How are space probes to the outer planets such as Jupiter protected from being obliterated by collisions with asteroids in the asteroid belt?
They are not protected from collisions. What helps is that the average distance between asteroids is immense, such that one asteroid is not likely visible to the naked eye to …the next nearest asteroid. There is so much space between asteroids the ships generally pass through without any problem. Actually, the rings of Saturn are also so tenuous that the Cassini spacecraft has passed through them with no ill effect, and they are MUCH denser than the asteroid belt. (MORE)