From: henry@spsystems.net   
      
   In article ,   
   James Graves  wrote:   
   >...any type of air-breathing for orbital launch is a waste of time   
   >and money.  Turbojets, scramjets, whatever.  It just makes getting into   
   >orbit harder, not easier.   
   >The only exception to this is an aircraft carrier 1st stage...   
      
   I'm inclined to say that the jury is still out on LACE and its relatives   
   (such as Alan Bond's concepts) and on things like the original Roton,   
   which airbreathe a little bit at the start of a largely rocket-powered   
   ascent.  The idea is plausible; what remains unproven is that it's any   
   better than a pure rocket.  I wouldn't build one myself, but wouldn't   
   exclude the possibility of success that way.   
      
   >While this is drifting off-topic for this newsgroup, can someone explain   
   >to me why so many in the aero/astro field still think hypersonics for   
   >orbital launch are a good idea?   
      
   To some extent this is a lingering echo of the idea that spaceships are,   
   or *should be*, just especially high-performance aircraft.  There has   
   never been any very strong justification for this belief, but it remains   
   an article of faith for many from the "aero" side of aerospace.   
      
   And to some extent, it's pure public-relations hype, the result of the   
   hypersonics people -- who have been largely rejected by the aero side of   
   the house -- trying to find funding from the space side (which has long   
   been the rich side of the family).   
      
   >And are hypersonics a good idea for anything at all?   
      
   For high-speed cruise within the atmosphere -- assuming you have some   
   urgent reason to want to do that -- they look promising.  But they have   
   nothing much to do with spaceflight.   
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