Thoughts on Colonization

Can't resist the temptation to nit-pick a bit, since colonization location is one of my favorite debates:

In regard to Mercury:
> It has ample sunlight to power the colony

Half the time. I'd sooner get outside the shadow of any planet or moon than get closer to the sun in pursuit of power.

> The
> benefit to colonizing Mercury would be that it is a way station en
> route to the Outer Solar System.

How could a location deeper in the gravity well of the sun be a way station to the Outer System?

In regard to Venus:
> The planet's intolerable heat is a source of energy that can be
> harnessed.

To harness heat energy for power, you need a hot end and a cold end.

> If colonization of the
> planet is to take place, then it should happen on the surface--

I'm not aware of any near-term technology which would allow us to survive the pressures or the temperatures. This is the reason why some discuss floating cities (although I agree with you that a civilization up to that challenge will probably already be finding orbital habitats better options).

> It has been suggested that even solar storms do
> not produce enough radiation to cause serious health problems to
> humans (Mars is too far away).

Someone may have said this, but I'm not sure it's right. Solar storm protons are one issue, but cosmic rays are another, and they're omnipresent. I've heard that Mars surface habitats for long-duration living might only need radiation shields about 1/3 as thick as for living in orbit, but that it would be a mistake to think you don't need shielding at all.

> We could build very simple colonies by
> digging a pit in the ground and covering it with an airtight dome.

The engineering requirements for the airtight dome would be more or less identical to those for the pressure vessels of orbital habitats. The notion that Mars habitats can be simpler than orbital ones is widespread, but I always question it.

> Three moons are perfectly suited for colonization: Ganymede,
> Callisto, and Titan--

Titan is relatively benign (if we can manage to deal with a cold atmosphere dense enough to convect away significant amounts of heat), but Ganymede is too far inside Jupiter's radiation belts for humans to long dwell. Callisto might be far enough outside the belts, but that's assuming there's some advantage to being on a bigger moon, versus a smaller one even further up on Jupiter's gravity well. I tend to think in terms of orbital habitats conveniently close to small, mineable bodies. So from that view, the outermost, mountain-sized moons might come closer to being economically developed than a large Galilean moon.

> On
> Titan, this would be easy because the abundant methane can be burned
> just like hydrocarbons are on Earth.

But it needs to be burned with oxygen. Yes, I'm certain Titanians would be manufacturing oxygen, but I doubt they would be doing it for heating their homes. I think the energy costs of obtaining the oxygen would make it uneconomical for just heating. I'd say nuclear reactors would be a safe bet for Titan. The dense atmosphere would be a convenient heat sink for the exchangers.

But I agree with you completely about the advantages of orbital colonies, and that terraforming will probably prove to be unnecessary.

Regards,

Mike Combs