All Terrain Armored Transport

"They're the most heavily armored ground vehicles in the Imperial Army.''" "''...so what you're saying is that you have a thorough knowledge of just how screwed we are."

- Thane Kyrell and Yendor, just before the Battle of Hoth

The All Terrain Armored Transport (AT-AT) was a four-legged combat walker used by the ground forces of the Galactic Empire. With the Imperial-class Star Destroyer and the TIE/ln space superiority starfighter, it was one of the most famous symbols of the Empire's military might.

Description
"Watch out kid, this thing handles like a drunken bantha."

- Han Solo, to Luke Skywalker while piloting an AT-AT

The All Terrain Armored Transport was an imposing, heavily armoured, quadrupedal combat walker that stood 22.5 meters tall and could move 60 kph. Due to their impressive appearance, it was used as much for psychological effect as for tactical reasons. Additionally, it also served as transports for combat personnel. The vehicle's cockpit and sensor array were located in the "command pod" or "head" part of the walker, which also carried spot lights and the main armaments: dual Piperii-Cerlurn R-90C medium blasters located on the sides or "temples," and a pair of heavier Taim & Bak MS-1 heavy blaster cannons fitted on the "chin." Inside the cockpit stood an AT-AT commander behind two AT-AT pilots who controlled the walker's movement. AT-AT pilots and personnel wore specialized suits in case the walker's pressurized cockpit was smashed open in hostile environments. The armor plating of the AT-AT was impervious to blaster bolts but not heavy weapons like proton torpedoes, as early models of the AT-AT could take 4 proton torpedoes, and an AT-TE's mass driver cannon produced no visible damage to the walker's head and body; however, the legs on the early models could be damaged by missile launchers, forcing it into a limp, and could not withstand 4 proton bombs. However, the neck and joints were weak spots and could be damaged by blaster cannons and other heavy weaponry. The entire walker was vulnerable to other AT-AT fire, if one happened to be hijacked and turned against the other.

Connecting the "head" to the "body" was what was dubbed the "tunnel," which would lead to a troop compartment capable of ferrying numerous soldiers, along with a vehicle bay at the walker's rear that held five 74-Z speeder bikes. The main, rectangular troop hatch was located in the middle of the walker's side, two smaller escape hatches were located both to the main hatch's immediate left and right, and the auxiliary hatch was located in the walker's underside. The walker's tail end consisted of filtered atmosphere intakes on its upper part, while a blaster cannon energizer was located within. At the bottom of the behemoth was the walker's fuel slug tank, which had a reputation of being dangerous. The walker's four legs were aided with the assistance of ankle drive motors, while inside the giant footpads were several terrain scanners.

There was a more heavily-armored variant with a darker color scheme called an Elite AT-AT. There was also a slicker variant with more slanted sides and a smaller "head" called the AT-ACT. At least four of these walkers were present during the Battle of Scarif.

Age of the Empire
"I heard of these. Imperial armored transports. Giant four-legged things that were used to keep the peace on conquered worlds."

- Scoggan, to Davjan Igo upon entering the ruins of an AT-AT

The AT-AT walker was developed for use in the Imperial Army, the ground forces of the Galactic Empire. It was the successor of the All Terrain Tactical Enforcer that saw use during the Clone Wars, although it constituted a far more imposing example of walker technology. Heavily armored and awe-inducing, the AT-AT positioned itself as the standard of Imperial firepower on the battlefield.

In 4 BBY, the Imperial Security Bureau Agent Kallus led three developmental AT-AT walkers on an assault on the desert planet of Seelos against the Spectres and three retired clone officers aboard an AT-TE. These early AT-AT's were in fact larger than what would later be used by the Galactic Empire, and carried at least 1 614-AvA speeder bike in its vehicle bay. The 614-AvA speeder bikes would later be replaced with the newer 74-Z speeder bikes coming into production.

AT-ATs were used again in 3 BBY against the Spectres, when Princess Leia Organa arrived on the planet to give the Ghost's crew three 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 Hammerhead, 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 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.

