The inherent risks of keeping all humans on this planet (rogue asteroids, exploding supervolcanoes, etc.) naturally lead one to think about getting at least some human beings off-planet. Whether it's L-5 habitats, lunar colonies, or emigration to Mars (and, yes, the "space community" contains factions devoted to each), it makes eminent sense to leave Earth behind. RocketForge provides plenty of links to some recent debates about abolishing or downsizing or refocusing NASA and such, but the most eloquent statement is one made by RocketForge editor Michael Mealling:
Forget exploration, science and spinoffs. The fundamental reason that the US should be involved in space is that Americans want to go there. Now. They want to go there to build wealth, to live, and to form empires that dwarf anything humans have ever conceived of.
It is the same reason people built an airline industry. No one flies in a 747 to explore the air. They simply want to get from Point A to Point B very quickly. Space isn't about exploration or any other feel good, politically correct, Mr. Rogers notion of a "noble cause to understand our universe." It's about that sweaty, churning mass of love, hate, fear, greed, opportunity and universe-changing potential that makes humanity what it is.
Amen.