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Re: New idea Laser launcher/scoop systems

to: tim

> To Kelly,

> >>I assume that with "impulse ratio" you mean "impulse velocity". Than the
> >>answer is yes.
> >>So after "extracting" the energy of the fusion fuel, you could better
> >>the excess mass without accelerating it! (Because if you accelerate it
> >>other mass could be accelerated less)
> >
> >Actually no.  Specific impulse is a term with rockets that tells how much
> >thrust you can get out of a mass of reaction mass or fuel.  (in a normal
> >rocket they are the same.)  For example a pound of hydrogen and oxegen
> >pumped into a shuttle motor generates about 455 pound secounds of thrust.

> (Meaning 1 pound can lift 455 pound?)

Yup, a one second hover.

> >My numbers showed that unless the specific impulse were geting out of the
> >Explorer classes engines is over 2,000,000 we don't get to go.

> I think the specific impulse can be calculated as follows:

> Spec. Impulse = Vexh/a    (non-relativistic)

> Vexh=exhaust velocity
> a=acceleration (10 m/s/s)

> So that would give a Spec.Imp. of about 2.5E6

????  Ah, no I don't think thats correct.

> >So I was
> >woundering is using the fusion fuel directly would make more or less
> >performance mass sence then mixing it in with extra reaction mass, or
> >converting the power to electricity that accelerates a smaller reaction
> >mass in a lineac?

> I'm sorry, I cannot make sense of this sentence, I think 
> you made some writing errors.

The question was, can you get more thrust out of a pound of fusion fuel by
using a reactor to convert it to electricity, and use the electricity to
accelerate a reaction mass (ignoring engineering losses).  Or would
converting the fuel to high speed plasma get you more thrust.

> >Given that the energy in the fusion reactors was all
> >turned into kinetic energy in the exaust plasma, I had assumed using it
> >directly would be most efficent.

> Ofcourse that depends on the possible efficiency and 
> on the exhaust speed of the plasma. Can the latter be 
> regulated by making the outlets smaller or broader?

Efficency?  Efficency of what?

Don't know about using nozzles to accelerate the plasma.