Imperial I-class Star Destroyer

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An Imperial II-class Star Destroyer
Imperial I-class Star Destroyer Specifications
Manufacturer Kuat Drive Yards
Product Line Star Destroyers
Model Imperial I-class Star Destroyer
Class Capital ship
Length 1,609 meters
Max Acceleration 2,300+ G
Engine Unit(s) KDY Destroyer Ion Engine (3)
Cygnus Spaceworks Gemon-4 Ion Engine (4)
Power Plant SFS I-a2b Solar Ionization Reactor
Hyperdrive Class 2
Cargo Capacity

9,700 infantry
72 TIE fighters
8 T-4a Lambda-class shuttles
15 Gamma-Class ATR-6 assault transports
5 Assault Gunboats
20 AT-AT walkers
30 AT-ST walkers
A variable number of Skipray Blastboats
Delta-Class DX-9 stormtrooper transports
Y85 Titan dropships
Sentinel-class landing craft

Crew 37,000
Passengers 1800
Armament 60 Taim and Bak XX9 turbolasers
60 Borstel NK-7 ion cannons
2 dual heavy ion cannon turrets
10 Phylon Q7 tractor beam projectors
Numerous lesser weapons
Systems LeGrange targeting computers
SFS S-s3a tachyon detection scanner
Shields Om-Thaim generators (2)

Galactic Empire, Imperial Remnant, New Republic

The Imperial I-class Star Destroyer was a monumental starship designed by Lira Wessex and built by Kuat Drive Yards. The ship began development as the Imperator-class under the Galactic Republic, but became infamous as the prime enforcer of Imperial rule.

They were massive, powerful ships, capable of laying waste to entire worlds (provided those worlds did not have planetary deflector shields). It was belonged to the Star Destroyer family of warship, exemplified by its dagger/arrowhead design. A single Imperial-class vessel cost the Empire at least 3,880,000,000 Imperial credits—the equivalent of several star systems' annual economic output.

This entry covers the definitive version of the type, the Imperial-class Star Destroyer. It was the premier starship class in the Imperial Starfleet. All known variants were 1,609 meters long (approximately one mile) and had three large and four small engines capable of accelerating the ship with a force of several thousand g.

Star Destroyers of this class took part in the three major engagements that towards the end of the Galactic Civil War; the Battle of Yavin, the Battle of Hoth, and the Battle of Endor. A progenitor of the Imperator/Imperial class, the Acclamator-class assault transport, saw service during the early days of the Clone Wars; another progenitor, the Venator-class Star Destroyer, was in use by the war's end.

Technical information

Crew Requirements

Star Destroyer Crew Breakdown chartAccording to officially available statistics, ‘‘Imperial’’-class Star Destroyers have at least 37,000 officers and crew. Counting the stormtrooper complement (one "division" or "legion", 9,700 men) would total 46,700. This would include a stormtrooper detachment, fighter pilots, and support craft pilots.

When serving as a flagship, 900 additional personnel were stationed onboard. The Star Destroyer could accommodate up to 1,800 passengers.

For those vessels that entered New Republic service, the New Republic reduced the crew requirements by 8,000, to about 28,000 men.

The crew requirements of the Imperator are extraordinarily high. New Republic ships of the closest size tend to have a small fraction of the crew. It is also interesting to note the ISD's high ratio (over 7:1) between full and skeleton complement—a more usual ratio seems to be 4:1 or 5:1 in large vessels.

Possible reasons include:

  • Large crew requirements enabled ongoing, intensive recruitment
  • Multiple or redundant onboard crews
  • Allowed for easy placement of ISB or COMPNOR agents
  • The ISD's six-year endurance requirement passes a certain limit beyond which maintenance requirements greatly increase; large crews of technicians are thus embarked.
  • Inferior automation compared to that of latter warships, especially those fielded by the New Republic.

Bridge Tower

The command bridge tower of the Imperial-class Star Destroyer was massive. The command bridge of the ship was much like that of the Executor The difference between the deck and the ceiling was three to four meters for the command walkways and one and a half meters more for the control pits. The total number of decks on the bridge tower was somewhere between 20 to 30, with the average spacing of 3 meters. At a few areas there were portals that appeared at intervals halfway between the main decks. These corresponded to inhabited chambers, rooms, or shafts spanning more than one level.

