The All Terrain Armored Transport (Prototype), or AT-AT/P, was the original model of combat walker transport used by the Imperial Army of the Galactic Empire throughout the Imperial Era. It was one of several different models produced by Kuat Drive Yards prior to the release of the standard All Terrain Armored Transport.
Sometime after its formation, the Galactic Empire's ground forces utilized a model of the All Terrain Armored Transport (AT-AT). This AT-AT was pitted against rebels during the early rebellion against the Galactic Empire. Manufactured by Kuat Drive Yards, the AT-AT was the successor of the All Terrain Tactical Enforcer (AT-TE) that saw use during the Clone Wars. The Imperial AT-AT was armed with two heavy laser cannon turrets, four anti-personnel blasters, and a dorsal twin laser turret at the rear. A Gozanti-class cruiser was capable of carrying two models of this AT-AT variant. A single walker was operated by two AT-AT drivers, who piloted the machinery alongside an optional vehicle commander.
A walker was manned by two AT-AT pilots based in the cockpit.
Many commanders placed the AT-AT at the forefront of battle, though some sent All Terrain Defense Pods (AT-DPs) to operate alongside the hulking combat walker The Imperial Grand Admiral Thrawn had his AT-AT walkers flanked by Imperial Troop Transports and stormtroopers.
The all-terrain vehicle was larger than the later AT-AT model used during the Galactic Civil War, which measured twenty- and twenty-two point five meters in length and height respectively. However, as with the later model, its legs were attenuated as with other walkers such as the AT-TE or AT-DP, allowing the early walker model to be exploitable by lightsaber strikes and, in one instance, magnetic harpoons that tripped the entire walker and exposed its vulnerable neck to laser cannon or heavy projectile cannon fire that severely damaged the vehicle.
The AT-AT walker was developed from the Clone Wars-era AT-TE for use in the Imperial Army, the ground forces of the Galactic Empire. The AT-AT constituted a far more imposing example of walker technology than its predecessor; it featured long legs that lifted the narrow body of the vehicle which towered over the AT-TE as well as the planet Kashyyyk's deep rivers, superseding the Clone Wars vehicle's six stubby legs whose movements were hindered by obstacles of a comparable height. The AT-AT was in service by the time of the Invasion of Mon Cala in 18 BBY.
Cal Kestis infiltrates an AT-AT's troop compartment.
In 14 BBY, several AT-ATs were stationed on Kashyyyk and were deployed to assist in defending an Imperial Refinery against Saw Gerrera and his Partisans. However, one of them was hijacked by the Jedi Padawan Cal Kestis, who used it to help Partisans capture a landing area by eliminating imperial forces on the way, but the AT-AT fell after Kestis used it to take down a Zeta-class Heavy Cargo Shuttle, which hit the AT-AT while falling.
In 4 BBY, Agent Kallus of the Imperial Security Bureau led three AT-AT walkers on an assault on the desert planet of Seelos against the Spectres. The rebel group was meeting with the exiled clone officers Rex, Wolffe, and Gregor, aboard their modified All Terrain Tactical Enforcer. Ultimately, all the Imperial walkers were lost to the rebels, and one of them was later repurposed by the clones as Joopa Base, their mobile camp.
A Gozanti-class cruiser deploys two AT-ATs to patrol the Lothal landing platform.
AT-ATs were used again in 3 BBY against the Spectres, when Princess Leia Organa arrived on the planet to give the Ghosts crew three Sphyrna-class Hammerhead corvettes. Two walkers were deployed to patrol the transports' landing platform, which were formally on Lothal to offer supplies to citizens impacted by the rebel efforts. When the rebels tried to steal the corvettes, the Ghost started firing on the AT-ATs. Four proton torpedos were not powerful enough to destroy one of the walkers, and it was necessary for Kanan Jarrus to use his lightsaber to cut its legs, toppling it. The second one was knocked down by the engines of the last corvette, piloted by Ryder Azadi.
In 2 BBY, Lieutenant Yogar Lyste deployed two AT-AT walkers, Walker 271 and Walker 414, to combat an attack on the east gate of the Imperial Armory Complex by members of the Lothal resistance group led by Ryzder Azadi. The rebels Kanan, Ezra Bridger, and Chopper escaped in the stolen AT-DP Walker 216. However, Grand Admiral Thrawn realized that the rebels had hijacked the AT-DP walker and ordered his AT-ATs to crush them. One of the AT-AT walkers proceeded to crush the AT-DP under its heavy body but the rebels managed to use their lightsabers to cut their way aboard. Morad Sumar also fired a rocket which hit one of the walker's legs. After knocking out the AT-AT pilots, the two climbed out and escaped with Ryder's cell into the wilderness.
AT-ATs shifted their cockpits upwards to take down the airborne Bendu
Thrawn then deployed six of these during the battle on Atollon. Jarrus destroyed one with his lightsaber. The Force wielder Bendu then destroyed three of the AT-AT walkers, though the last two were able to shoot him down from the sky.
The walkers were later used by Governor Arihnda Pryce on Lothal during the rescue of Hera Syndulla. As Kanan Jarrus and Hera Syndulla were about to be picked up by Bridger and Sabine Wren atop of the Lothal City fuel depot, two AT-ATs approached, and were commanded by Pryce to open fire on the fuel pods. An AT-AT pilot questioned this, referring to the highly volatile fuel contained within the pods. Despite this, Pryce insisted upon her orders; the walkers fired, causing an explosion, thus forcing Jarrus to use the Force in an effort to save the other rebels. In sacrifice, the Jedi pushed Syndulla into Bridger and Wren's awaiting gunship, preventing the harm of others as he himself was consumed in the ensuing flames.
In the aftermath of this incident, Grand Admiral Thrawn viewed Pryce's actions as a mistake as it destroyed the Empire's entire fuel supply on Lothal for his TIE Defender project.
Before the Liberation of Lothal, the Ghost visited the walker Joopa Base on Seelos.
The design of the All Terrain Armored Transport in Star Wars Rebels is taken from early illustrations produced for Star Wars: Episode V The Empire Strikes Back by Joe Johnston and Ralph McQuarrie. In particular, the early-1978 Johnston sketch and McQuarrie's early-1982 illustration.
