The first four Executor-class ships were constructed in the months following the Battle of Yavin and the destruction of the first Death Star. Before the Battle of Yavin Imperial Navy engineer Lira Wessex designed these sleek, dark, immense vessels to inspire dread in any possible opponent. It is claimed that they are larger than any previously constructed warship, with the exception of the Death Star. While it is difficult to believe that this boast could hold against every warship built throughout the twenty-five thousand year history of the Galactic Republic, the colloquially nicknamed “Super Star Destroyers” dwarfed all other vessels in the fleets of the Empire and the Rebel Alliance / New Republic until the appearance of the shorter but more massive Eclipse and Sovereign classes six years after the Battle of Endor.
At their conception, the Executor-class star dreadnoughts were controversial. It seems that many important figures within the Imperial Admiralty favoured the construction of well-proven, smaller and more numerous warships. Manufacturing an Executor-class command ship reportedly costs roughly twenty times as a star destroyer, despite being well over a hundred times as massive. Lord Vader's interest in this KDY design gave its development impetus [Classic STAR WARS comics] and construction of the first ship began at the shipyards of Fondor. Among Lord Vader's secretive detractors within the Imperial Navy, several fleet admirals were quick to oppose the Executor project. As usual, the wishes of the Emperor's enforcer prevailed. After unsuccessful rebel saboutage attempts, Lord Vader took the first of these ships, the Executor, as his own flagship for coordinating the eradication of the Rebel Alliance the more personal search for his long-lost son.
In the following months the Executor-class gained recognition and proved its value as an instrument for inspiring awe and dread. The Emperor authorised the construction of additional ships of the class. Eventually the mighty command ship was regarded as the grand epitome of a newly revitalised Imperial Navy. While they never approached the abundance of the Empire's tens of thousands of common star destroyers, by the time of the Battle of Endor a large number of these vessels had entered service.
In the years following the establishment of the New Republic the number of Executor-class command ships in Imperial use dwindled as the Empire's remnants lost control of shipyards, fought amongst themselves and with the ever-growing New Republic Navy. By the time Grand Admiral Thrawn returned to rally the Imperial Navy, no ships of this size were available to him. Each had either been destroyed, captured by the New Republic, regional governments and neutral forces, or retreated to the Deep Core regions of the Empire which did not recognise Thrawn's authority. It can be assumed that Kuat Drive Yards produced these vessels and even newer classes of command ships for the New Republic Navy and its subordinate sector navies, once the new government consolidated its power in the Core sectors.
Unfortunately the first President of the New Republic, Mon Mothma, ordered a halt to the production and use of these grand warships at some time during her seven-year tenure. The strategic imprudence of this public-relations gesture was brutally exposed several years later when the New Republic forces were shown to be badly outgunned in the Black Fleet Crisis. Whether Princess Leia Organa-Solo, as Mothma's successor, eventually learned from and rectified the mistake is unclear at this time. General Cracken's formation of a special acquisitions team to retrieve the lost Guardian a year after the Koornacht Crisis, and the fact that New Republic warships supporting the operation used ion cannons only, indicates a sensible change of policy.
The immense bulk and powerful shields of an Executor-class command ship makes it all but unassailable. The armaments of each of these vessels are individually at least as powerful as equivalent weapons on Imperator-class ships, and many times as numerous. Nevertheless Executors rarely engage in space combat because few foes would dare a direct confrontation. Instead they serve as mobile command bases for the coordination of larger fleet actions and the supervision of ground forces.
The standard complement of starfighters is claimed to be two wings, totaling 144 fightercraft, although the size of the mothership's docking cavities indicate that it could easily accommodate dozens or perhaps hundreds of times more. During the years before the Battle of Hoth each wing typically included one squadron of TIE Interceptors and one of TIE Bombers. In later times more advanced starfighter models (eg. the elite TIE Avenger and TIE Defender fighters) would have become a greater component. TIE assault craft, shuttles, ground assault dropships and service / maintenance vehicles bring the total number of carried ships to over two hundred. For surface actions 25 AT-AT, 50 AT-ST walkers and similar numbers of other ground assault vehicles are reportedly carried. Three spare prefabricated garrison bases are kept aboard each Executor-class command ship for rapid assembly on planets which need lasting pacification measures.
