Precious metals make up a significant fraction NEAs by mass, and even one metallic
asteroid of 1 km size and fair enrichment in platinum-group metals would contain
twice the tonnage of such metals already harvested on Earth. There are 1000 NEAs
with a diameter of greater than 1 km. Capturing these asteroids around the Earth would
expand the mining industry into an entirely new dimension. Having such resources
within easy reach in Earth’s orbit could provide an off-world environmentally friendly
remedy for impending terrestrial shortages, especially given the need for raw materials
in developing nations.