I don't think you understand what a shield world is. The main component of the Shield World is a Dyson Sphere, named The Sharpened Shield, which is located within a Slipspace bubble of compressed space-time. In normal space, the bubble has a diameter of only a few meters. The only way to access the bubble is a small portal in real-space, the Core Room Antechamber. It is located at the center of the artificial planet. You can't destroy them...