From: "Zeric.a.pedersonZ"@ZboeingZ.comZ.deZ.to.respond.retro.com   
      
   Andrew Gray wrote:   
   >   
   > Afternoon all.   
   >   
   > The current foremost contender for the X-Prize is, of course, Scaled   
   > Composites - expected to formally announce soon, I believe - which uses   
   > a staged flight method, with horizontal takeoff and landing.   
   >   
   > Other contenders use vertical takeoff and landing single-stage vehicles;   
   > Mr Carmack's group, for example.   
   >   
   > Have any groups studied - I don't recall hearing of any, so I suspect   
   > no-one ran with it - an in-air refuelling system, or would this be   
   > barred by the competition rules?   
   >   
   > (IOW: Spacecraft takes off "light" from a runway, meets tanker at   
   > altitude, fuels up, then makes a ballistic shot with this fuel, gliding   
   > back and landing light)   
   >   
   > I'm not sure why this just wandered into my head, but it would seem to   
   > offer the potential for a system about as efficient as the White   
   > Knight/SS1 concept, with two more steps added (second takeoff,   
   > refuelling) and one removed (in-flight separation).   
   >   
   > (As an aside, would it be possible, in theory, for SS1 to take off from   
   > a runway by itself?)   
   >   
   > I'm travelling at the moment and seem to be having trouble finding a   
   > copy of the rules to examine, but it's quite possible they would   
   > invalidate this due to it involving multiple launches/transfer - the   
   > system as a whole, however, is reusable.   
   >   
   > It is a little more complex, and building two aircraft is beyond the   
   > reach of most groups, but I can't help but wonder what makes it   
   > inefficient that I'm missing    
   >   
      
   For US based teams, FAA reg's would be a problem for this proposal.  The   
   spacecraft would now be operating as a powered aircraft for a significant   
   portion of the flight (SS1 is classified as a glider).  A towed glider   
   configuration is a possibility, with propellant transfer through the   
   tow line, but adds additional complexity for limited benefit.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)