XPost: rec.arts.sf.written, sci.space.policy, sci.physics   
   From: tkoenig@netcologne.de   
      
   Jeff Findley  schrieb:   
      
   > We've had this debate a long, long time ago in the sci.space newsgroups.   
   > The fact is that there are many stages which are theoretically capable   
   > of performing SSTO with minimal payload.  No one has ever done it   
   > because the cost to get that payload into orbit is typically higher than   
   > it would be if you just used a smaller TSTO (or higher number of   
   > stages).  In other words, it just makes no sense to fly a disposable   
   > SSTO.   
      
   There are also other considerations to take into account.   
      
   One of them is mechanical. A first stage flying with a much smaller   
   payload than the current second stage + actual payload would   
   have much lower mass towards the end of the burn, resulting in   
   higher acceleration and higher mechanical stress.  Buckling could   
   be something that needed to to be guarded against, as could be   
   outright failure due to compression stress.   
      
   Possible solutions if it turns out to be a problem:   
      
   Turn down the engine thrust (How far is that possible? Can the   
   engines even do that? What will it do to the specific impulse?)   
   or switch off individual engines (what happens if you swith off   
   one half a second later than the others?).   
      
   Strenghten the strucutre. This would add mass, and it would not   
   be the same first stage anymore.   
      
   --- SoupGate-Win32 v1.05   
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