RE: ASTRONOMY: Dyson redux

From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Wed Jan 08 2003 - 12:13:49 MST


On Wed, 8 Jan 2003, Harvey Newstrom wrote:

> Unlike the rocky asteroids in the inner asteroid belt, these have
> water ice and CO2. That means they can easily be self-sustaining.

Well, you still need some trace metals, and these are mostly going to
be found in the inner solar system.

> Hydrogen to burn, water to drink, carbon for structures and
> organics.

Not so fast Harvey -- you can't burn the hydrogen unless you can
split it from the water. That requires energy and you don't have
much have that (at least the solar variant) in the Kuiper belt.
So while I agree with much of the rest of your comment, I don't
think we will see Kuiper belt colonization until we have "real"
fusion reactors. That gets "iffy" because current reactor designs
I believe call for lithium blankets to capture the heat from the neutrons
and lithium is a rare element, perhaps even more so in the Kuiper belt.
(Lithium abundance in the sun is similar to that of Selenium or Strontium
so it isn't a particularly common element). Alternate fusion cycles
require the use of Helium-3 and that requires setting up mining operations
on either the surface of the moon or the atmosphere of Jupiter.

So, the plutinos are off-limits until you can get fusion reactor
technology to the level that its "affordable" by a small group
of people (at least IMO). [Spike may chime in here about building
huge solar collecting arrays out of very thin material -- but to
the best of my knowledge you need either metals (Al, Au, etc.)
or perhaps Be to reflect light or IR. Those are also likely to
be in short supply in the Kuiper belt.]

Robert



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