Chris Adams wrote:   
   > Once upon a time, Jeffrey Kaplan   said:   
   >> If something goes wrong, you're screwed either way.  Heat shields can   
   >> fail, parachutes can fail in several ways, etc.   
   >    
   > Wings give you a much larger area of failure.  You are also having to   
   > launch a lot more structure, which is wasted mass to orbit.   
   >    
   >>> We are a long way from any technology that would allow a vehicle to take   
   >>> off like an airplane and make it to space.   
   >> That is merely a question of engineering, not science.  We HAVE the   
   >> technology, just not the will due to cost.  I'd bet that any of us here   
   >> could sketch out the basic design criteria of such a craft and with the   
   >> proper engineering to make it real, it would work.  It might cost a   
   >> couple billion dollars at first and be the size of a 747 or C5, but it   
   >> would work.   
   >    
   > Go ahead, I'll wait.  How is it looking?   
   >    
   > We really don't have the technology to do that.  We really can't make   
   > the vehicle much lighter (and still be able to carry anything) due to   
   > the limits of materials.  For example, the X-33 test vehicle was going   
   > to use carbon-fiber composite fuel tanks, but they didn't work out.   
   > Liquid hydrogen is a hard thing to hold; it blew the sides off of the   
   > tank in a test.  The SSME (Space Shuttle Main Engine) is already the   
   > highest performing rocket engine ever built, and it can't come anywhere   
   > near handling a horizontal takeoff.   
      
      :)  If it can perform for vertical T/O, how much easier would it be for    
   horizontal. You just need to attach a giant wing. :)   
      Seriously, the attraction of a winged takeoff and acceleration is the    
   incredibly better mass efficiency of atmosphere burning engines, because you    
   don't have to accelerate the oxidizer. And it is the more massive of the two -    
   when burning hydrogen, the oxygen component is 8 times as heavy. If winged    
   takeoff to orbit is ever achieved, it would have to be a piggyback system,   
   where    
   the base is a ginormous flying wing carrier that takes off and accelerates to    
   supersonic as high in the stratosphere as it can, where the Scram jet engines   
   of    
   the reentry vehicle can take over and accelerate it as much as they can while    
   still burning atmosphere oxygen. The final push must be from a more   
   traditional    
   rocket last stage (could be attached to the rear, if the Scram exhaust is on   
   the    
   sides, or could be detachable boosters).   
      As far as I know, there are still no reliable scramjets for the second   
   stage    
   segment.   
      
      
   > Reusable didn't work out that well either.  The stresses on the vehicle   
   > were pushing the limits, so a lot of inspection and refurbishment was   
   > required between every flight (the SSMEs were essentially rebuilt every   
   > time).   
      
      Isn't that because the shuttle was too big? If it was only for people    
   transport, it could be made much smaller and sturdier.   
      
   --    
   No, no, you can't e-mail me with the nono.   
   --- SBBSecho 2.12-Win32   
    * Origin: Time Warp of the Future BBS - Home of League 10 (1:14/400)