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*To*: stevev@efn.org*Subject*: Re: starship-design: Re: FTL travel*From*: STAR1SHIP@aol.com*Date*: Sun, 26 Mar 2000 14:50:19 EST*CC*: starship-design@lists.uoregon.edu*Reply-To*: STAR1SHIP@aol.com*Sender*: owner-starship-design@lists.uoregon.edu

In a message dated 3/20/00 8:54:15 PM Pacific Standard Time, stevev@efn.org writes: > > The ship carries the fuel. Either both the ship and the fuel get more > massive with velocity or both the ship and the fuel stay the same mass. > Are you claiming that the fuel gets more massive but the ship that > carries it stays the same? Either way the fuel can only provide so much > acceleration, and that little fission fuel can't propel a heavier > payload to relativistic velocities. > > Hi Steve, Taking for example the general equation MVof exhaust=MVof payload. to accelerate a given payload mass of 5 tons twice light speed requires I accelerate 100 tons of exhaust to 1/10 light speed (at 1 g acceleration). Using the equation E(kinetic)=1/2 MV we get the energy required. using the equation E=Mc^2 we get the mass that needs to be converted providing the energy. >From the laws of conservation momentum(P) we have the equation P=MV as momentum is required by universal law to be conserved. P of exhaust= P of payload. this shown in the equation MV of exhaust=P=MV of payload. it is proven mathematically with an identity proof (the strongest of math proofs)stating if a=b and b=c then a=c or (a=b=c). Machines like partical accelerators that use the general instantaneous acceleration equation of E'=1/2 MV gamma, reguire the Energy relativistic equation to be used for the energy is delivered intantaneously (small increment of time)from the relativistic(observer or rest) frame instead of the frame of moving(inertial) object and is therefore limited to below light speed relativistic so that momentum is conserved. The equation commonly leading to a erroneous velocity real calculation of like .3 or .8c was derived by Einstein and clearly labeled Velocity Rel.(for relativistic velocity) in the margin. Subsequent typists saw the label out there by itself and not knowing what it meant dropped the label and kept the equation. Mathematicians often tire of writing the full variable parameter of velocity relativistic in freehand so use V (subscript rel.) or better yet just v as v=Velocity Relativistic with the understanding the equations are under the defining label and the relativistic(observer) frame and distinguishable from velocity real of the ship frame of reference also designated as Velocity Real by label. Just remember that regardless of what an observer on earth calculates as relativistic regarding the moving ship, aboard the ship all remains normal (real) as a basic postulate of relativity. Placing both sets of equations on a page can be confusing as some use prime( ' ) for relativistic and drop the subscript real just using the small case variable letter without prime and the labels and variable definitions are required to be placed at the top any calculations to prevent confusion. Another common mistake with rocket equations when I give students a problem with constants to solve containing 1 g some invariably look through the unified field of equations I also give and select the first one with 1 g in it and attempt to solve with ISP(specific impulse calculation) and when the equation v=gt is the one to be used. ISP numbers stamped on model rocket engines are determined by measurements of actually firings of chemical rockets so that a given payload mass attached can be reliably calculated with the special equation to give an accurate velocity predictions in a uniform gravitational field of one g (near earth's surface). ISP numbers and predictions of what they would be are only guess work (usually poor guesses at that) for atomic engines as the measurement database has yet to be built. To get accurate velocity calculations the original general rocket equations are to used. Regards, Tom

**Follow-Ups**:**Re: starship-design: Re: FTL travel***From:*Steve VanDevender <stevev@efn.org>

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