From: Adrian Tymes (wingcat@pacbell.net)
Date: Sun Jan 21 2001 - 10:50:29 MST
Spike Jones wrote:
> > ge (~9000 m/s for standard Low Earth Orbit)
> > Ve = exhaust velocity (~4500 m/s for standard explosive fuel)
> > ...
> > This would probably have to be solid fuels to make the non-consumed
> > part of the engine less than 7 pounds.
>
> Hmmm... Solid fuels dont provide the ~4500 m/s you quoted. The
> 4500 number applies to about the best liquid combination, lox and H2,
> in vacuum. Starting with a 50 pound rocket, I have some *serious*
> doubts we could make it to orbit with 7 pounds. I might believe
> 7 ounces however.
Ok, ok, true. Point is that it's < 100% of the craft's mass - and that
we need *far* better (faster exhaust velocity) fuels than have been
used to date, no? (Lasers - highest exhaust velocity, barring FTL
discoveries - fuelled by matter/antimatter - highest known energy
density - would be nice, but we can settle for more immediately
achievable ones as an intermediate step.)
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