Walker (Star Wars)

Joe Johnston's original design for the Empire's war machines was a giant, multi-wheeled vehicle; this design later became the "Juggernaut" in West End Games' roleplaying material, and the design was reworked into the clone turbo tank for Star Wars: Episode III – Revenge of the Sith.[3] Johnston said Lucas wanted the walkers to look like anthropomorphic walking tanks to make them frightening.[4]

For The Empire Strikes Back, however, the final design was a four-legged walker. Inspiration for the AT-AT came from Paraceratherium, an extinct genus of rhinoceros and the largest land mammal in history.[5] George Lucas later dismissed claims that the AT-AT design was inspired by container cranes at the Port of Oakland (across San Francisco Bay from ILM's San Rafael offices), calling it a "myth"; animator Phil Tippett told the San Francisco Chronicle the same thing.[6]

ILM created models ranging from six to fifty centimetres (2–20 inches) in height.[7] ILM filmed the AT-ATs using stop-motion animation against matte paintings created by Michael Pangrazio because attempts at compositing miniature footage against live-action background footage yielded mediocre results.[7] Additionally, ILM studied elephants to determine the best way to animate the four-legged AT-ATs.[7] Although the stop-motion animation style gave the AT-ATs a jerky, "staccato-like" effect on film, ILM found this movement acceptable because of the AT-ATs' mechanical nature.[8]

The sound of the AT-AT walking was created by sound designer Ben Burtt by using the sound of an Industrial Sheet Metal Stamper.

Attraction at Disney's Hollywood Studios

Dialog in National Public Radio's adaptation of The Empire Strikes Back says that AT-ATs "look like animals"; the character goes on to describe the vehicles as carrying "extremely heavy armor and armaments". The AT-AT, designed to favor "fear over function", can carry up to five speeder bikes and 40 Imperial stormtroopers.[1] The head/cockpit armament consists of two side-mounted medium blaster cannons and two chin-mounted heavy laser cannons. It is manned by two AT-AT Drivers, which are combat drivers specialized in operating the Imperial Army's AT-AT walkers, wore distinct battle armour, similar in design to that of a modified basic Stormtrooper. The drivers operated the walker's movement and firing controls, and are overseen by a commander who sits behind them in the cockpit.[9]

Manufactured by Kuat Drive Yards, Expanded Universe sources describe the AT-AT as being either 15 metres (49 ft) or 22.5 metres (74 ft) tall.[1][9][10] The AT-AT's rate of stride is not fast, but this fact is mitigated by the immense height of its legs. They can outrun opponents that underestimate AT-AT walking speed, while their neck can pivot quickly enough to bring their heavy weaponry to bear against even fast-moving craft like snowspeeders. Their blasters and laser cannons do not have a high rate of fire, but the shots are powerful enough to destroy most small targets in one to two shots. Their armor is resistant to most standard blaster weapons; however, the "neck" column of the walker holds no such invulnerability and, if shot, can cause the entire walker to be destroyed.

The AT-AT is the primary assault vehicle during the Battle of Hoth, first depicted in The Empire Strikes Back. In the film, the squadron of AT-ATs, lead by General Maximilian Veers, are responsible for destroying the shield generator protecting the Rebel headquarters, taking out soldiers, artillery batteries, and snowspeeders in the process. Luke Skywalker, realizing that the walkers are all but impervious to artillery and snowspeeder blaster fire, orders his squadron's snowspeeders to entangle their legs with tow cables, a trick he remembered using on Tatooine to rein in hard-to-control farm animals. Wedge Antilles and his gunner Wes Janson successfully bring down an AT-AT using the tow cable: shortly after, another snowspeeder scores a direct hit on the fallen AT-AT's neck, causing a huge explosion. Skywalker, after being shot down and narrowly escaping his stricken snowspeeder before it is crushed beneath the AT-AT's leg, used his hoist cable to latch upon that AT-AT's underside, with a slash of his Lightsaber cutting away a panel so he can toss a thermal detonator inside, causing a series of internal explosions culminating with the cockpit and the walker toppling over. In the novelization of The Empire Strikes Back, General Veers' AT-AT is destroyed when its cockpit is rammed by a snowspeeder piloted by Derek "Hobbie" Klivian, however this never made it into the final cut of the film.

An AT-AT makes a brief appearance in Return of the Jedi; one walks up alongside a landing platform on Endor to deliver Luke to Darth Vader.

The first appearance of an AT-AT in the Star Wars Rebels TV series occurs in the second-season episode "Relics of the Old Republic", when Agent Kallus unsuccessfully confronts the rebels while on Seelos, with a trio of the four-legged walkers challenging Captain Rex's retired clone cohorts and their own much-modified AT-TE six-legged walker, where the rebels are hiding out. This walker is significantly bigger than those seen in the films and depicts an earlier model.

A ruined AT-AT appears in Star Wars: The Force Awakens as the makeshift home of the scavenger Rey on the planet Jakku.

The First Order uses an updated model of the AT-AT during the Battle of Crait at the end of Star Wars: The Last Jedi alongside a similar but larger walker called the AT-M6.