In the years following the Battle of Endor the New Republic forces learned much about the weaknesses of these formidable warships. One of these potential weaknesses is the distribution of weaponry. Although the total number of guns is immense and the sleek dagger-like hull design gives most of these batteries a clear shot in almost any direction, the nett density of guns is much sparser than on a common mile-long destroyer [at least according to unverified published statistics]. Enemy starfighters very close to the hull are sometimes able to find shelter from most of the turbolaser batteries, especially in the midst of the canyonous structures which dominate the central regions of the ventral and dorsal surfaces. This weakness seems to have been inadvertently exploited against the Executor at the Battle of Endor, when rebel fighters were able to reach the bridge by flying close to the dorsal hull. Of course, surviving to reach the warship's hull is a major problem in the absence of the kind of cover provided by the general chaos and confusion prevailing at Endor.
Executor, the personal flagship of Lord Darth Vader as seen in The Empire Strikes Back. The Executor was the first ship in its class, a Kuat Drive Yards design constructed under tight security at the great shipyards of Fondor shortly after the Battle of Yavin. Here we see the underside of the mighty vessel. The huge “V”-shaped cavity presumably contains docking bays for shuttles, dropships and a multitude of carried TIE starfighters.
Thanks are due to, in alphabetical order of surname:
The KDY shipyards at Fondor, the birthplace of the Executor. A protocol droid belonging to a rebel infiltrator remarks at the size of the incomplete battlecruiser.
Stern view, during Executor's maiden voyage.
At the gathering of Lord Vader's fleet at the start of The Empire Strikes Back, a comparatively tiny destroyer moves into the shadow of the awesome Executor.
High-resolution scans of Topps' The Empire Strikes Back widevision card #13, depicting the gathering of Lord Vader's starfleet.
The Executor and attending destroyers approaching the planet Hoth.
The Executor coasts in space in the nearby Anoat system, neglecting the majority of the rebel ships which escaped Hoth in order to concentrate its hunt on the Millennium Falcon.
Captain Needa departs the Avenger in order to present a personal apology to Lord Vader. The looming Executor fills the background and another star destroyer casts a shadow on the flagship's upper hull. This shot is a very explicit indicator of the relative scale of the vessels.
The Executor pursues the Millennium Falcon near the planet Bespin. The companions of Luke Skywalker seek to escape his father's influence. Initially with its dorsal face towards the planet and the incoming freighter, Executor reorients itself to the primary plane defined by the two ships' trajectories.
Struggling to outrun the Executor while harried by TIE starfighters, the Millennium Falcon skims the surface of the great vessel along one of the major brim trenches.
The prow of the ship, on what is either the dorsal or ventral face (not conclusively determined according to current information). Orientation of earlier shots hints that this may be a ventral view, but this is not strictly necessary, given the freedom enjoyed by vessels in a zero-gravity three-dimensional space. The apparent absence of a two-hundred metre shelf on the lip of the brim trench at the prow (which should be seen on the dorsal side) also suggests that this is a ventral view. It makes sense for the Executor to manoeuver to keep its prey in a ventral arc, especially if the intention is to tractor it into a hangar.
Executor at a rendezvous with the Arc Hammer in LucasArts' Dark Forces.
The Terror passes over a destroyer in LucasArts' Rebel Assault II. This sequence shows the ventral faces of both ships.
The Terror benefits from a cloaking device.
Distant views as a star destroyer emerges from the shadow of the Terror.
Terror explodes catastrophically, exposing a cloaked Imperial Navy space facility in Rebel Assault II. The docked Imperator-class destroyers offer a good measure of the size of the facility and of the command ship.
An Executor-class command ship and attendant destroyers approach Coruscant, capital of the Galactic Empire, in LucasArts' TIE Fighter CD-ROM computer game. This ship is not the Executor herself, since Lord Vader is shown in simultaneous action elsewhere in the galaxy.
Rebel attack on the Vengeance according to one of the possible outcomes of Balance of Power.
Destruction of what appears to be an Executor-class ship in a possible outcome of the Rebellion computer game. However the cortex doesn't look as if it covers as much of the dorsal surface as on Executor.
Lord Vader arrives at Endor in Executor at the end of Shadows of the Empire. Some observers once hoped that this awesome and majestic scene would replace the original footage at the start of Return of the Jedi for the film's special edition. It was not to be.
Original storyboard from Return of the Jedi depicting Emperor Palpatine's arrival at Endor with the Executor. This sequence was omitted from the final film.
After the Emperor's arrival at the Endor Death Star construction site, the Executor assumed command and control over the surrounding space, including the authorisation of passage through the security deflector shield. Here we see a succession of beautiful views of the elegant flagship from the cockpit of a personnel shuttle crewed by devious saboteurs from the Rebel Alliance. In the later images, we are afforded a rare closeup view of the conning tower of the magnificent vessel. Images taken from this scene are very helpful for determining the size of the Executor in relation to the escorting destroyers.
Despite the absence of her master, Lord Darth Vader, the Executor led the Imperial naval forces at the Battle of Endor. In the background here we see a front view of the command ship with its retinue of star destroyers.
