Galaxy Gun The Galaxy Gun , or Galaxy Weapon , was a superweapon built by the Galactic Empire in 10 ABY . It was commissioned by the " reborn " Emperor Palpatine and designed by Umak Leth . Description . The Galaxy Gun was a 7 , 250 - meter - long tube - shaped space station built above Byss . It was a superweapon capable of firing large , destructive projectiles equipped with particle disintegrator warhead s capable of destroying an entire planet . It was also equipped with hyperdrive and sublight thrusters . Each of these projectiles was capable of traveling through hyperspace with a speed equivalent to at least a Class . 75 hyperdrive , allowing for quick traversal of interstellar distances and difficulty in detecting them until they struck . Upon exiting hyperspace and homing in on its target , the projectile ' s automated defenses would activate to deter enemy forces . Automated laser cannon turrets exchanged laser fire with warships while thick armor plating and powerful energy shields deflected even the most advanced ion cannons and turbolasers . Having reached its target , powered by the missile ' s power core , the particle disintegrator warhead exploded , triggering immense nuclear cloud reactions that encircled the targeted world ' s surface within minutes . At the projectile ' s full power setting , the nuclear reactions were sustained until all matter had been converted into energy , effectively wiping the planet and its inhabitants off the face of the galaxy . However , there were low power settings allowing them to destroy selected cities and military bases while leaving the rest of the planet untouched . Luke Skywalker , when reflecting on these capabilities , noted that Galaxy Guns were the most destructive superweapons at the time of the conflict . Operational history . Like the Death Stars before it , the Galaxy Gun could have been used by the reborn Emperor Palpatine to rule with a Tarkin Doctrine - like policy of fear . To ward off New Republic attacks , the Galaxy Gun was constructed and maintained over the orbit of Byss which was surrounded by the massed Imperial fleet . In retaliation for the New Republic attack on his citadel and the escape of the surviving Rebels into hyperspace along with a group of smugglers , Palpatine ordered the launch of the first projectile against the New Republic base on Pinnacle Moon . Within hours , Pinnacle Moon had been wiped off the face of the galaxy . However , due to the presence of spies in Byss itself , the New Republic forces along with some of the native Ixll s managed to escape the doomed moon in a fleet of transports . In response , New Republic commando and sabotage teams attacked the Galaxy Gun , but were annihilated by the massed Imperial fleet . The Emperor continued to launch projectiles , destroying entire unruly worlds and nearly crippling the New Republic . Krinemonen and Hirsi were devastated by the gun . As a result of this terrifying tactic , the Empire regained key territories in the Inner and Outer Rims in a relatively short time . Other known targets included Nespis VIII ' s space city , where even the New Republic ' s Kuat V - 200 ion cannon were unable to penetrate the shielding of the projectiles , as well as the New Republic troopship " Pelagia " under the command of Captain Tekba , which was carrying a hundred thousand troops at the time of its destruction . Ironically , Palpatine ' s excessive usage of the Galaxy Gun would end up being one of the major factors that led to his downfall : several Imperial officers , disturbed at their clone Emperor ' s erratic behavior , arranged for Royal Guard and member of Lumiya ' s Sith Carnor Jax to have the Emperor ' s genetic material tampered with down to the source material . Despite the vast firepower possessed by the superweapon , the Galaxy Gun would be destroyed in 11 ABY along with Byss and much of the massed Imperial fleet . With the Emperor ' s final death at the Battle of Onderon , the famed astromech droid R2 - D2 took control of the immense " Eclipse " - variant super star destroyer " Eclipse II " ' s computer banks and set the ship on a collision course with the Galaxy Gun . The Galaxy Gun was too clumsy and slow to evade the colliding Super Star Destroyer , which had devastating consequences . The resulting explosion destroyed both superweapons . One of the victims killed in the destruction of the Galaxy Gun was Umak Leth , the engineer who designed the superweapon . However , one last projectile exited the firing tube just before its destruction . The unguided missile was pulled in by Byss ' s gravitational field and drifted toward it . Then , the particle disintegrator warhead detonated and destroyed Byss , crushing the majority of the reborn Emperor ' s forces and loyal officers . The destruction of Byss and its inhabitants by the Galaxy Gun was a major factor for the ending of Operation Shadow Hand . Legacy . Nearly fifteen years later during the Yuuzhan Vong War , Luke Skywalker would almost regret the destruction of the Galaxy Gun , as it could have helped the New Republic wipe out thousands of Yuuzhan Vong Koros - Strohna worldships . Behind the scenes . In the online game " Death Star Designer " , Galaxy Guns can be added to a player ' s Death Star model . It could be developed for 300 billion credits .