In Episode V, Darth Vader was so hell-bent on capturing Han Solo and his fellow rebels that he ordered his Star Destroyers into an asteroid field, fully aware of the potential damage. Han noted that the Empire "would be crazy to follow them" into the asteroid field. He was right: it was only after suffering destruction and casualties that the Empire actually started shooting the asteroids. At one point, a massive asteroid hit a Star Destroyer, and the hologram of one of Vaders commanders disappeared. It was as if Vader knew that there would be damage to his fleet, but showed complete disregard for everyone other than himself and his master, the Emperor. Obviously these Imperial commanders were either terrible at interstellar travel, or were just presented as complete bumbling idiots for the viewers. It was a continuation of the portrayal of the Empire as this incredibly vast and powerful, yet incredibly stupid organization. It seemed so dumb for the Millennium Falcon to constantly be so close to the Empire, yet fully capable of escaping them time after time.