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In lugnet.off-topic.geek, Dave Schuler wrote:
> In lugnet.off-topic.geek, Larry Pieniazek wrote:
> > In lugnet.off-topic.geek, Dan Boger wrote:
> > > On Sat, Jan 17, 2004 at 04:28:44AM +0000, Larry Pieniazek wrote:
> > > > Um, no I don't. And stop resetting the FUT back to geek.
> > >
> > > Why? I think this discussion is very appropriate to .geek, except for
> > > the parts where you are starting a debate. Any reason we can't talk
> > > about NASA here?
> >
> > "lugnet.off-topic.geek (group):
> > Geeking and geek toys (computing, games, peripherals, hacking,
> > science, etc.): discussions of a generally (but not necessarily
> > always) positive and serious or helpful nature."
> >
> > You may not agree, but it seems pretty clear cut to me. Now, not every point of
> > disagreement is necessarily debate fodder... if you were to focus on the merits
> > of Hohman transfer orbits versus continuous boost, then sure, that'd be .geek.
> > But that's not the case here.
> >
> > The question asked is framed in an economic context, not purely a technical one.
> > As soon as someone says "wouldn't X be monstrously expensive", that, in my view,
> > moves the topic right out of .geek and into .debate
>
> If I read the original post correctly, the question was of fuel efficiency and
> the physical implications of a Moon-based versus an Earth-based launch toward
> Mars and beyond. Naturally this entails the cost of development, because fuel
> costs money, but the primary question is about physics (i.e., geeking).
>
> My subsequent question about the monstrous expense of building on the Moon is
> likewise largely grounded in the physical realities of such a construction
> project. Building off-world in that fashion *would* be very expensive, whether
> Burt Rutan is at the helm or not.
Well, there's expensive and there's *VERY expensive*, in terms of dollars per
unit of work on task. Asserting that NASA falls into the latter camp (as I do)
is debate fodder, so if you want to stay out of .debate, as you seem to, we
won't get into that part of it, much.
But to the question of whether an industrial base on the Moon makes sense to a
Mars mission, I think the question fundamentally turns on what is it you want to
do? If you want a one time stunt, send someone to Mars and get them back and do
nothing further (ala what Apollo did for the Moon, regrettably), then yes,
taking the long term view of what is the most efficient way to do it is the
wrong question, and the answer is do an EOR mission with no Moon basing. For a
single mission it's cheaper because you're not boosting industrial componentry
(however small and bootstrappable (1)).
But in the long term, anything boosted out of the earth's atmosphere complicated
gravity well is the thing thats' "horrifically expensive" on a per pound basis,
no matter what you do to reduce costs, compared to boosting things you obtained
locally from a smaller well with no atmosphere to complicate matters.
Further, because of mass fraction considerations and material efficiency
considerations given our current materials tech (fuel tanks are dead weight and
can be made only so light for a given tensile strength material, etc), the more
delta V you want to generate, the worse the problem becomes. You end up burning
thousands of pounds of fuel to put one pound in Hohman transfer orbit.
So if your long term goal is permanent manned presence because you want
permanent exploitation, you want to get as much mass elsewhere than earth as you
can. And you want to reduce your dependence on low Isp chemical rockets as much
as you can. Hence a moon industrial base is the logical way to do it. Either
that or comet/asteroid mining, but that's rather a bit harder I think at our
current state of tool development. (that can be done with mostly ion drive if
you're clever enough)
Transport economics can be distortive if you look only at them, though. I see
EOR missions as analogous to the sending of laundry to China by boat from
California that was (possibly apocryphally) practiced in the 19th century
because importing laundry workers and developing laundry facilities was viewed
as less convenient/cost effective than shipping the laundry.
Again, define what you want to do, and the answer is obvious.
Mars as a stunt? Moon is a distraction.
Mars as a permanent inhabited economically viable exploitation? Moon or asteroid
is a necessary intermediate step.
I'll reassert without proof my assertion that given to the right person(2) with
the right incentives, 12B is plenty of seed money to get a moonbase and a
permanent manned presence on both the Moon and Mars. It won't happen overnight
and there will be a lot of exploitation of resources and money made along the
way but it's plenty of seed capital. Given the right person.
I'll also assert we've done enough stunts and it's time to move from exploration
to exploitation.
++Lar (set the FUT however you like, I give up)
1 - while I share your distaste for jargon laden prose, I submit that bootstrap
is precisely the right word to use here, and my only regret is that it's been
overused elsewhere/elsewhence, not that I used it here.
2 - defined as a person that has already won the X prize and turned a profit
doing it, and therefore in possesion of a low cost fully reusable LEO launch
capability not subject to government featherbedding. That's not Burt. At least
not yet it isn't... ;-)
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Message has 1 Reply:
 | | Re: We're here to go
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| (...) I don't have any problem with pursuing that end of the discussion, but I wasn't trying to kick of a debate with my original question. If it winds up there, though, I say groovy! I enjoyed that previous debate re: cost-value of space (...) (20 years ago, 20-Jan-04, to lugnet.off-topic.geek, lugnet.off-topic.debate)
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Message is in Reply To:
| | Re: We're here to go
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| (...) If I read the original post correctly, the question was of fuel efficiency and the physical implications of a Moon-based versus an Earth-based launch toward Mars and beyond. Naturally this entails the cost of development, because fuel costs (...) (20 years ago, 20-Jan-04, to lugnet.off-topic.geek, lugnet.off-topic.debate)
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