Click here for Wookieepedia's article on the Canon version of this subject.  This article covers the Legends version of this subject. 

"The ion cannon will fire several shots to make sure that any enemy ships will be out of your flight path."
Princess Leia Organa[src]

The v-150 Planet Defender was a surface-to-orbit ion cannon produced by Kuat Drive Yards.


Schematics of the v-150 Planet Defender on Hoth

Manufactured by Kuat Drive Yards, the v-150 Planet Defender was a massive, independently powered, surface-based ion cannon designed to target and neutralize starships in orbit of a planet. The v-150 was usually mounted on a rotating base, and the weapon itself was covered by a semi-spherical shell of reinforced permacite. The weapon was designed to be modular, with an installation time of only a few hours.[1]

Each weapon was sold with its own reactor, which was intended to be buried forty meters below the weapon emplacement. Three levels of crew quarters and storage space were located between the reactor and the weapon, and the emplacement could store enough supplies to last the crew of twenty-seven for three months.[1] When activated, it took several minutes for the v-150 to maneuver into position on its rotating base.[5] The v-150 was completely immobile, and was vulnerable to attack from ground forces and aerial bombardment. A retractable blast shield protected the weapon, and the cover had to be retracted to fire the weapon.[4]

The v-150 took targeting data from electrotelescopes and long-range sensors, and could also be linked to orbital sensor stations for more accurate targeting. The weapon had an optimum range of 4,000 kilometers, and a maximum range of 180,000 kilometers.[4] The v-150's fire-control computers allowed the v-150 to target orbital ships at will, and a single ion bolt could disrupt Imperial-class Star Destroyers.[1] The weapon had a fire rate of one shot every six seconds.[5]

The v-150 was commonly employed in conjunction with planetary shields; as planetary shields were expensive to maintain, planets only powered them up when they were needed. Even then, the shields could take several minutes to reach full power. It was during these minutes that the v-150 was vital to planetary defense, targeting enemy vessels in orbit before the shield could reach full power.[1]

The v-150 was expensive,[1] costing between 500,000[2] and 1.5 million credits,[3] which was a quarter of the price of a full planetary shield.[1] Planetary ion cannons were synchronized with planetary shields to allow the weapon to fire through the shields by lowering them for a split second. Even with the rotational base, each ion cannon had a limited fire vector of a few hundred square kilometers, so they were placed to protect vital bases, shield generators, spaceports and cities.[5]


The v-150 Planet Defender was first proposed by a Gathi working for CoMar Combat Systems named Can Lar. CoMar rejected his proposal, stating that the design was "militarily useless and an engineering impossibility." In response, Lar quit CoMar and attempted to find an employer that would take his design seriously. He found it in Kuat Drive Yards.[1]

Many Imperial planets bought v-150s to supplement their defense setup and to reduce the cost of keeping their planetary shields active.[1] The planetary ion cannons used by the Alliance were stolen during a hijack of a super transport in the Kuat system. The ion cannons were assigned to Echo Base on Hoth, and Bulwark. The others were at highly classified locations.[6]

The Bothan colony Kothlis was protected by a hidden V-150.[7]

A v-150 Planet Defender on Hoth

Alliance crews referred to the weapon as the "150," and it was the single most powerful weapon in the Alliance's ground-based arsenal. However, despite the expense and usefulness of the weapon, it was considered a disposable weapon to use in desperate circumstances, and abandoned during the evacuation. On Hoth, the crew manning the ion cannon were soldiers from Alderaan who were willing and eager to die at their posts to aid the Rebellion and hurt the Empire.[8] Targeting data for the v-150 on Hoth was supplemented by Echo Base's electrotelescopes and long-range sensors.[5] Its power generator was remotely connected to the base's main reactors, which were scavenged from a Praetor-class Star Battlecruiser. While v-150s were usually powered by reactors located forty meters below ground, the Echo Base generator was buried a full kilometer below the icy surface.[9]

Before its abandonment, the cannon provided valuable cover fire for the escaping transports of Echo Base as they attempted to run the blockading line of Death Squadron's Imperial-class Star Destroyers orbiting Hoth.[10] From the base's command center, head controller Toryn Farr[11] directed the ion cannon to fire upon the Imperial I-class Star Destroyer Tyrant, disabling it as the GR-75 medium transport Quantum Storm, the first transport to evacuate Hoth, slipped past the Imperial warship and entered hyperspace. The Alderaanian crew stayed at the posts until the end of the battle, then set the v-150 to explode to cover the last transports.[5]

However, the cannon itself was structurally intact and operational when Jaden Korr arrived in 14 ABY searching for the Disciples of Ragnos.[12] Two v-150 cannons were also present during Kyle Katarn's mission to Artus Prime.[13]

The New Republic used v-150s to defend poor but strategically important worlds. They proved almost useless against the Yuuzhan Vong's biotechnology.[4]

Behind the scenes[]

Concept art of the v-150 by Ralph McQuarrie

The v-150 Planet Defender first appeared with the release of Star Wars: Episode V The Empire Strikes Back and its tie-ins. The ion cannon at Echo Base subsequently appeared in many sources. One source states that the ion cannon was destroyed to cover the Rebels' escape, although two other sources contradict that. In Star Wars: Galactic Battlegrounds, a 2001 video game, the player is assigned to destroy the ion cannon and must do so before proceeding to the next objective. In Star Wars: Jedi Knight: Jedi Academy, a 2003 video game, the ion cannon at Hoth is intact. This article incorporates information from all three sources.

The ion cannon appears in the background of the Hoth map skirmish mission in the video game Star Wars: Rogue Squadron III: Rebel Strike. It fires throughout the match.



Notes and references[]