From: ansible@typhoon.xnet.com   
      
   Henry Spencer  wrote:   
      
   >Catching up on some unread journals, I note that the March/April 2003   
   >issue of JBIS has a very interesting paper:  "A comparison of propulsion   
   >concepts for SSTO reusable launchers", by Richard Varvill and Alan Bond.   
   >While the authors have a mild case of hydrogen religion -- non-hydrogen   
   >rockets are never mentioned -- and they obviously have their own axe to   
   >grind, they generally give a good overview of the alternatives, including   
   >why scramjets are such a lousy idea for space launch.   
      
   This is all my opinion, of course...   
      
   After reading this newsgroup for a while, I have come to the conclusion   
   that 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.  There are   
   some advantages to high altitude launch (less altitude compensation   
   needed for your rocket nozzle, for example), and it can give you a lot   
   of flexibility with launch site location.  But that's the only   
   exception in my view.   
      
   I just can't understand why so much time and research dollars are being   
   spent on hypersonic research.  If you want to get into orbit, you want   
   to get _out_ of the atmosphere as soon as possible.  It is completely   
   counter-intuitive to try and gain lots of velocity while still inside   
   the atmosphere, where you are subject to drag (inefficiency) and heating   
   (exotic materials and/or cooling systems needed).   
      
   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?   
      
   And are hypersonics a good idea for anything at all?   
      
   James Graves   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)