The theme park attraction Star Wars: Rise of the Resistance, set after The Last Jedi, features two full-sized AT-ATs in a hangar bay. These walkers, while mostly static, can move their cannons to allow for a scene in which the walker's drivers spot the ride vehicles and fire at them.

A single AT-ST makes a brief appearance in The Empire Strikes Back alongside the larger AT-ATs during the Battle of Hoth. The AT-ST was meant to have more screen time; however, one scene depicting a snowspeeder shooting at the AT-ST model was ruined when the set's background shifted.[13]

For Return of the Jedi, ILM made the AT-ST design more detailed.[13] Numerous models were created, including a full-sized AT-ST for on-location shooting.[13] Director Richard Marquand and producer Robert Watts had cameos as AT-ST operators for the scene in which Chewbacca (Peter Mayhew) and a pair of Ewoks commandeer an AT-ST.[13]

Lee Seiler sued Lucasfilm in the mid-1980s, claiming that the AT-ST infringed on his copyright on what he called a "Garthian Strider", which he said he created in 1976 or 1977. The case was dismissed with the court noting that not only did Seiler not produce the supposed drawings at trial, but that the copyright came one year after The Empire Strikes Back debuted.[14]

Star Wars guidebooks describe the AT-ST as a "reconnaissance or defensive vehicle [that] is lightweight and built for speed".[12] Their agility allows them to defend the larger slower AT-ATs or support other Imperial ground forces.[12][15] Two AT-STs, with their legs folded up, can be carried inside the cargo hold of an AT-AT. AT-STs are 8.6 metres (28 ft) tall (although some sources describe them as 7 metres or 23 feet)[12] and seat a pilot and co-pilot.[15] AT-STs are armed with laser cannons on the "chin" and sides, feet claws for destroying small defenses, and side-mounted concussion missile launchers.[16]

In The Empire Strikes Back, an AT-ST scouts for and supports the slower AT-ATs during the Battle of Hoth. Video games recreating the Battle of Hoth feature numerous AT-STs which are vulnerable to snowspeeder blasters unlike the larger AT-ATs. During the ground skirmish of the Battle of Endor in Return of the Jedi, after initially taking heavy casualties from four AT-STs, the protagonists and the local Ewok tribes destroy several AT-STs and commandeer another one; the AT-ST's precariously balanced nature proves highly vulnerable to the Ewoks' primitive booby traps. Their armor is also significantly weaker than that of the AT-AT's: their own lasers proved sufficient to completely destroy one, and another one was crushed by two large tree trunks launched against it.

In the Expanded Universe, AT-STs are often featured in Imperial attack forces.[16] Some more advanced Imperial walker designs have been influenced by the AT-ST.[17] Video games such as Star Wars: Rogue Squadron and Shadows of the Empire (in a much expanded Battle of Hoth) include numerous AT-STs, and these can be destroyed by direct shooting from the player's craft, in contrast to the heavily armored AT-ATs which have to be tripped by tow cables. AT-STs are also player-controllable units in several real-time strategy games.

The so-named "All Terrain Defense Pod" (AT-DP) depicted in Star Wars Rebels was used by the Empire on Lothal, Ezra Bridger's homeworld, to enforce their will against the planet's inhabitants during the first season of the series. It is stated as being among the fastest-moving "walkers" of any of the AT-ST variants, and is only lightly armed with a single, forward-aimed energy cannon.[18]

Conceived by Ryan Church as a predecessor to the AT-AT, the AT-TE's animation for Attack of the Clones was supervised by Rob Coleman.[19] Tom St. Amand, who worked on the AT-AT scenes in The Empire Strikes Back, provided his experience to create a similar appearance for the AT-TE.[19]

AT-TEs are depicted as assault vehicles that appear at the Battle of Geonosis, as depicted in Attack of the Clones and various Clone Wars media. It has magnetic feet, which allows it to scale steep embankments if they are magnetic, like the mesa on Teth in Star Wars: The Clone Wars. The low profile, six legs and overall flexibility made it vulnerable to IEDs and reduced its acceleration and maximum speed, but lowered its center of gravity closer to the surface it was traversing, traverse speed, mobility and stability; moreover, its low speed allows it to walk through energy shields.[20][21] The vehicles are well-armed with laser turrets, a powerful mass driver cannon, and protected by heavy electromagnetic armor.[20][21] AT-TEs are manufactured by Rothana Heavy Engineering, a subdivision of Kuat Drive Yards (who manufacture many of the other walkers).[22][23] AT-TEs have the distinct tactical advantage, common among many of the Old Republic's larger walkers, of being able to be carried into combat by LAAT/C dropships. This allows their swift deployment to the battlefront from distant landing zones and ground bases.[24] In any case, a well-deployed and utilized AT-TE would win in a battle against an AT-AT (as it did on Seelos, in the Star Wars Rebels second season episode Relics of the Old Republic)

