The Atlantic: Space Adventures co-founder Eric Anderson says that mining resources from asteroids could help reduce the cost of transportation into space.
One key to making all this happen is that we need to use the resources of space to help us colonize space. It would have been pretty tough for the settlers who went to California if they'd had to bring every supply they would ever need along with them from the East Coast.
That's why Planetary Resources exists. The near-Earth asteroids, which are very, very close to the Earth, are filled with resources that would be useful for people wanting to go to Mars, or anywhere else in the solar system. They contain precious resources like water, rocket fuel, strategic metals. So first there needs to be a reduction in the cost of getting off the Earth's surface, and then there needs to be the ability to "live off the land" by using the resources in space.