Self-Propelled Heavy Artillery

"Using this weapon against droids is a necessary evil. But what if such destructive power should be turned against living creatures? A sad thought, indeed."

- Mace Windu

The Self-Propelled Heavy Artillery (SPHA) walker was a modular artillery unit used by the Grand Army of the Republic during the Clone Wars.

Characteristics
"Their range must be greater than we thought."

- A Muun during the Battle of Muunilinst

Unlike smaller walkers, such as the AT-TE, SPHA units were unable to be carried into battle by LAAT/c gunships because of their large size and weight. Instead, they were deployed directly from landed Acclamator-class assault ships, which could carry 36 of the artillery platforms.

In battle, SPHA walkers usually received orders from ground-based command posts, which provided a less isolated and more in-touch view of the battlefield than the towering walkers. In addition, SPHA units had a complement of 20 clone troopers, which could be deployed rapidly via a dorsal troop deployment hatch. In seconds, the two squads could disembark the vehicle and secure the area immediately around the walker, providing protection from enemy infantry and other light units.

Development


Developed by Rothana Heavy Engineering, a covert subsidiary of Kuat Drive Yards, the SPHA walker was designed to fulfill the role of mobile ground-based long-range artillery support.

It complemented the two other key components of Republic military strategy&mdash;the AT-TE walker and the LAAT/i gunship. In a typical attack, the AT-TEs and LAATs would spearhead the assault, establishing a forward base and allowing heavier support forces (such as SPHA walkers) to consolidate gains and provide reinforcements.

In development of the system, engineers on Rothana essentially had to build their prototype around the requirements of the primary weapon: a large, dorsally-mounted external weapon assembly, a powerful reactor core to fulfill the weapon's high energy requirements, and all of the necessary support equipment and crew stations.

In order to save weight, designers rejected a complex turreting mechanism, instead relying on the entire walker to reposition in order to adjust for different firing coordinates. Because of the fixed weapon positioning, the turbolaser was unable to track rapidly moving targets, such as speeders or small atmospheric craft. Like other walkers, the use of articulated legs prevented the SPHA from being vulnerable to anti-repulsorlift weapons, at the cost of some mobility.

The result of this development process was a walker that possessed a very capable capital ship-class weapon, but was hampered by its low mobility. This low mobility was exacerbated by the fact that SPHA walkers were equipped with heavy armor, especially in the frontal area of the vehicle around and just below the command deck. This armor was necessary to protect the vehicle's reactor core from enemy fire, as any meltdown would cause tremendous collateral damage.

Main weapons


The SPHA walker chassis served as the basis for a number of different weapons platforms, though the best chronicled version was the turbolaser (SPHA-T) configuration. This variant's main weapon was a heavy turbolaser cannon, capable of causing extreme direct fire damage to large or slow-moving targets.

The primary disadvantage of this powerful weapon was that it was incapable of providing indirect fire support to out of sight locations, a problem remedied in other models. Another disadvantage was that the weapon could only be charged to a certain level&mdash;upon firing such shots, they had to be replaced with charged guns from the rear lines.

Some of these other variants deployed during the Clone Wars include the ion cannon (SPHA-I), anti-vehicle laser (SPHA-V), concussion missile (SPHA-C), and mass-driver models. Some of these model variations included 12 retractable antipersonnel blasters, necessitating an additional 10 gunners to the command crew of 15.

Usage
The SPHA, particularly the SPHA-T, first appeared in the Battle of Geonosis where it was instrumental in shooting down several Lucrehulk-class core ships and Hardcell-class interstellar transports.

SPHA units were used throughout the Clone Wars, seeing action in battles such as the First Battle of Cato Neimoidia, the Battle of Muunilinst (where many were destroyed by the nimble IG lancer droids), the Second Battle of Rhen Var, and the Second Battle of Tatooine. At the suggestion of Anakin Skywalker, many Venator-class Star Destroyers of the Open Circle Fleet had SPHA-T turbolaser cannons installed inside their ventral hangar bays, where they were used effectively during the Second Battle of Coruscant, especially against enemy Munificent-class star frigates. Many of these battles highlighted its strengths and weaknesses&mdash;massive firepower and range, but very poor maneuverability and speed.



The SPHA-line walkers would still see service in the early years of the Galactic Empire, until the SPMA-line was developed. Being equipped with weapons-generators equally powerful to the ones installed in the old SPHA walkers, it's reasonable to believe that the SPHA-chassis would in turn receive similar new developments as upgrades to retain its title of "Heavy Artillery". The variants equipped with projectile ordnance would also have no need for replacements, since the amount of ammunition they could carry would always exceed a smaller design.

With their intimidating size fitting the Tarkin Doctrine's policy of rule by fear, it is highly probable that some or all variants of the SPHA were still being used during the Galactic Civil War.

Appearances

 * Star Wars Episode II: Attack of the Clones
 * Star Wars: Clone Wars
 * "Chapter 1"
 * "Chapter 4"
 * "Chapter 8"
 * "Chapter 20"
 * Star Wars: Galactic Battlegrounds: Clone Campaigns
 * Hide in Plain Sight
 * Impregnable
 * Jedi: Yoda
 * Jedi Trial
 * Star Wars Episode III: Revenge of the Sith
 * Star Wars Rebellion: My Brother, My Enemy