Sublight propulsion

The ion engines of an ISD at full thrustFor sublight propulsion, the Imperial class relied on an array of three primary ion engines produced by KDY specifically for the vessels. For emergency situations requiring additional thrust, the Imperial class could use its four Gemon 4 ion engines.

Main Battery

The first flight of ships (generally known as the Imperator or Imperial I) possessed a main battery of 12 heavy turbolasers and 4 heavy ion cannon for disabling enemy warships. Those heavy guns were set in twin mounts flanking the tower structure. The second flight of ships (generally known as the Imperial II) possessed a main battery of 64 heavy turbolasers in eight octuple mounts flanking the tower structure. Furthermore, each brim notch in the trench could be fitted with a quadruple heavy turbolaser.

Strangely, the Imperials in either subclass did not choose to give their turrets superfiring ability from a level position, either by superelevating the after turrets or merely by spacing them out over a longer distance and letting the natural wedge shape provide the ability. Perhaps superelevation proved impossible with the immense recoils involved (official estimates imply yields so great that the momentum of the fired bolts, and the associated recoil, would be comparable to a large asteroid impact), and perhaps spacing the turrets out proved too great a compromise in terms of power distribution.

Secondary Weapons

Numerous smaller guns were mounted around the ship to ward off attacks against lesser ships not capable of being targeted by the main battery. They varied in size; some were designed as point-defense cannon to destroy incoming missiles and starfighters while others engaged lesser capital ships. Several examples have been explicitly equipped with proton torpedoes, most notably NRS Emancipator (ex-Accusor) and Chimaera. However, it is not known whether or not they are refit additions or not.

The Star Destroyer's weapons are designed to make the vessel a long range assault ship. The weapons systems are not very capable of targeting at point-blank range, a weakness exploited by the Rebel fleet at the Battle of Endor.

Axial Turrets

Three triple-gun turrets were mounted on the ridge of the ship, just forward of the lowest, forwardmost, terrace of the dorsal superstructure.

Hangar Defences

Mounted just beyond the forward tip of the attack hangar (see fighter compliment), were two large ventral turbolasers, which sat near the corners of the massive hangar. The primary function of the turbolasers was to defend the vulnerable docking facilities, but could also be used for planetary bombardment.


There were entire planets that, throughout their history, did not expend as much power as an Imperial-class ship did in one hyperspace jump. A massive solar ionization reactor bulged from the ventral spine, using its fires to fuel the ship.

Fighter Compliment

Each ship carried a wing of 72 Imperial TIE fighters, generally of mixed load out of space-superiority fighters, bombers and reconnaissance spacecraft. These fighters usually consisted of 48 TIE/In fighters, 12 TIE bombers, and 12 TIE boarding craft. At least one ship, NRS Rebel Dream, ex-Tyrant, featured an enlarged hangar bay, but it is unknown if a greater number of fighters were carried.

The attack hangar was guarded by a set of armored doors. TIE fighter service and refueling bays, and TIE launch hangars surround the main hangar. TIEs were launched from cycling racks and pilots boarded from overhead gantries and were released into space as they disengaged from the front position in the racks. Returning fighters landed in separate hangars and then were guided by small tractor beams into receiver-carriers. The receivers carried the TIE to a debarkation station where the pilot would exit. Once moved through the transfer tunnels to a launch hangar, the fighter could be serviced and refueled in a separate bay. In the hangar the TIEs were cycled through a launch rack and ready for the next launch.

The small forward hangar was for shuttle craft carrying high-ranking officials. The forward hangar was also used as a back-up to the main hangar.

Ground Assault Capability

Several thousand troops were also stationed aboard along with a prefabricated base for rapid subjugation of rebellious territories. The ships also carried massive war vehicles including the AT-ATs and AT-ST walkers. According to some sources, the Imperial-class Star Destroyer also carried support craft and dropships such as the Y85 Titan Dropship and the Sentinel-class Landing Craft. The ship could also use TIE Fighters and orbital bombardment to support any surface action.

Areas of service

Imperial service

Imperial-class Star Destroyers had a distinguished career in the Imperial Starfleet, where they symbolized the Empire's military might (for better or worse). According to official records, over 25,000 were procured. Many were destroyed in the fratricidal warfare that consumed the Empire after the death of Emperor Palpatine at Endor while others defected or were captured.

