[wilsonnb2]

> Well, unless we outlaw reproduction without government approval we will hit the limit of what the planet can support as far as human life.

The birth rates of richer nations are significantly lower than the birth rates of poorer nations. I'm not convinced that overpopulation will be an issue as long as we can provide cheap and easy access to birth control to the entire population.

> asteroids contain unfathomable amounts of rare and common elements that will be easy to exploit once the appropriate technologies are developed

This is actually my favorite justification for space exploration, but if this is our goal, we should be focused on asteroid mining and not moon bases or manned mars missions.

> Space exploration will continue to add more and more technological and general scientific breakthroughs

You don't know this. It's just a guess. No one can know if the side effects from space research will prove to be more or less useful than the side effects from cancer research or any other kind of research. It's not something that can be known.