Into Space
Hyperlink game with the author's opinions on how we should be developing space...
Java SolarPop
Solar System Demographics of the Next Millennium
MARS
Mars base simulation game from French chapter of Mars Society. Freeware for Windows.
Moon Tycoon
Build and manage a 3D lunar colony - sim game with a range of industries and strategies.
Space Colony
Sims-style game to develop a space colony. Doesn't look terribly realistic, but cute...
SpaceColonyH
A psychologically-based, problem-solving leadership game set in a space colony.