   > closes and opens (landing gear).   
      
   True, but you've got to be very careful about this.  Failure of any of the   
   doors to close would result in loss of vehicle if re-entry is attempted.   
   Furthermore, failure of the doors to open (on landing gear and/or braking   
   rockets) would also result in a crash upon landing.   
      
   > Apollo had heatshields.  Soyuz does   
   > a good job on reentry.  There are lots of engines available.  If the   
   > stages were only built for 10-20 reuses, we could keep fielding   
   > improved versions, learning about SSTO and BDB in the process.  It   
   > would likely help the US launch industry regain market share.  Many   
   > rocket scientists have proposed some or all of this before.   
   >   
   > So why is there no interest?  Is the concept goofed up in some   
   > non-obvious way?  Am I missing something?   
      
   There certainly is interest (as evidenced by start-ups which are pursuing   
   similar designs), but NASA is another story.  If they go ahead with plans to   
   return to the moon, that leaves little money to develop new launch vehicles   
   like you're talking about.  They'll be spending the money on the CEV and on   
   the missions this modular spacecraft flies.   
      
   Jeff   
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