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Re: RE: starship-design: Modular Ship Design

X-From: lparker@cacaphony.net (L. Clayton Parker)

To: KellySt@aol.com, starship-design@lists.uoregon.edu


> -----Original Message-----

> You missed the part of my statement about fuel constraint.  A

> given weight of

> fuel, only has the energy to accelerate the ship to a given delta-V.  It

> doesn't make much difference (speed wise) if it burns all the

> fuel quickly, or

> slowly.  So I figure at 1 g my fusion systems could get you about

> 4-5 months of total thrust.

No I didn't miss it. I wasn't holding the mass of the fuel constant, I was

adding MORE fuel to compensate which is whay I said it required more engine

since adding fuel increases vehicle mass, in order to maintain a constant

acceleration you have to increase thrust, which means you consume more fuel,

etc. but it does work out in the math.

I think I figured out that to get a .4C delta-V you needed something like a
40-100 to 1 fuel ratio. (hence my interest in a no tank fuel).  That only gets
you about 4 months at 1G.  Magnifiing that to get more delta-v would require
stagering fuel quantities!  The engines might need to wiegh an order of mag
more then the unfueled ship!