The v-150 Planet Defender Ion Cannon is an Anti-Orbital Ion Cannon that can disable even the largest of capital ships. These weapon emplacements are prohibitively expensive even for many Planetary Governments, they are often used to supplement planetary shields, which can take several minutes to activate and are impractical and impossible to maintain at all times due to their tremendous energy demands. They are also used to provide cover fire until the planetary shield can be raised or they can be synchronized with planetary shields for strategic defensive fire, where the shields are lowered for a split second allowing the Ion Cannon to fire several shots to inflict serious damage on the orbiting enemy ships. Then raise shields again before the enemy can react with return fire.

    Ion Cannon emplacements has a limited fire vector, meaning that it can protect an area no more than a few hundred kilometres square. Because of this Ion Cannons are placed close to vital facilities such as military bases, planetary shield generators, starports and major cities. Multiple emplacements and or shield generators are needed to ensure complete protection from orbital bombardment and planetary landings. The weapon it self is protected by a spherical permacite shell, to fire the weapon part of the permacite shell retracts and the Ion Cannon is extended out of the gap where it can fire at its targets. It takes several minutes to move the Ion Cannon into position on its rotating base. This weapon is the most expensive and most powerful ground-based emplacement in the Rebel Alliance's possession, the Rebels only allocate their few Ion Cannons to their most important bases.