I didn't sign up to do a post on the 20th originally because I thought I might be traveling to the USA, that day, plus I'm in the middle of finishing my paper. This is actually the 21st for me, but I guess in the US timezones it is still the 20th.
Rather than a long post on an overall vision and rationale for space settlement, which I believe other bloggers can do
better, I will just throw together a number of statements that summarize my own ideas and opinions.
I strongly believe in the concept of space settlement driven by non-government organizations. By this I mean private enterprise, and settler organizations. I'm not sure that it is inevitable, but it surely ought to be. My concept of space settlement is technology driven. I believe that people will venture into space when the tools and infrastructure are available for us to stay. Tools will include, for example, advanced tele-operated robots, and infrastructure will include long term maintainable life support systems, energy harvesting systems such as large solar concentrators, and magnetic field generators for protection against charged particles. While I think there will be a significant element of risk, the environment should be such that we can, for the most part, stay safely within a maintainable technology framework, with plenty of redundant options should anything go wrong.
I'm an asteroid settler, myself, rather than a Mars or Moon settler. By this I mean that I think that asteroids are likely to be the first places to be settled and will be much easier to access than gigantic clumps of round matter at the bottom of steep gravity wells. I'm predicting that most prospective settlers will prefer to live in approximately 1 earth g. and have some prospect of returning to earth, and will adapt quickly to the coriolis forces present in a rotating habitat.
I think the first settlers will not be in it for the money or even the thrills. Being one of the first off earth settlers is going to be like basically volunteering for the 21st or 22nd century's version of a lifetime of backbreaking labor. The only way the first habitat will be built is by a group of settlers who know that this will be their only option for survival in the long term. They won't be receiving much, if any, monetary benefit, but they will at least obtain their wish of being able to set up a mini-society in whatever way they wish, and having some likelihood that the people around them will share the same values.
Unless the space elevator is built, access to space is going to remain somewhat expensive, at least compared with air travel. I know many space enthusiasts are hoping for a vast low earth orbit infrastructure which can provide settlers with the materials they need. I'm not sure this will be the case. Settlers may have to be almost self sufficient, with the exception of certain high value, low mass products, such as medicines, ICs and precision mechanical devices. I think it is an important field of study to understand the technology necessary to maintain a colony with a limited mass flow rate, and mass transfer latency into the colony, and the period of time the colony can be entirely self sufficient based on their level of technological capability and resources.
Nothing is free, and the settlers will be paying for whatever supplies they receive somehow. I somehow feel that minerals from commercial mining ventures will not be one of the first exports. The initial exports are likely to be information. First, there will be a lot of interest on earth in the daily lives of these settlers. This could be one of the most valuable exports for quite a long period of time, until space travel becomes commonplace. Secondly, there will be much scientific knowledge to be gleaned from the environment around the settlement, for example observations of the sun and other planets, and detailed research on the composition of the asteroid itself. Later, high quality zero gravity research may also be conducted relatively cheaply by settlers.
Lastly, I'd just like to comment that although most of our focus is on finding better ways of getting out of earth's gravity well, there are other, just as important, fields of research that need our attention in order to spread civilization to beyond the planet. I suggest that space agencies in various countries that can't afford a large space program can participate in this kind of research in a really meaningful way. For example I would love to see Australia start a space program based not on developing launch vehicles, but on applying its considerable mining expertise to ways of harvesting materials from asteroids, and using them to build structures. That's a space program I could really be supportive of!