Every base, even of a few settlers, is established on a stable world, in a geographical zone conducive to the development of its activity. From human memory, on the earth, the establishment of a social group was always done on a place provided at least with a source of drinking water. Next comes the proximity of game, wild fruit trees, or a land adapted to the culture, or even to breeding. Finally, the proximity of a material of construction and energy (wood, then stone, peat, thatch, etc ...), and that of metals usable to develop a beginning of industry.

On what factors, those mentioned above being simply absent, are the decision makers based on the establishment of a colonial community on a planet? We will see first the case of the expansionists: Before any arrival of settlers on the surface of a world, there is the usual ballet of the exploration and measurement robots. Probes, rolling stock, drills, automated laboratories, everything is good to define the best site of first implantation: The criteria are primarily dictated by simple geological concerns: Are there seismic danger, volcanic fault, or Exposure to storms, electromagnetic disturbances, radiation? All these considerations are studied with the utmost care. Then the work of the geologists continues to determine the possible presence of ground water, liquid or ice, and oxygen trapped in the soil. The presence of inter-resistant metals for the development of a basic industry will then be determined.

All these considerations weighed, the site of the implantation is decided. (For the beginnings of the operation of the bases, see this chapter "organization of the bases".). A community passes a symbolic course when it generates secondary bases, closer to strategic sites. The first objective of the colonists, after that of ensuring their autonomy, is to develop a sufficient industrial capacity to launch the first of the preparatory phases of terraforming, the construction of processors. When the population of the mother-base exceeds 1,000 souls, the latter takes the status of "city". It then has a small "port", at least a place where there are repair and manufacturing workshops of repellent barges, and vehicles of any kind.

When terraforming begins, the installed bases have in turn gained the status of "city". Each processor is indeed generated by a community of at least 500 settlers.