By shielding, do you mean that astronauts could live inside or behind the asteroid, just using its mass between them and the sun? That would be pretty dark and cold. As far as I know, no asteroids have major magnetic fields.<p>I am totally with you on using the asteroids for materials, but I am not sure that they would provide useful gravity either. Even one of the largest near-earth asteroids, 433 Eros, only has a surface gravity of 0.0059 m&#x2F;s^2. Is that useful?