Smacking Asteroids For Resources
Video by Eric Brueton Summer studies of space settlements by Gerard O'Neill and NASA in the 70s and again in the early 90s both determined that significant amounts of mass is required for passive radiation shielding. Although structurally, most designs call for refined steel, it has been suggested that mass for the shielding could just be raw lunar regolith, left-over slag from future on-orbit industrial processing, or obtained from the asteroids. The asteroids are seen as preferable as, in terms of delta-v, they are most easily available. The typical argument is that a long duration mission to rendezvous with a near-Earth asteroid or comet (collectively, near earth objects, or NEOs) could skip a lot of launches from deep gravity wells, either digging into the NEO or dismantling and processing it to make a nearby structure, or both. The wrinkle, however, is in that "long duration" part. In terms of delta-v, there are NEOs which are easier to hit than the Moon, ...