The Moon vs. Mars/Asteroids

> I agree all simple models are oversimplifications, which I
thought I
> acknowledged adequately. But to compare, 104 one week missions
returning
> 20% profit per mission if reinvested still gives $ 172 million
profit for $
> 1 invested, while one mission returning $ 256 (or any other
reasonable
> number) for $ 1 invested in 104 weeks gives $ 255 (or what-ever)
profit.
> Which would you like to retire on?

I didn't touch on this in my earlier response. Your numbers don't
make sense. Let's take your assumptions and rerun the numbers. Lunar
payback is %20 for every dollar invested($0.20). Asteroidal payback
is 100% for every dollar invested ($1). This has to be wrong because
I have already shown that an asteroidal mission can return 256 times
the material.
There is no reason to suppose that the lunar and asteroidal missions
wouldn't mine and return the same marketable materials (platinum
groups metals for instance). If a lunar mission was able to return
1kg of marketable material, an asteroidal mission would return 256kg
of the same material.
I just looked up futures on platinum. Quotes range from $428/oz down
to $408/oz. Lets call it $400 for simplicities sake. 35.2736 ounces
in 1 kg. $400 x 35.2736 = $14,109.44 value per kg. Lunar mission
would return $14,109.44 x 104 = $1,467,381.76 Asteroidal returns,
$14,109.44 x 256 = $3,612,015.64

$1.4m
$3.6m

Now this is very simplistic, there are a lot of other complications.
Compounded interest on lunar's earlier cash returns, debt serviceing
of asteroidal mission (significant), added costs for 256 lunar probe
refueling launches (quite significant), ect. But this is the
simplistic ballpark we're playing in.

> Asteroids also have nights, which occupy half of the time.
Towers can be

Asteroid nights last only hours, batteries can pick up the slack.
Lunar nights last days, batteries would be too massive.

> set up with solar collectors at lunar (or asteroid) poles should
one chose

Distance to asteroid poles, at most it's 17 kilometers on Eros,
distance to lunar poles, 100's of kilometers (up to 868km). Big
complication.

> to use solar power. Very low asteroid gravity adds some problems,
for
> example making it take a long time, hours to months in some cases,
for
> asteroid dust to settle, which could block sun and fowl lots of
equipment.

Actually, it wouldn't take much to cause the dust to reach escape
velocity. I seriously doubt that there would be dense enough dust
clouds to hamper solar collection. With such a low gravity well,
small bursts of gas emitted by the mining probe would clear the air
(so to speak).
Dust will be a factor in fowling equpment, more so on an asteroid
that on luna, I agree with you there. I just doubt that it would be a
significant factor that smart engineering wouldn't solve.

king_rodent