From: daellis94@gmail.com   
      
   On Tuesday, June 12, 2018 at 11:20:23 AM UTC-4, Doc O'Leary wrote:   
   > For your reference, records indicate that    
   > Jeff Findley  wrote:   
   >    
   > > I have an engineering degree.  When developing new things, engineers    
   > > work with what they have today because they've got schedules and    
   > > deadlines to meet.  You're talking about technologies not yet invented.     
   > > That's research, not development.  The two are not the same.   
   >    
   > I never claimed they were.  The topic of the thread is *not* “what can    
   > I build today”, it’s “Towards routine, reusable space launch.”  That    
   > has nothing to do with today’s technology, and nobody has made the    
   > case that continued use of rockets (even reusable ones) can make it    
   > happen.   
   >    
   > > Two different sets of requirements lead to two completely different    
   > > vehicles.  That's how engineering optimization works.   
   >    
   > Indeed.  Which is why I argue that rockets alone are unlikely to be the    
   > only path to space.  And they *definitely* are not the path to deep    
   > space.   
   >    
   > > What you are trying to get me to admit is that eventually, some day,    
   > > there may be something better.  Sure, there might.  Also, monkeys might    
   > > fly out of my butt.   
   >    
   > Really?  You think new technologies are butt-monkeys unlikely?  Then    
   > let’s get you retired, man, because you are *not* allowing your field    
   > to innovate nearly as much as it needs to.   
   >    
   > > I'm not waiting for sci-fi to become reality.  I'm    
   > > working with what I've got today.  Again, that's what engineers do.    
   >    
   > Then you should be looking in engineering newsgroups for that kind of    
   > discussion.  Science is about more than just using your current tools.   
   >    
   > --    
   > "Also . . . I can kill you with my brain."   
   > River Tam, Trash, Firefly   
      
   So, are you talking specifically about chemical-fueled, combustion rockets?    
   If so, then fine, but if you're talking about rockets in a real sense, where   
   "rocket" encompasses combustion-powered as well as various styles of   
   nuclear-powered and/or    
   electrically-powered thrusters, then, yes, rockets are, necessarily, the only   
   way of moving around in space (not counting posited methods of f   
   ster-than-light travel which delve quite far into the realm of the theoretical   
   and the uncertain in terms of    
   physics, which I assume is beyond the scope of the discussion).  Conservation   
   of Momentum sees to that rather conclusively.     
      
   Simply getting to orbit is a somewhat different story, though many approaches   
   are rather limited in possibilities.  For instance, if you have a space   
   station accessible by space elevator, then this station must, necessarily,   
   follow an equatorial orbit.     
   You cannot have a space elevator on a polar orbit.  For those orbits, you   
   either need a rocket to take off from the planet's surface, or to depart from   
   the station at the top of the elevator.     
      
   As far as reusable boost stages are concerned, a large part of the cost of   
   launching an object into orbit is actually in the launch vehicle, itself, not   
   simply the mass of fuel.  The fuel, itself, is cheap compared to the rocket   
   stage, and building an    
   entire booster for each mission is costly.  Only having to build a boost stage   
   ONCE helps cut costs massively.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)