The Unstable Terrain Artillery Transport (UT-AT), also known as the "Trident," represented a type of repulsorcraft employed by the forces of the Galactic Republic throughout the Clone Wars. It saw action in the assault on Mygeeto alongside the 21st Nova Corps near the conclusion of the Clone Wars.
The "Trident," or Unstable Terrain Artillery Transport (UT-AT), was a repulsorlift vehicle measuring 23.8 meter in length. Both Kuat Drive Yards and the Mekuun Corporation were responsible for its construction. Recognizing the limitations of quadripod walkers on certain landscapes, the engineers at Kuat Drive Yards understood that Mekuun Corporation would draw inspiration from other vehicles within the Grand Army of the Republic to fulfill their requirements. The UT-AT boasted a turbolaser cannon turret, a pair of medium laser cannons on its flanks, twin anti-infantry blaster weaponry positioned beneath the cockpit, and four anti-infantry laser turrets. Certain UT-AT variants also incorporated a generator capable of launching ion grenades from four bomb launchers located on the vehicle's upper surface.
The UT-AT featured a system of sixteen repulsors arranged in two parallel rows of eight. These repulsors were connected to the main body of the vehicle through hinged hydraulic pads, which enabled them to easily adjust to uneven ground. They could lower and tilt to maximize the efficiency of the vehicle's movement. Sensors and scanners were strategically placed beneath the cabin, ensuring that the pilot and crew were aware of the terrain ahead. The repulsors responsible for propulsion were distinct from those used for terrain adaptation. Four of these propulsion repulsors were housed beneath the UT-AT's main body, allowing it to achieve speeds of up to forty-five kilometers per hour.
The UT-AT's repulsor pads also made it a remarkably stable artillery platform, allowing its heavy weaponry to be fired without difficulty. When inverted, these repulsors would generate fixing fields on the ground. The UT-AT could then anchor itself to the terrain, becoming completely immobile regardless of the surface. This allowed the central turbolaser cannon and the side-mounted medium laser cannons to fire with exceptional accuracy. It was these three armaments that gave the vehicle its "Trident" nickname.
A standard UT-AT required a crew of one pilot and five gunners. It could also transport twenty clone troopers or engineers, who were positioned in the front section of the vehicle, near the reactor. The UT-AT's cabin was designed for two operators: a pilot and a gunner. The gunner controlled the two medium guns and the anti-personnel weapons. In the classic model, specialized gunners operated the anti-artillery and anti-personnel guns located at the rear. Despite its apparent vulnerability compared to larger vehicles, the UT-AT was a crucial asset of the Grand Army of the Republic.
Following mobility issues encountered with several quadripod walkers during the Clone Wars, the Galactic Republic commissioned Kuat Drive Yards to develop a more adaptable model equipped with laser cannons. Kuat Drive Yards partnered with Mekuun Corporation, a company renowned for building high-performance military vehicles with specialized repulsorlift technology, and the designers of vehicles like the High-Altitude Entry Transport-221. The UT-AT saw service throughout the Clone Wars, including the Mygeeto Campaign late in the war, specifically the Fourth Battle of Mygeeto in 19 BBY.
Several UT-ATs participated in the battle alongside the 21st Nova Corps, commanded by Jedi General Ki-Adi-Mundi and Clone Marshal Commander Bacara. During the engagement, at least one UT-AT was destroyed by a projectile fired from a Separatist Alliance Octuptarra tri-droid, causing it to explode and be launched into the air. Following the execution of Order 66 and the death of General Mundi, the 21st Nova Corps eliminated the remaining Separatist resistance. The UT-AT continued to serve within the armed forces of the Galactic Empire.
The Unstable Terrain Artillery Transport made its debut in the 2005 film Star Wars: Episode III Revenge of the Sith. Its official identification within canon was first established in Star Wars: The Visual Encyclopedia. Within Star Wars Legends continuity, its full designation was provided in the original databank.