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 had to retract in order to utilize the cannon. It was equipped with an independent power generator buried roughly 40 meters below the weapon emplacement.
Prior to the Battle of Hoth, the Alliance to Restore the Republic used a v-150 to allow their transports to slip past Imperial Star Destroyers. Coordinated by Commander Toryn Farr, the cannon did its job well and disabled at least one Destroyer, the Tyrant, allowing the first of the Rebel transports, the Quantum Storm, to escape into hyperspace.
The v-150 Planet Defender first appeared in The Empire Strikes Back and was based on concept art by Ralph McQuarrie. Although Star Wars: Galactic Defense established that the canon was destroyed during the Battle of Hoth, Star Wars: The Rebel Files stated that it wasn't destroyed, and eventually recovered after the Battle of Endor, although its internal mechanics were damaged by Hoth's climate.
Concept art of a v-150 by Ralph McQuarrie
The v-150 Planet Defender first appeared in The Empire Strikes Back and was based on concept art by Ralph McQuarrie. Although Star Wars: Galactic Defense established that the canon was destroyed during the Battle of Hoth, Star Wars: The Rebel Files stated that it wasn't destroyed, and eventually recovered after the Battle of Endor, although its internal mechanics were damaged by Hoth's climate.