But time was already money the first time. How do the ratios change
to favor the moon?

Of course, once the load of unprocessed or minimally-processed
asteroid material is in HEO, the moon has no time advantage over
that material. Replenishing that material seems likely to be a
small part of the total costs. So the time-is-money factor seems as
though it would have to remain small.

I think the moon gains an advantage when sheer quantity is needed.
The moon has a huge startup cost and high ongoing costs to maintain
a moon base even if it does nothing but sit there, but then it can
supply a practically unlimited amount of material for moderate
additional costs.

--- In spacesettlers@yahoogroups.com, "Combs, Mike"
> From: spacesettlers@yahoogroups.com
> [mailto:spacesettlers@yahoogroups.com] On Behalf Of Dan Wylie-Sears
>
> > Asteroidal resources in HEO certainly do make it easier
> > to set up a moon base. But don't they equally make it
> > easier to go after more NEOs? And if it was easier to
> > go after NEOs first, why wouldn't it stay that way until
> > the targets of easy opportunity are depleted or until the
> > sheer amount of mass demanded exceeds what's available in
> > low-delta-vee orbits with convenient lauch windows?
>
> As I said before, perhaps for no other reason than that time is
money.
> The moon will always have the advantage of short transit times for
raw

I know I've asked this before, but that was a few years back, so I'm
going to ask again. Back then, the answer seemed to be "nobody
knows," and that may well be the answer today. But then again perhaps
not.

Is it possible that astroidal material is *already at* L4 or L5? Not
any really big asteroids, of course. They would've been seen
already. But the kidney-bean orbits are pretty big, and I could well
imagine a few thousand 10 metre or less chunks of stuff (sooty, carbon-
rich, non-reflective stuff) trapped there, just waiting for us to put
it to use. If it is there, such material would have all the "it's so
close!" advantages of the Moon, and all the "variety of material"
and "low delta-V" advantages of the asteroids.

Disadvantages could be that it may not be a whole lot of material
overall, and that it could be a debris hazard. In this second case,
though, it would be a problem that would have to be dealt with in any
case (at least in any case in which L-5 or L-4 was going to be used
for much of anything).

Excellent post.

Honestly, I would be surprised if there's nothing at L5.

Seems there has to be something if only a small rock or two.

Would be interesting to find out.

--- In spacesettlers@yahoogroups.com, "Xenophile"

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Xenophile

> Is it possible that astroidal material is *already at* L4 or L5?

I do happen to know that SSI gave some money to an astronomy student who
for his thesis wanted to do telescopic observations of L4 and L5 for
trapped material. I never heard anything to the effect that he didn't
get to make his observations, and I'm sure if he'd discovered anything
there would have been lots of discussion about it.

An open question would be at what level of detection would his
observations have operated at. In other words, even if we can rule out
asteroidal bodies a city block in size, can we not rule out bodies the
size of apartment buildings? Even bodies the size of houses might be
useful from our standpoint.

Regards,

Mike Combs

I recall reading in the news a few years ago reports that space junk
from the Appollo flights had been seen in that area.

--- In spacesettlers@yahoogroups.com, "Combs, Mike"
> From: spacesettlers@yahoogroups.com
> [mailto:spacesettlers@yahoogroups.com] On Behalf Of Xenophile
>
> > Is it possible that astroidal material is *already at* L4 or L5?
>
> I do happen to know that SSI gave some money to an astronomy
student who
> for his thesis wanted to do telescopic observations of L4 and L5 for
> trapped material. I never heard anything to the effect that he
didn't
> get to make his observations, and I'm sure if he'd discovered
anything
> there would have been lots of discussion about it.
>
> An open question would be at what level of detection would his
> observations have operated at. In other words, even if we can rule
out
> asteroidal bodies a city block in size, can we not rule out bodies
the
> size of apartment buildings? Even bodies the size of houses might
be

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of terrierkeeper

> I recall reading in the news a few years ago reports that
> space junk from the Appollo flights had been seen in that area.

No, what you're thinking of is that for a while (I don't think it's any
longer the case) there was a extremely tiny "asteroid" in a high,
elliptical orbit about the Earth. It had been speculated that one of
the Apollo upper stages had gone into its own independent solar orbit
inside the orbit of the Earth. This had the effect of the upper stage
eventually "lapping" the Earth after all these decades. It was thought
that the upper stage had come near the Sun-Earth L-1 point (as distinct
from the Earth-Moon L-4 or L-5 points), and had slipped through that
point to take up an elliptical orbit about the Earth. I think that's
the source of the mental link you have between this event and Lagrange
points.

A spectroscopic analysis detected titanium, and given that titanium
dioxide is the pigment in white paint, this was seen as lending credence
to the theory that it was old Apollo hardware rather than a natural
body.

Regards,

Mike Combs

--- In spacesettlers, "terrierkeeper" wrote:

> I recall reading in the news a few years ago reports that space
> junk from the Appollo flights had been seen in that area.

Even this could be useful, in a recycling program that saves us
launching a few hundred tons. And Apollo stuff is nice and shiny.
Dull black stuff could still be there. However...

> --- In spacesettlers, "Combs, Mike" wrote:

>> I do happen to know that SSI gave some money to an astronomy
>> student who for his thesis wanted to do telescopic observations of
>> L4 and L5 for trapped material. I never heard anything to the
>> effect that he didn't get to make his observations, and I'm sure
>> if he'd discovered anything there would have been lots of
>> discussion about it.

This is the thing that gives me pause whenever I think of bringing
this up: the near-certainty that somebody else has thought of it, and
indeed tried it. I, too suspect that if he'd found anything, we
would all know it.

>> An open question would be at what level of detection would his
>> observations have operated at. In other words, even if we can
>> rule out asteroidal bodies a city block in size, can we not rule
>> out bodies the size of apartment buildings? Even bodies the size
>> of houses might be useful from our standpoint.

Indeed they might! Like Cygonaut, I find it hard to believe that
there is *nothing* there. If Apollo stuff can wind up there, why not
rocks? And that Apollo stuff, might it not be house-sized? Heck,
even port-a-potty-sized chunks of metals and carbon and silicates and
maybe hydrates of some sort would be wonderful, especially if there
are a LOT of port-a-potties.