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Re: Re: starship-design: Plasma Engine

In a message dated 8/31/98 7:30:25 PM, stevev@efn.org wrote:

>KellySt@aol.com writes:
> > In a message dated 8/30/98 11:25:13 AM, lparker@cacaphony.net wrote:
> > >Correction, AIMSTAR is claiming delta v in excess of 900 km/sec, making
> > >almost four times better than the nearest plasma engine.
> > >
> > >For interstellar use, we would need to boost this to at least 90,000
> > >km/sec....
> > >
> > >Lee
> > 
> > The fusion systems I used for the Explorer and Fuel/sail designs had spec
> > of over a million.  Even with that the fuel ratios for the ships were
> > stagering.
> > 
> > Kelly
>The analysis I did a long time ago, which was in terms of
>mass-energy conversion and fuel-to-payload ratios, implied that
>fusion had pretty a exorbitant fuel-to-payload ratio for getting
>to high relativistic speeds (0.8 - 0.9 c), on the order of 10^6:1
>or worse.  To get a fuel-to-payload ratio of less than 10:1 we
>pretty much have to have an antimatter photon rocket.===

True which is why Explorer and Fuel/Sail peak out at about .4 C.

However the 900 KM sec exaust velocity (power source unidentified) would be
far worse.