Space Colonization (space settlement, space humanization, space habitation) is autonomous (self-sufficient) human habitation outside of Earth. It is a long-term goal of national space programs.
The first space colony may be on the Moon, or on Mars. Ample quantities of all the necessary materials, such as solar energy and water, are on the Moon, Mars, or near Earth asteroids.
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