How close are we to long-term human habitation beyond low-Earth orbit? Colonies on the moon or Mars are still many years off, but the good news is there are several serious efforts underway to make it happen.
The ISS. The closest thing we currently have to a space colony is the International Space Station. While it can be considered a success in terms of international cooperation and scientific research, the ISS far from self-sufficient. Sweat and urine can be recycled into fresh water and filters and scrubbers keep the air breathable, but without regular resupply missions, the station’s occupants wouldn’t last long. Still, the future looks bright up there – NASA has several ISS missions scheduled for 2010, expanding the station and adding new components (as well as spare parts).
Lunar Colonization. The best prospect for a human colony on the moon seems to be NASA’s Constellation project. The Altair Lunar lander will be able to carry a crew of four astronauts to the moon and support them there for a seven-day mission. Alternately, it can descend robotically to the moon carrying critical infrastructure for a longer-term lunar outpost. When completed, that outpost will support a crew of four for up to 180 days. NASA has a slick interactive website that explains Constellation.