[ExI] SpaceX launch

[Eugen Leitl]

On Thu, Dec 09, 2010 at 04:06:06PM -0800, Adrian Tymes wrote:

> If one can superheat the fuel anyway, one might as well simply superheat it
> directly to plasma and don't bother reacting it.  Unless one includes a
> short-lived fusion reactor as part of the engine, of course.

Your problem is mass. E.g. fusion-enhanced VASIMR would have to
to produce enough additionals thrust to overcome the added
mass.

I personally think that tracked beam propulsion (in the weaker
form, via e.g. a rectenna array feeding a VASIMR unit) will win
by virtue of leaving (most of) the drive at home.
 
> Then again, that's "short-lived" as in "approximately 10 minutes", whereas with
> modern experimental fusion reactors, 10 seconds is considered a very long
> reaction.  (Which makes me wonder how they think they'll get it to commercial
> practicality, which requires sustained power output for hours at least.  I also
> can't help but wonder if engineering for extremely short reactions is part of
> the reason why big fusion reactors have not produced progress
> commensurate with their expense.)

Speculation without knowledge is rarely useful. 
 
> Might anyone know of experiments in long duration plasma containment?

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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