Diversification

Al Globus wrote:

> The only thing this costs is mass,
> and if mass is plentiful (asteroidal and lunar material is *fairly*
> cheap,
>
> Mass and energy never cost anything. Only people cost money (when was
> the last time a rock demanded money from you?). Mass and energy
> *appear* to cost money because you need to pay the people that control
> them. Still, you pay the people, not the asteroid or energy source.
> This is an obvious, critical, and often forgotten truth.

Yes, I wasn't forgetting it. Energy costs something because you need
power plants to harvest the suns energy, and pay for any maintenance it
might need; so the power plants cost something because somebody spends
time building it for you.

The mass costs because it needs 'mining' (you need to pay the miner).
Also you need to pay for the launch costs- it requires fuel/power
for a rocket or mass driver, and you need to pay for the people
operating/maintaining the equipment/rocket and anything else
necessary.

Asteroidal material may well be cheaper- ion drives can be used for
transport and the equipment may be cheaper to run and less mass
intensive. But the shipping delay is likely to be months or even
years, so won't be available at high orbit initially. Clearly
the costs of materials is going to vary over time- very expensive
early on- very cheap later as mass production gets underway.

Still, I am wondering about the law of the minimum. Growth is
limited by whatever is in shortest supply. Energy isn't in
short supply. Mass in general might be, although there is a fair
amount albeit it very spread around ("Space is big, really big, you
won't believe how mind boggling big...").

Right now, some of the volatiles might be fairly rare away from
the main belt- i.e. water/hydrogen, nitrogen etc. I'm wondering
where we would get that from. The lunar poles may have some,
although it might be not in sufficient abundance to be worth
mining- but we don't know; and we need to find out.

--
- Ian Woollard (ian.woollard@...)

"Is a planetary surface the right place for an expanding technological
civilization?"
- Gerard O'Neill