NASA in the near future is about to go around the moon. They are not going back TO the moon. Why not go back to the moon and setup a launch base for deep space missions (much less Mars and asteroids). Why not plan for the future now instead of trying to do a straight shot from Earth.
Once on the moon, not only could we mine the soil for oxygen, water, hydrogen for spaceship fuel, we can also mine minerals such as Helium 3 (A rare earth element that can possibly replace Nuclear in reactors in the future).