Close views of the brim trench of the Executor or possibly the communications ship at the Battle of Endor. The trenchis much higher than that of a star destroyer. Some of the trench guns fire red bolts.
At the climax of the Battle of Endor, Admiral Ackbar ordered a concentration of all rebel fire on the Executor, with all Alliance ships deliberately disregarding attacks from the other Imperial ships. The heavy barrage overtaxed Executor's power systems, causing shield failure. Distracted and exposed, the embattled flagship proved vulnerable to strafing runs by rebel starfighters. The small and maneuverable craft were able to find shelter near the the skyline and main hull of the giant vessel, with cataclysmic consequences. Seconds later the commander of Green Wing ended an ill-fated strafing run by colliding his crippled fighter into the bridge itself. The geometrical improbability of the impact suggests deliberate suicide piloting, or at least that he was already on trajectory towards the bridge before losing control. Executor then spun out of control and dove into the surface of the Death Star.
Executor dove into the Death Star with the main command bridge devastated and other control systems throughout the command tower incapacitated in a compound asynergy of damage. Admiral Ackbar watched on in relief. The loss of their great command vessel demoralised the remaining Imperial crews and ensured victory for the heavily outnumbered rebel fleet.
Visual representations of the Executor and its siblings vary greatly in the official literature. It is fitting that we take a look at a few painful examples and contrast them with the canonical form of the vessel, and some more careful fan-made attempts to recapture the essentials of this enigmatic design.
The Imperial Sourcebook:
It has been suggested that the erroneous WEG diagram be interpreted as if it were a completely distinct warship class, at the smaller length of 8km being a cruiser or battlecruiser. There are drawbacks to this proposal: (1) the shape of the tower neck is totally wrong for a KDY vessel; (2) the accompanying text in The Imperial Sourcebook indicates that Executor belongs to the described class. Of course, as Arhul Hextrophon acknowledged in the introduction to the Imperial Sourcebook, the entire document is biased to a rebel viewpoint and contains many errors of intelligence; therefore the two above-mentioned objections may not be insurmountable.
Essential Guide to Vehicles & Vessels
The Executor sketch from Essential Guide to Vehicles and Vessels shows a generically textured surface for the cortex. The choice of a dorsal view means that critical features are not visible, which minimises the scope of potential discrepencies. The forward edges of the cortex cavity are too pointed though. The schematic diagram and the text are more glaringly problematic.
Initial design sketches for Lord Vader's flagship; early designs for the Executor. Some of these sketches inspired distinct classes of Imperial warships seen in the Marvel comics and the TESB arcade game.
Maritime historian Anthony Tully drew produced these careful drawings of the Executor in November 1984, using all of the production art, comic art and model photographs available at the time. The illustrations hold up surprisingly well today's era of videodisks, widevision cards and video capture devices. The features are labelled in analogy to the pre-existing star destroyer blueprints of the time. (Images © copyright Anthony Tully 1984.)
Martyn Griffiths, sci-fi modeller, is undertaking a painstaking blueprinting project using all manner of photogrammetric and other techniques to determine the ship's proportions accurately. He kindly gave permission for some of his initial results to be displayed here (© copyright Martyn Griffiths 1999).
Ratio of Executor to destroyer length
The Imperial Sourcebook from West End Games mistakenly claims that a Executor is merely five times the length of a star destroyer. (Note that this figure first appears in the original edition of A Guide to the STAR WARS Universe, which was published many years before the West End material. Therefore West End are not entirely to blame for the error.) The STAR WARS Sourcebook, also from West End Games, claims that the destroyer is 1.6km long, which would make the Executor-class ships only 8.0km long.
In recent publications such as the Official Star Wars Web Site and STAR WARS Incredible Cross-Sections, there has been a cautious revision of the Executor length statistic. The new statements claim that the ship is over eight times the length of a star destroyer; meaning a length that is greater than, and not less than, about 12.8km. The Behind the Magic CD-ROM inconsistently uses both the 8km and 12.8km figures. It also contains an illustration falsely presenting the Executor as being only a bit more than seven times the size of a destroyer. This illustration does not match the sizes of the bridge towers, nor the orientation of the vessels, so that the command ship is foreshortened.
