From: trident5955@gmail.com   
      
   Recently I learned that solid Nuclear thermal rockets need not run on hydrogen   
   with its meek density. They can run on Water or ammonia. Using water as a   
   propellant slashes expected specific impulse by half, from 8 to 4 km/s. But   
   stilll this rocket has    
   greater Isp than most chemical rockets with exception of LOx/Lh2 systems,   
   which also  suffer from being robust, like hydrogen NTR.   
      
   My questions is: Why nobody (to my knowledge at least) never explored the   
   possibility of water NTR. I know that DUMBO NTR in rocket's first stage may   
   give you creeps, but the air-beathing NTR with nuclear firs stage was at least   
   theoretically    
   investigated whereas water NTR was not? Why is that?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)