A typical Imperial Class Star Destroyer
An Imperial Star Destroyer is a type of fictional starship from the Star Wars universe. Designed and built by Kuat Drive Yards for the Galactic Empire, they are massive, powerful ships, which are capable of laying waste to entire worlds (provided those worlds do not have planetary deflector shields). It is generally said to belong to the Star Destroyer family of warship, exemplified by its dagger/arrowhead (or, derisively, cheese-wedge) design.
Imperial Star Destroyers are seen in all three movies of the original trilogy. The progenitor of the Star Destroyer, the Acclamator, was seen in the second movie, Attack of the Clones.
This document covers the definitive version of the type, the Imperial Star Destroyer, which is sometimes called either Imperial-class or Imperator-class. It is the premier class of medium starship in the Imperial Starfleet in the Star Wars universe. All known variants are 1,609 meters long (approximately one mile) and have three large and four small engines capable of accelerating the ship with a force of several thousand g.
According to officially available statistics, Imperial Star Destroyers have at least 37000 officers and crew. Counting the stormtrooper complement (one "division" or "legion", 9700 men) would total 46700. This would include a stormtrooper detachment, fighter pilots, and support craft pilots.
For those vessels that entered New Republic service, the New Republic reduced the crew requirements by 8000, to about 28000 men.
By SW standards, 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 Star Wars vessels.
Possible reasons include:
- Multiple onboard crews, analogous to real-world SSBNs (though in this case, the alternate crews are carried onboard, not in port)
- 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.
From film canon and model observations, the first flight of ships (generally known as the Imperator-I 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 Imperator-II or 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. Several official estimates (most notably, Star Wars Attack of the Clones: Incredible Cross Sections) indicate that each heavy turbolaser possesses more firepower than the combined historical nuclear arsenal of Earth. However, as these numbers have never been directly demonstrated in the movies, there is some disagreement as to their validity.
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.
As an aside, 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.
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-HIMS Accusor) and HIMS 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 assualt 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.
Fighters & Passengers
Each ship carried a wing of 72 Imperial TIE starfighters, generally of mixed loadout of space-superiority fighters, bombers and reconnaissance spacecraft. At least one ship, NRS Rebel Dream, featured an enlarged hangar bay, but it is unknown if a greater number of fighters were carried. Several thousand troops were also stationed aboard along with a prefabricated base for rapid submission of rebellious territories. AT-AT and AT-ST walkers were carried but they did not appear to carry specialized air-support craft, relying on TIE Fighters and orbital bombardment to support any surface action.
Imperial 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 literature, over 24,000 were procured; some fans argue for lesser (or much greater) numbers. Some fan estimates range as high as 180,000 ships. 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.
The ISD and its Place in the Imperial Fleet
Within Sectors and many Regional level fleets depicted in most of the Extended Universe, 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 the its role on higher levels. In the classic trilogy as well as in several comics, 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 -- in The Empire Strikes Back 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 in the Expanded Universe (especially Dark Empire) 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 Dark Empire 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 abberation.
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 in Hapan space.
Despite their stellar qualities, the Imperial Star Destroyer, to many, was apparently too much of a symbol of Imperial might. The New Republic chose to procure Mon Calamari cruisers instead; what few Imperial Star Destroyers they possessed may have been from defectors or captured. Descendants of the Victory 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.
One Star Destroyer operates in private hands, the Errant Venture (ex-HIMS 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 Vong invasion, she served as a temporary Jedi sanctuary and also as squadron flagship. No other private Star Destroyers are known to exist.
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.
List of Star Destroyers
SWTC (http://www.theforce.net/swtc/isdlist.html) has a fairly extensive list of ISDs.
Shield or Sensor Globes
See Super Star Destroyer