What if you could mine the moon?

"We're becoming a multi-world species. That will happen. The first footprints on Mars by human beings will happen in our lifetime in the next 10 to 20 years," [Bob Richards of Moon Express] says.

http://www.bbc.co.uk/news/magazine-21685995

Going to Mars is not an isolated goal. The real goal is to get man moving through space. Mars is just a small but significant jump. Imagine, on Mars the gravity is one third of what it is on Earth. That means a much smaller cost to orbit. Once in orbit, Mars is further from the sun, so it there is less cost in getting to the asteroids and to the outer planets.

Earth make a very fine home, but is very hard to get away from. This is why people keep saying that the Moon and Mars is our stepping stone to the rest of the Solar System and indeed beyond.