Within Sector-level and many Regional-level fleets, the ISD serves a central role, being the flagship of the unit known as the "Battle Squadron." It has also been observed to operate more or less independently.

More controversial is its role on higher levels. In some reliable records as well as in several others, the ISD was shown to be a mere support ship— chasing down corvettes and providing escort to Darth Vader's Executor. Arguably it is only fit to be a support ship— at the Battle of Hoth the Rebellion's heavy ion cannon was able to easily overwhelm a Star Destroyer's shield and disable the ship. At the Battle of Endor, at least one ship was an intermediary between dreadnoughts like Executor and lesser ships like Imperial. Further information also indicates many other types of ships larger than Imperial yet smaller than Executor.

This has lead to some to conclude that there is a higher level of Fleet than Sectorial and Regional, with the ISD finally able to revert to its role as destroyer and with ships like the Executor taking the role of dreadnought. Others conclude the ships shown in these visual records are either indistinct blops or poorly drawn ISDs, that there are no intermediate ship types between ISD and the Executor and that Executors are an unusual aberration.

Foreign service

This particular class of vessel has seen extensive service in other navies, including that of the successor-state New Republic. The refits implemented by that government appeared to have involved deletion of the quadruple heavy trench guns, installation of proton torpedo launchers and use of a much smaller crew. The ability to embark planetary-assault soldiers appears to have been ignored as well (the Republic choosing to use dedicated troopships). Endurance was reduced from six years to six months; New Republic Defense Force doctrine operates ships on relatively short patrols before returning to base. The Hapan Cluster was able to seize some vessels when the Galactic Empire prepared to abandon their fleet yards near Hapan space.

Despite their stellar qualities, the ‘‘Imperial’’-class Star Destroyer, to many, was apparently too much of a symbol of Imperial might. The New Republic chose to procure Mon Calamari Star Cruisers instead; what few Imperial-class Star Destroyers they possessed may have been from defectors or captured. Descendants of the Victory-class Star Destroyer were procured in quantity however; as the Victory was a symbol of the Old Republic's military machine it may have been more politically acceptable.

Private service

One Star Destroyer operated in private hands, the Errant Venture (ex-Virulence), captained by Booster Terrik. It was captured several years after the Battle of Endor but was in poor condition for many years owing to the great cost of maintaining such a large vessel. In addition, she was stripped of the vast majority of her armament: only ten (presumably light) turbolasers were permitted, and even those were not always functional. Years later, she received a comprehensive refit in exchange for use in a New Republic special-operations raid on an Imperial base. The most notable part of this refit was a deep red paint job instead of the classic Imperial white. While Captain Terrik was not permitted to keep all of his weapons after the operation, they were reinstated when the Yuuzhan Vong invasion occurred. During the Yuuzhan Vong invasion, she served as a temporary Jedi sanctuary and also as squadron flagship. No other private Imperial-class Star Destroyers are known to exist.

Behind the Scenes

  • There has been some disagreement over the name of the class. Early production documentation shows a ship named Imperator, produced at the Gyndine shipyards. However, this ship is much smaller (on the order of 700 meters) than the ship shown in the movies as many designs were greatly upscaled shortly before production began. Some argue that the intent was to have the ship (and class) named Imperator and that "Imperial"— being the adjective form of "Empire"— is a rather odd name for a ship. Others argue that the ~700 meter ship represents a distinct class and that Imperial is the true name— regardless of how silly it may sound— as it is used in many of the Expanded Universe books. The Star Wars Incredible Cross Sections: Episode III eventually put the debate to rest by stating that while the class was originally named Imperator, it was renamed Imperial at some point after the Great Jedi Purge.
  • "Imperator" is Latin and was used as a title for "An army commander in the Roman Republic". Later, during the Roman Empire, it became a title worn by the Emperors and signified "The supreme power of the Roman emperor".
  • The RPG has also made a statistic set for the two subclasses, but they seem highly inaccurate in both numbers and magnitude when compared to the film - the highest canon.
  • Imperial-class Star Destroyers have featured prominently in many Star Wars computer games. However, they have generally been "toned-down" to allow the player some chance of defeating them with a starfighter.
  • Imperial-class Star Destroyers have also been referred to as 'cruisers'. This is probably due to one of their abilities, which is being able to operate independently and not just as part of a group.

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