[Source] The v-150 Planet Defender, also known as the v-150 ion cannon, was a model of planetary ion cannon designed to disable capital ships. Often deployed in conjunction with planetary shields, its purpose was to defend planets while the shields reached full power. It could disrupt Star Destroyers with a single ion bolt, however its stationary nature made it vulnerable to attack, and its blast shield was required to retract in order to utilize the cannon. It was also equipped with an independent power generator buried roughly 40 meters below the weapon emplacement.