Cosmic Radiation

--- In spacesettlers@yahoogroups.com, Michael wrote:
> Hi,
>
> >Planets, as far as human settlement goes, should be avoided.
>
> A sustainable ecosystem, base on Terran life, cannot exist in a
space
> settlement smaller than the surface area of a planet. Smaller space
> settlements are only temporary. Storage, transportation hubs,
mining
> colonies. It's only when they reach a surface area similar to a
planet that
> they can become sustainable.

Are you needling us? :-) OK, let's have some fun.

I'm not sure if you're making a statement of fact or asking a
question. If fact, I'd need to see something to back up your
position.

First off what do you mean by a sustainable ecosystem? A closed
cycle? If so, then we may not need to. A close enough system may be
adequate.

Secondly, perhaps humans can live in a ecosystem that only meets
their needs and not those of krill and plankton and all of the
organisms higher up the food chain. Perhaps our ecosystem will be
more limited and easier to sustain. Considering the population
density we'll probably have, I'd compare it to the ecosystem needed
to keep NYC going. Not much NEED for bee, birds, trees, lakes,
rivers, savanah, etc.

If we do need a sustainable system, we may not need to recreate all
of the self-regulating processes of Earth. We'll also have a number
of processes that we need to improve either mechanically, or
systematically, such as heat radiation and waste reclamation. If we
engineer those processes the others may be self-regulating or not.

> > But keep your family alive and safe in space. It's easier to
control
> >the thermal conditions and air quality of family-sized
> >interconnectable mobile habitats than an entire planet.
>
> Safe? Your family will die from cancer and your children will be
mutants
> because of cosmic radiation. The equivalent of 14 foot of concrete
or a
> planetary atmosphere is required to protect from cosmic radiation.
>
> The thermal conditions are easier to control but they are also at
extreme
> risk of sudden and catastrophic failure. A self-regulating system
like a
> planetary ecosystem is stable by comparison.
>
> Michael

I think the correct figure you meant to quote was 6 ft of dirt
around the shell of smaller Habitats will approximate the radiation
dosage equivalent to Denver. Can anybody else backstop me on this?

For the larger Habitats, usually the thickness of the pressure shell
and the thickness of the atmosphere is sufficient protection.

I'm not sure how you mean that the thermal conditions of the
atmosphere is prone to catastophic failure? That would take a means
of extracting a lot of calories from the atmosphere in a very short
time. How could that be done?

Let's see where this goes?

TangoMan