From: mstreet@internode.on.net   
      
   Derek Lyons wrote:   
      
   > The real question is...  Why add a *second* propulsion system in the   
   > first place?  If you need a rocket to get from to the scramjet range,   
   > and then a rocket to get from scramjet range to orbital range...  What   
   > is the scramjet adding?   
      
   Potential weight savings from not having to carry oxidiser along means   
   smaller booster stage and/or larger payload for given booster stage size.   
      
   But will that outweigh the greater weight of the scramjet engine?   
      
   No-one knows for sure yet.  The University of Queensland scramjet research   
   program is quite explicitly looking at using them as the second stage for   
   launchers as its primary mission.   
      
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   Malcolm Street   
   Canberra, Australia   
   The nation's capital   
      
   --- SoupGate-Win32 v1.05   
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