XPost: rec.arts.sf.written, sci.space.policy, sci.physics   
   From: fjmccall@gmail.com   
      
   Thomas Koenig  wrote on Thu, 7 Jun 2018   
   16:42:38 -0000 (UTC):   
      
   >Jeff Findley  schrieb:   
   >> In article ,   
   >> tkoenig@netcologne.de says...   
   >>>   
   >>> 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.   
   >>   
   >> That's a solved problem.   
   >   
   >It is a problem which can be solved, at a possible cost to   
   >performance (added mass).   
   >   
   >I doubt it has been solved for all of the "many stages" you   
   >mentioned.  That would have been counterproductive to the   
   >primary mission, and would probably have been regarded as   
   >an error.   
   >   
   >Can you elaborate which stages this was solved for, how, why,   
   >and where you got the info from?   
   >   
      
   Stress is higher on the first stage structure when there is a big mass   
   sitting on top of it than when there is not.  If it can stand the   
   stress of launch with a second stage and payload, it can stand the   
   stress of launch without them.   
      
      
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   "Ignorance is preferable to error, and he is less remote from the   
    truth who believes nothing than he who believes what is wrong."   
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