The idea of colonizing space has been around for a long time in the video game realm, ranging from Halo to Age of Empires. It has been arround in the realm of fiction for much longer, and is a goal for many private companies and government agencies arround the world. Space colonization (also called space settlement, space humanization, space habitation, etc.) is the concept of autonomous (self-sufficient) human habitation of locations outside Earth. It is a major theme in science fiction, as well as a long-term goal of various national space programs.
While many people think of space colonies on the Moon or Mars, others argue that the first colonies will be in orbit. They have determined that there are ample quantities of all the necessary materials on the Moon and Near Earth Asteroids, that solar energy is readily available in unlimited quantities.
As of 2010, the International Space Station provides a permanent, yet still non-autonomous, human presence in space. The NASA Lunar outpost, providing a permanent human presence on the moon, is at the planning stage. There is an ongoing development of technologies that may be used in future space colonization projects. In the Killzone universe space colonization was the best long term solution to the dwindling resources on Earth and the aftermath of World War III.