Thrawn then deployed four of these during the battle on Atollon. Jedi survivor Kanan Jarrus then destroyed one with his lightsaber. The Force wielder, the Bendu then destroyed two of the AT-AT walkers. However, the last one was able to shoot Bendu down from the sky.

Galactic Civil War
"That armor's too strong for blasters. Rogue group, use your harpoons and tow cables. Go for the legs; it might be our only chance of stopping them."

- Luke Skywalker, during the Battle of Hoth

Following the Battle of Yavin, the Alliance to Restore the Republic stole a number of AT-ATs and provided them to Saponza's Gang.

During the Rebel assault on the Imperial weapons factory moon of Cymoon 1, a group of Rebels led by Han Solo and Leia Organa stole an AT-AT from Weapons Factory Alpha. They used the walker to escape from the factory after they sabotaged its main power core to explode. During their escape, Solo fired a shot that nearly killed the Sith Lord Darth Vader, using the AT-AT's powerful quad laser cannons. Soon after, Vader managed to overtake the Rebels in their escape and cut down the massive walker's back-left leg. The AT-AT fell tremendously and its passengers barely managed to escape the wreckage; before fleeing Cymoon 1 entirely for the safety of the Alliance Fleet

During the Battle of Hoth, General Maximillian Veers led a squadron of at least five AT-ATs on the icy fields of Hoth to knock out the shield generator that protected Echo Base, the Rebel headquarters. The triumph of Veers' squadron allowed the Imperials to invade Echo Base and rout the Rebels, striking a major blow in the war. However, the battle also revealed that the AT-ATs could be toppled by a cable wrapped around their legs. Although that weakness had been used effectively by the Alliance on Hoth, the Empire continued to use these mechanical behemoths in the later stages of the war, employing them in several skirmishes on Tatooine.

In 5 ABY, the closing year of the Galactic Civil War, at least one AT-AT walker was stationed at Camp Sardo on the planet Kashyyyk. During the Liberation of Kyshyyyk, several Wookiee guerrilla fighters, including Kirratha, hijacked the AT-AT walker and threw out the crew. Shortly later, AT-ATs were deployed against New Republic forces during the Battle of Jakku.

Rise of the First Order
Decades after the war's conclusion, a young scavenger named Rey used one of the downed AT-ATs, designated Hellhound Two, as her home on Jakku.

Behind the scenes
The names "All Terrain Armored Transport" or "AT-AT" is never spoken in any of the films. Instead, the machines are referred to as "Imperial walkers." The AT-ATs used in The Empire Strikes Back and the brief appearance in Return of the Jedi were created with the use of stop-motion animation.

Initially, the Empire was to attack the Rebel base on Hoth using tanks. Joe Johnston created many designs of these vehicles, one of which was the basis for the HAVw A6 Juggernaut that appeared in Star Wars: Episode III Revenge of the Sith and the HAVw A5 Juggernaut in Star Wars Legends, and the tanks themselves were to be portrayed by remote controlled vehicles. However, Dennis Muren and Joe Johnston convinced George Lucas to use stop motion instead, which later eventually lead to the abandonment of the tank design. In the DVD commentary to The Empire Strikes Back, George Lucas explains that he got the idea of the AT-AT from the massive tripods from H.G. Wells' 1898 novel The War of the Worlds. Though it is popularly believed that dock machinery was the inspiration for the AT-AT, Phil Tippett has said otherwise, recalling that it was based on the prehistoric mammal Baluchitherium. The AT-ATs featured in Star Wars Rebels series are different models than the ones in the Star Wars films, inspired by the early concept arts drawn by Ralph McQuarrie during the production of The Empire Strikes Back.

Non-Canon appearances

 * Epic Yarns: The Empire Strikes Back
 * LEGO Star Wars: The Force Awakens
 * LEGO Star Wars: The Force Awakens
 * LEGO Star Wars: The Force Awakens
 * LEGO Star Wars: The Force Awakens
 * LEGO Star Wars: The Force Awakens
 * LEGO Star Wars: The Force Awakens