[extropy-chat] FWD [forteana] Re: Are dwarfs better forlongduration spaceflight?]

[Adrian Tymes]

--- Eugen Leitl <eugen at leitl.org> wrote:
> Nuclear power in space is a very hard sell politically.

Not as hard as selling a dwarf-only mission.

> The technology doesn't exist yet in the first place, and needs
> to be developed and tested.

Development and testing are needed, but it does exist.  Then again,
dev & test are needed for this mission anyway: there does not presently
exist a rocket capable of sustaining one human life, even a dwarf's,
while going to Mars and returning under its own power.

> Nuke-powered ion/plasma drive would be probably an optimal
> combination even for manned flight. It would be easier to
> assemble and fuel up the craft in orbit, and go chemical
> all the way, with a minimum-mass crew module (with robots
> sent ahead preparing the habitat, and the fuel still) by
> remote control.

Easier in some respects, harder in others.  The more money and
resources a project requires, the harder it inherently is: you have to
spend effort to gain said money and resources.  I suspect this may be
part of what you overlooked.

> > The scaling factor of different propulsion systems trumps the
> > difference in crew dimensions.  For example: calculate how much
> rocket
> > you would need to make the trip in a few months (one way) on
> hydrazine.
> 
> What is wrong with using cryogenic fuel, e.g. methane/oxygen?

*shrugs*  Nothing, for the sake of this discussion.  Just pick a fuel
so you can work the numbers.  Nuclear/ion propulsion beats any chemcal
fuel by a sufficiently large margin that focusing the finite dev/test
resources on that, rather than spending effort on minimizing the crew
(and taking the resulting benefits), will achieve optimal payoffs.
(Remember, any mission always has a finite budget.  Some potentially
marginally beneficial ideas almost always have to tossed to the side in
order to focus on the best paying off ideas.  The marginal and very
mission-specific payoffs from the dwarf proposal would seem to be an
example of this.)