Humanity is just beginning the development of space stations. The ISS will be a vast improvement over Salyut, Skylab, and Mir; but we are still far from the realization of large space stations or colonies as envisioned by science fiction writers; at least as far as the general public is concerned. None of our space stations thus far have had any gravity. One reason is that we lack the technology to practically rotate a large structure, like a space station, to produce artificial gravity. In the future, artificial gravity will be a requirement for space colonies with large populations.
Another reason is space stations provide the opportunity to study gravity and perform research in a gravity-free environment. In the future, space stations can be entirely automated and self-contained to permit maintenance and self-repair without human intervention. These space stations would be able to monitor the earth’s resources, as well as facilitate further research in the fields of meteorology and astronomy, work that is often difficult on Earth due to atmospheric interference.
Many experiments can be accomplished in a gravity-free environment, particularly in the areas of health, chemistry, and metallurgy. In addition, space stations could serve as nodes in a worldwide telecommunications system, providing up-to-date information on the Earth’s ecosystems, the position of ships and airliners, and other information pertinent to the inhabitants of the connected world.