The main goal of this site is building a plan for a permanent space presence off the surface of the Earth. To begin, I have laid out a simple plan for a 10,000 occupant, 10 million ton space station located at one of the stable Lagrangian points, where gravity truly is zero (one ahead and one behind the orbit of the Moon). A quick view of such a base can be seen here. This is largely inspired by a NASA research group's report in 1977, which unfortunately is not web-available, although an earlier report (1975) along similar lines can be had here. For various reasons, this station design and size are believed to be about the minimum for a truly permanent outpost which can achieve parts closure, or the ability to create everything it needs itself. Other plans have been put forward, both for such a station and for a variety of other types of outposts, most of which have considerable merit. This plan is designed to be a point for discussion, as it certainly can be improved, but I believe it to be a strong starting point.
To date, everything that mankind has created in space has been built on the ground and launched, either whole or in large pieces. The weakness of such a method for building an outpost the size of the one we are considering here is well-illustrated by the International Space Station (ISS). More than 30 launches (at upwards of $600 million apiece) and 5 years (on the original time table, which has slipped repeatedly) will be required to build a station which has no gravity and no radiation shielding (so missions longer than 1 or 2 years are out) and capacity for only 7 people. Additionally, the station will need all of its supplies brought in from Earth (4 or so launches a year) and is only designed to last 10 years. Using Apollo-era technology such as the Saturn V, with 5 times the shuttle's capacity, or the newer Russian heavy-lift booster at 6 times (and half the cost of a shuttle mission), it would be possible to cut the number of launches and/or increase the capabilities of a station. It should be fairly obvious, however, that even this would not make a 10,000 person station reasonable in terms of dollars or time if we build it on Earth and ship it up (and this whole argument neglects the cost of actually building the parts on the ground).
The way around this problem is to manufacture as much as we can in space. Some parts are relatively easy to do this with. Of the 10 million tons projected for the station, 9 million, or 90%, is going to be radiation shielding. The only important value for the shielding is the mass, so it can be made out of anything we can find, and there are many places that are cheaper to import bulk matter from than Earth, such as asteroids or the Moon, since their lower gravity means smaller rockets are needed. The large structural units, such as the hull and spars (75% or more of the remaining weight), are relatively simple to manufacture, and with access to basic metals and some automated systems, the work could reasonably be done in space as well. With only 250,000 tons to lift from Earth, the project is headed towards feasability. In theory, this could be continued until all parts are built in space, and it can easily be continued past the point taken here (glass and soil make up the next two most important parts, and raw materiels for both are found on the Moon). However, at some point the cost of building the construction facilities would outweigh the benefits, and we would choose to import some items from Earth. The challenge is to limit such imports as much as possible to very light, small items (such as computer chips). In this way, the cost could be kept to a reasonable (although still very large) amount that would be within the grasp of a large government or very large corporation.
Presented in the next few pages is a more detailed look at how we can build the capacity to create a station by relying primarily upon resources located in space. The plan is broken into several steps. Each builds upon the one before it, but is designed to have its own intrinsic value (i.e. step 3 is not a wasted effort if a particular organization cannot finance step 4). Intended for a private-sector company, the steps are also progressive in both their difficulty and in their payoff. Assuming that much of the project will have to be financed, tackling the various steps in order will help to alleviate the sense of risk by demonstrating competence and allowing the best selection of resources (i.e. a mining mission is preceded by a mission to actually find ore, rather than flying blind). Also, it should be noted that the entry of multiple companies at multiple stages can be of great benefit, especially to those who are unable to complete the whole progression, as they can then trade resources and information with their successors.
For ease of use, I have broken my plan down into five individual stages. They are listed chronologically by planned start date, but note that several of the stages may be occurring simultaneously and scheduling is only approximate. You can start with any of the stages, but they are presented in order.
Begin with Stage 1--Probes for the Asteroids
Stage 2--Using Asteroids
Stage 3--SeaHab
Stage 4--Moonbase
Stage 5--Space Colony