Utilized by the Republic, Empire and First Order

• All Terrain Attack Pod (AT-AP): Featured in Revenge of the Sith and Clone Wars media, as a variation of the AT-PT. Alex Jaeger designed the AT-AP per Lucas' request to "diversify the Clone armor".[26][27] Nicknamed the "sniper tank", the AT-AP features a variety of artillery weapons, a retractable third leg for stability, and other offensive features.[26]
• All Terrain Open Transport (AT-OT): Introduced in Revenge of the Sith and other sources, is a heavily armored transport whose open design makes it vulnerable from above.[28] The AT-OT can transport 34 clone troopers, who are protected by thick armor and four laser cannons.[29] During the late stages of Revenge of the Sith's development, it was called the "Clone CAT walker".[30]
• All Terrain Recon Transports (AT-RT): Introduced in Revenge of the Sith operated by clone troopers searching for Yoda (Frank Oz) on Kashyyyk. The AT-RT is described as a precursor to the AT-ST, though it also shares similarities to the AT-PTs of the same era.[31] A scene cut from Revenge of the Sith would have shown Yoda distracting clone troopers while Chewbacca removes them from their AT-RT in a manner similar to how he obtains control of an AT-ST in Return of the Jedi.[32] AT-RT animators studied AT-ST movement to recreate part of the "original funkiness of movement" caused by the stop-animation style used in the original trilogy.[32]
• All Terrain Defense Pod (AT-DP): Introduced in Star Wars Rebels as the is a powerful predecessor of the AT-ST and has the ability to dock with flying transports, much like the AT-TE can. On Lothal, many of these chicken walkers are used for hunting the young rebellion.
• All Terrain Mobile Artillery (AT-MA): Introduced in The Force Awakens. was a model of quadruped base defense walker used by the First Order to defended Starkiller Base. While it resembled the All Terrain Armored Transport once used by the Galactic Empire in terms of size and weaponry, the AT-MA was primarily designed for defense, rather than transport or assault. Several of these walkers were deployed across the planet to protect its installations, and at least three of them were present during General Armitage Hux's speech before the destruction of the Hosnian system.[33] Several AT-MAs were portrayed in the ground vehicles storage area of a Resurgent-class Star Destroyer.[34]
• All Terrain Armoured Cargo Transport (AT-ACT): Introduced in Rogue One,[35][36] the walkers are slightly larger than the standard AT-AT, with a hollowed-out center section that can hold a cargo container. Director Gareth Edwards instructed the film's concept artists to design walkers based on their idealized memory of the AT-AT.[37] As depicted in the film, AT-ACTs appear to be easier to destroy than AT-ATs. Under sustained fire, their leg joints can be destroyed, causing the vehicle to fall, and they can be broken in half when fired upon without the cargo container in place.
• All Terrain MegaCaliber Six (AT-M6): Featured in The Last Jedi, dubbed "gorilla walkers", as a class of walking siege-artillery vehicles used by the First Order. The First Order also uses updated versions of the AT-AT and AT-ST to support and screen AT-M6 siege operations.
• All Terrain Heavy Hauler (AT-HH): Featured in The Last Jedi, utilizing many more legs than most walkers to allow it to tow heavy cargo.
• All Terrain Heavy Scout (AT-HS): A model of walker fielded by the First Order. The LEGO version of the AT-HS was based on a piece of concept art for The Last Jedi which, although canon, was ultimately not used in the final cut of the film.
• All Terrain Cold-weather Mobile Heavy Cannon (AT-CMHC): A remodeled variant of the Umbaran UMHC used by the Imperial Military. This prototype model was specialized in sub-zero temperatures.[38]

Utilized by other factions

• Umbaran mobile heavy cannon (UMHC): Used by Umbarans during the Clone Wars.[25] Later, both the Imperial Army and Alliance to Restore the Republic used them during the Galactic Civil War.[38] MHCs were heavily armored and had an articulated electromagnetic plasma cannon mounted on top of its dome-like body.

• All Terrain Personnel Transport (AT-PT): Introduced during the climax of Timothy Zahn's novel Dark Force Rising, is a two-legged, one-person vehicle designed for the Old Republic as a "personal weapons platform for ground soldiers."[39] The AT-PT is equipped with two blaster cannons, a concussion grenade launcher, and an array of sensors.[39] The AT-PT is also featured in several video games, including Star Wars: Rogue Squadron, Star Wars: Force Commander, and Star Wars: Galactic Battlegrounds.
• Mountain Terrain Armored Transport (MT-AT): Introduced in Jedi Academy Trilogy, dubbed "spider walkers", are octrupedalism specially for mountain terrain.
• All Terrain Anti-Aircraft (AT-AA): Featured in various Expanded Universe media, is a four-legged anti-aircraft vehicle used by the Galactic Empire.[40] The All Terrain Advance Raider (AT-AR) appears in Marvel Comics' Star Wars series and an All Terrain Experimental Transport (AT-XT) appears in LucasArts' Star Wars: The Clone Wars game.[41] DK Publishing's Attack of the Clones: Incredible Cross-Sections book mentions an All Terrain Heavy Enforcer.[42]