XPost: sci.astro, sci.physics, sci.space.policy   
   From: fjmccall@gmail.com   
      
   Doc O'Leary   wrote on Mon, 11 Jun   
   2018 03:16:38 -0000 (UTC):   
      
   >For your reference, records indicate that   
   >Jeff Findley  wrote:   
   >>   
   >> High altitude balloon launch is a tad risky and only gains you a bit of   
   >> altitude and zero velocity.  Not worth the complexity and cost, IMHO.   
   >>   
   >   
   >Like I said, it might not *currently* be viable, but as an alternative   
   >technology it brings new sets of trade-offs to the table such that a few   
   >tweaks here and there might make it viable for certain kinds of launches   
   >(e.g., “bulky” items that are hard to make aerodynamically efficient   
   >benefit from starting at the highest possible altitude).   
   >   
      
   And just what such items do we send to space?   
      
   >   
   >>   
   >> BFR/BFS is planned to be "zero waste" from the very beginning.  Fully   
   >> reusable TSTO with "gas and go" like operations.   
   >>   
   >   
   >But that’s not the true “zero waste” I was talking about.  Any resources   
   >that you’re sending up *and* down, along with any fuels you burn to do it   
   >safely, is a waste.  It may be a necessary waste for the current launch   
   >technologies, so it’s good to minimize it, but I still say it’s a good   
   >idea to think about ways to shoot stuff into space that doesn’t involve a   
   >lot of heavy stuff coming back to Earth.   
   >   
      
   Well, let us know if you think of one that doesn't require unobtainium   
   or payloads to take tens of thousands of gravities on launch.   
      
   >   
   >>   
   >> Also don't count out Blue Origin.  They're off to a slow start, but have   
   >> a very reliable funding source in Jeff Bezos ($1 billion a year).   
   >>   
   >   
   >I’m not counting them out, but when the topic is cost/efficiency, the   
   >basic question is still how much energy is being expended to get each   
   >kg into orbit.  So long as the idea is still to send a lot of   
   >supporting (non-fuel) heavy stuff up only to have most of it come back   
   >down, there are wastes that a new technology can come in and improve   
   >upon.   
   >   
      
   We're constrained by the real world.  Magic materials are right out.   
      
   >   
   >>   
   >> Besides, how you going to get those space elevator bits into orbit?   
   >> That's right, conventional (hopefully reusable) launch vehicles.   
   >>   
   >   
   >Hope for bigger things.  I fully believe that, for a society to be   
   >advanced enough to make a space elevator project realistic, it’s value   
   >would be more incremental than revolutionary.  Rockets are the best we   
   >have right now, but we’re stuffed if that’s the best we can do.   
   >   
      
   Just why are we 'stuffed'?  Be specific.   
      
      
   --   
   "Some people get lost in thought because it's such unfamiliar   
    territory."   
                                         --G. Behn   
      
   --- SoupGate-Win32 v1.05   
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