Planetary Ion Cannons are powerful ground weapons that produce intense energy beams that can reach into low orbit and disable some of the largest capital ships. As with smaller ion weaponry, a planetary ion cannon causes no physical damage, instead fusing and blowing circuitry aboard the target ship and knocking out its drive engines, weapons, shields, computer systems, and other electronic systems.
The KDY v-150 Planet Defender consists of a spherical permacite shell, and its power is supplied by a massive reactor that is normally buried nearly forty meters below ground level. When activated, it takes several minutes to maneuver the ion cannon into position on its rotating base while the blast shield retracts to expose the actual cannon. A crew of twenty-seven soldiers is needed to operate the weapon and handle the targeting computers.
Ion Cannons are often used to supplement planetary shields, which take several minutes to activate and are impractical to maintain at all times because of the tremendous energy demands. Since enemy ships often appear without warning, planets rely on ion cannons and similar weapons, such as the more expensive planetary turbolasers, to provide covering fire until the shields can be raised.
Ion Cannons can be synchronized with the defensive shields for strategic defensive fire. The shields are lowered for a split second, allowing ion cannons to fire several volleys and inflict serious damage on orbiting enemy vessels. The shields are then raised before the enemy can return fire.
Each ion emplacement has a limited fire vector, meaning that it can protect an area of no more than a few hundred square kilometers. For this reason, ion cannons are placed close to vital facilities such as military bases, planetary shield generators, starports, and other major cities. Ion cannons are also limited by a low fire rate of one volley every six seconds, so multiple weapon emplacements or shields must be provided to ensure complete protection from orbital attacks and planetary landings.