The Galaxy Gun, also known as the Galaxy Weapon, represented a superweapon of immense power, brought into existence by the Galactic Empire in 10 ABY. Its construction was ordered by the "reborn" Emperor Palpatine, with Umak Leth serving as its designer.
The Galaxy Gun was a space station shaped like a cannon, stretching 7,250 meters in length, and it was constructed above the planet Byss. To put its size in perspective, the Galaxy Gun's length was almost five times that of an Imperial-class Star Destroyer. Equipped with sublight thrusters and a Class Six hyperdrive that was rather slow, the Galaxy Gun remained permanently positioned in orbit around Byss.
The Galaxy Gun's singular purpose was to launch missiles that carried particle disintegrator warheads, frequently referred to as "lightspeed torpedoes". These enormous and devastating explosives were launched from the Galaxy Gun before jumping into hyperspace, allowing them to reappear at specific locations practically anywhere in the galaxy. Each missile boasted a swift hyperdrive, granting it hyperspace speeds comparable to the Millennium Falcon. Once launched, a missile could traverse the distance from the Deep Core to the Outer Rim in a matter of hours.
Upon exiting hyperspace, the projectile would lock onto its designated planetary target. As the missile hurtled toward its destination, integrated defensive systems would activate to safeguard it. Automated laser cannons engaged approaching enemy vessels and starfighters, while robust deflector shields and armor plating shielded the missile from ion cannon and turbolaser fire.
As it neared its target, the power core would energize the particle disintegrator warhead. Upon impact with the planet, the energized warhead would detonate, initiating a cascade of nucleonic chain reactions that would spread across the surface, transforming matter into energy and consuming everything in its path. The missile featured adjustable power settings; at maximum power, it could obliterate an entire world if the nucleonic reactions persisted until all available matter was consumed. However, lower power settings enabled its use as a tactical weapon, capable of targeting and destroying a city or military installation while leaving the rest of the planet intact.
In 10 ABY, the Galaxy Gun was secretly built in orbit above Byss at the command of Emperor Palpatine. Palpatine's intent was for the Galaxy Gun to serve as a new instrument of terror, allowing him to crush the New Republic and reassert his galactic dominance. The Galaxy Gun was stationed at Byss, protected by the massed Imperial fleet. Any attempt to destroy the superweapon would have forced the New Republic to launch an almost suicidal assault on the most heavily defended planet within the Empire.
As retribution for the New Republic attack on his citadel and the subsequent escape of surviving Rebels and a group of smugglers into hyperspace, Palpatine authorized the launch of the first projectile against the New Republic base on Pinnacle Moon.
Within mere hours, Pinnacle Moon was utterly wiped from existence. However, due to the presence of spies within Byss, New Republic forces, along with some native Ixlls, managed to flee the doomed moon aboard a fleet of transports.
The New Republic responded by sending commando and sabotage teams to attack the Galaxy Gun, but they were decimated by the overwhelming Imperial fleet. The Emperor persisted in launching projectiles, annihilating entire rebellious worlds and nearly crippling the New Republic. Krinemonen and Hirsi suffered immense devastation from the gun's attacks. This terrifying strategy allowed the Empire to swiftly reclaim crucial territories in both the Inner and Outer Rims. Other known targets included Nespis VIII's Space City, where even the New Republic's Kuat V-200 ion cannons were unable to breach the projectiles' shielding, and the New Republic troopship Pelagia, commanded by Captain Tekba, which was carrying one hundred thousand troops when it was destroyed.
Ironically, Palpatine's excessive reliance on the Galaxy Gun ultimately contributed to his downfall: several Imperial officers, disturbed by their clone Emperor's increasingly erratic behavior, conspired with Royal Guard member and Lumiya's Sith Carnor Jax to tamper with the Emperor's genetic material at its source.
Despite its immense firepower, the Galaxy Gun met its end in 11 ABY, along with Byss and much of the amassed Imperial fleet. Following the Emperor's final demise at the Battle of Onderon, the renowned astromech droid R2-D2 seized control of the Eclipse-variant super star destroyer Eclipse II's computer systems and directed the ship on a collision course with the Galaxy Gun. The Galaxy Gun, too cumbersome and slow to evade the incoming Super Star Destroyer, suffered catastrophic consequences.
The resulting explosion annihilated both superweapons. Among those killed in the Galaxy Gun's destruction was Umak Leth, the engineer responsible for its design. However, one final projectile was launched just before the destruction. The unguided missile was drawn in by Byss's gravity and drifted toward the planet. The particle disintegrator warhead then detonated, obliterating Byss and decimating the majority of the reborn Emperor's forces and loyal officers. The Galaxy Gun's destruction of Byss and its inhabitants played a significant role in ending Operation Shadow Hand.
Nearly fifteen years later, during the Yuuzhan Vong War, Luke Skywalker would almost lament the Galaxy Gun's destruction, believing it could have aided the New Republic in eradicating thousands of Yuuzhan Vong Koros-Strohna worldships. Over a century after Palpatine's death and the Yuuzhan Vong invasion, Vul Isen of the One Sith developed viral spores capable of poisoning planets. When confronted by Cade Skywalker, Isen boasted that the Galactic Empire no longer needed the Galaxy Gun or the Death Star to destroy planets, thanks to his scientific advancements.
