Re: OT: Space ship Message #18 Posted by Jim Horn on 4 Apr 2012, 12:29 p.m., in response to message #1 by Michael Eckstein
The flaw is that the first incremental unit of propellant supplies energy to the ship *and all the rest of the fuel*. Successive units of propellant release the energy contained in themselves including the energy given to them by all that was expended earlier. So yes, propellant used at the end of thrusting provides much more energy than propellant used at liftoff.
For small delta propellants, the linear model does indeed apply as proposed but it breaks down as the quantities become non-insignificant.
Reaction dynamics has all sorts of non-intuitive characteristics. Yes, it really *is* rocket science!
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