On a level where an Imperial Star Destroyer is in the enemy arsenal, shoot off its warhead launcher on the bow. This will open a hole which actually allows you to fly inside the ship and "enlighten" it from within. An added bonus is that other craft on destroyer's side will shoot it to hit you and on occasion fast movers such as TIE defenders or Avengers will ram the ship. A good tactic when dealing with two enemy capital ships (e.g. an Imperial Star Destroyer and a frigate or space station) is to shoot up the smaller vessel so it will fire at you. Then, go inside the Destroyer.