On Tuesday, October 16, 2018 at 6:14:01 AM UTC-6, Mark Earnest wrote:
...instead of being surrounded by a sphere of cataclysmic asteroids and colliding

space debris? No one knows.

NASA knows. small roids also orbit Saturn and near the rings, they 'move' the particle along. also when space ships need to exit the big planet they can manipulate a path. and close it back up. Otherwise, outsiders are out of luck upon approach.