From: zili@home   
      
   Am 29 Dec 2004 22:57:15 -0800 schrieb "Ilpo Lagerstedt":   
      
   >Why not any first stage with LH2/LOX before Delta IV?   
   >Maybe this is a dump question too but I have always wondered that: How   
   >much powerful Saturn 5 would have been LH2/LOX in the first stage?   
      
      The question is NOT how much (much more) powerful a LOX/LH2 driven   
   1st Saturn V stage would have been. The primary questions are: How   
   large would such a stage have become, and: Who would when be able to   
   develop the necessary large engines?   
      
      It WAS a problem to make them in time to reach the great goal of   
   delivering humans to the moon before completion of the 60's decade.   
   When Kennedy's decision to chose THAT national goal was made, the   
   development of the large LOX/Kerosene driven F-1 engine already had   
   reached a status well beyond of a feasability study and Kennedy's   
   advisors used the knowledge of existence of that powerful engine as a   
   feasibility proof, that this goal to reach the moon manned was   
   reachable.   
      
      During the same time the development of LOX/LH2 engines was in a   
   _very_ early stage - the RL-10 engine (used in Centaur and later in   
   Saturn-1, and in use until today in nearly all major US expendable   
   launchers as upper stage engine) just began to become reality, and the   
   J-2 engine used later in Saturn-1B and -V was in a much more embryonic   
   development phase then - without any guarantee, that another scaling   
   up to necessary thrust levels needed for first stage use was feasible   
   at all.   
      
      Today simply the goals have shifted. Even (or maybe especially) the   
   US rocket and engine developers know, that there is a necessity of   
   "clean" launchers in the future - maybe somewhen even the EPA could   
   forbid or strongly restrict the use of solid boosters. But who knows   
   for sure, what the future will bring?   
      
   cu, ZiLi aka HKZL  (Heinrich Zinndorf-Linker)   
   --   
   "Abusus non tollit usum" - Latin: Abuse is no argument against proper use.   
      
   mailto: heinrich@zili.de   http://zili.de   
      
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