This ignores the spirit of human exploration, which is not solely for economic benefit. No one climbs Everest, or completes a solo Arctic expedition, looking for "resources". NASA has given us an incredible amount of knowledge and perspective on the solar system for a trivial amount of money (it was about .5% of the US Federal budget before being slashed at the behest of the Tea Party).
Spirit of human exploration has always been economic. Whether the Vikings, Columbus, Conquistadors etc, the quest was always based on expanding resource base. Those were true exploration, the mount Everest was useless and foolish.
Listen I am not against the space program, but we should be using the resources to create a real defense against Comets, Meteorites etc.
That I see a need for, but going to the moon? So that we can go to another barren planet? What for?