Like many people the 50th anniversary of the first man on the moon is an opportunity for retrospection, and the thing that jumps out to me and to everyone is the fact that after Apollo was over we haven't been back. What does that mean for the future of space exploration, and particularly colonization, given that if colonization isn't in our future then we're going to go extinct sooner or later and probably sooner. If we assume that something resembling Moore's Law, also affects space exploration what does that tell us about when we might reach certain celestial bodies?