Let me fact find; so the main asteroid belt is 400 million km away (2.7 A, outside Mars)and the Moon is 384,000 km away... Since it's a thousand times closer I take your point, maybe mass drivers on the Moon would be more practical. How much material collects at the Earth-Moon lagrange points I wonder? *googles* Oh, just dust, never mind.
I think long term, asteroid mining is best for sourcing materials for space-based construction, but it's very long term perhaps.
Here's an interesting article on mining asteroids, they do have the advantage of being massively metal-rich;
In the 2,900 cubic kms of Eros, there is more aluminium, gold, silver, zinc and other base and precious metals than have ever been excavated in history or indeed, could ever be excavated from the upper layers of the Earth's crust.
and here's a bluesky article that's quite funny to read. |