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 very large quantities.
In 2005 NASA Administrator Michael Griffin identified space colonization as the ultimate goal of current spaceflight programs, saying:
… the goal isn't just scientific exploration … it's also about extending the range of human habitat out from Earth into the solar system as we go forward in time … In the long run a single-planet species will not survive … If we humans want to survive for hundreds of thousands or millions of years, we must ultimately populate other planets. Now, today the technology is such that this is barely conceivable. We're in the infancy of it. … I'm talking about that one day, I don't know when that day is, but there will be more human beings who live off the Earth than on it. We may well have people living on the moon. We may have people living on the moons of Jupiter and other planets. We may have people making habitats on asteroids … I know that humans will colonize the solar system and one day go beyond. – Michael D. Griffin
As of 2008, 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.