Available asteroid resources in the Earth's neighbourhood

Any envisioned future for space exploration involves both a growth in large space structures and a human presence in space. Some possible examples of future space endeavours are large space solar power satellites, space tourism or more visionary human space settlements. This, of course, implies a much larger mass of material in-use in space, for both structural mass and life support. The traditional approach to deliver material into orbit has always been to overcome the Earth’s gravity well, which is, arguably, not the most effective means if we bear in mind that the energy cost to reach low Earth orbit (LEO) is already “half-way to anywhere”.[“Once you get to Earth orbit, you’re halfway to anywhere in the solar system."-Robert A. Heinlein].