The illustrations on this page are clear evidence that an Executor is in fact more like eleven times the length of an Imperator-class star destroyer. In the first picture above, the grand vessel clearly dwarfs the three attending star destroyers. Pay special attention to the destroyer which is in front of the Executor's docking bay opening. If the stern of the Executor is extrapolated to its proper extent beyond the left edge of the picture then the projected lengths of the two vessels can be measured and compared. One can then correct for the orientation of the ships to gain limits on the relative lengths. The most important thing is that the destroyer is closer to the viewer and therefore relatively "magnified" by the effect of perspective. It can thus be shown that the Executor is about 12.5 times the length of a destroyer. Given that both vessels are at a similar distance from camera in this shot, the destroyer will not be greatly magnified by perspective, and this length ratio must be close to the true value. The only qualification is that the destroyer is pointing in a slightly different direction; this may reduce the lower limit by up to about ten percent.
Similar constraints result from geometric study of other pictures taken from the films. For instance one of the shots of Lord Vader's fleet in the Anoat system gives a crude upper limit of 25 times the destroyer's length. Precise study of other shots yields length ratios which are consistently in the vicinity of 11 or 12. One of the most valuable sequences for this purpose is the encounter between the Executor and the personnel shuttle piloted by rebel commandos. These images contain two destroyers moving in formation with the Executor. The first is slightly closer to camera than the command ship. The distance of the second destroyer is unproven, but is further away, possibly off the Executor's stern, portside. Length ratios obtained for the escort ships are 10.62±0.02 and 11.15±0.02 respectively. Combining these constraints, the command ship's length must be somewhere between 10.60 and 11.17 times the destroyer length. This is a definitive measure of the true size of the Executor and is consistently supported by every relevent shot in both The Empire Strikes Back and Return of the Jedi. The value of 5, expected from West End Games sources, is neverseen anywhere in the films.
The exquisitely-illustrated book based on an exhibition of the Lucasfilm Archives, From STAR WARS to Indiana Jones is in fairly good agreement with the calculated limits. Two pages are devoted to the Executor. On p.44 it says, in part:
... Executor, the flagship of Darth Vader, was conceived as eleven times the size of the original Star Destroyer of Star Wars. (For reference, the conning tower that rises from the Executor was supposed to be as big as the original Destroyer's conning tower.)
Size of star destroyers
There is weak evidence that ordinary Imperator-class star destroyers are in fact a few miles long rather than exactly one mile. This notion is mentioned in the context of a discussion of the destroyer design in Stephen Sansweet's STAR WARS: From Concept to Screen to Collectible. It seems possible that the Lucasfilm artists working on the original film designed the ship to be five or six miles long. If so then this original intention takes precedence over the one-mile figure given in secondary references. The size of the destroyer is dealt with on pp.42–43 of the Sansweet's book. A caption to the illustration on p.43 is explicit:
The final version of the Star Destroyer, built in several different sizes, was meant in filmic terms to be about six miles long.This implies that the Executor is at least 106km long.
On the other hand From STAR WARS to Indiana Jones, which gives the “eleven times” length figure for the Executor, supports the usual one-mile star destroyer theory.
These two conflicting references, which are both entirely based on the original Lucasfilm Archives sources, indicate an Executor length of 17.6km or 106km, depending on the true size of a star destroyer.
Independent calculations of the size of Lord Vader's star destroyer at the start of Return of the Jedi, based on the known width of the Lambda-class shuttle, gives a result of one mile to within the measurement uncertainties. (The result is 1.68±0.18 km.) Scale calculations based on the shots of the Millennium Falcon perched on the bridge tower of the star destroyer Avenger in The Empire Strikes Back also support the one-mile destroyer length.
The horizon method
It is theoretically possible to measure the length of the Executor by reference to the second Death Star. A careful examination of the curvature of the horizon of the Death Star in the scene where the Executor plunged to its doom should in principle produce the radius of the Death Star to the same scale. The absolute length of the ship could be determined assuming the true dimensions of the battle station.
In Return of the Jedi the diameter of the Endor moon is consistently 11.5±0.1 times that of the Death Star. This calculation can be accurately measured from the hologram in the rebel briefing, and from the whole-disk view of both bodies which was seen when the Rebel Alliance fleet emerged from hyperspace. To proceed from this point, it is necessary to know the absolute size of the moon.
The mass of the moon is loosely constrained by planetary physics. Too small a moon will not be able to hold a breathable atmosphere under the comfortable temperature conditions enjoyed by ewoks. The moon must therefore have a surface gravity which is a significant fraction of Earth's. At the same time, the Ewok hang-gliders would probably be unable to fly with exactly human-standard gravity (unless the atmospheric pressure at ground level is much greater than terrestrial conditions). Surface gravity of about 2/3 g seems reasonable; (it could only be stronger if the moon is endowed with a dense atmosphere; but the gravity cannot be much lower because of the atmosphere-loss constraint).
If the composition of the moon does not depart drastically from that of terrestrial planets in our solar system then the best solution for its size gives density of about 4.5 g/cm³ and a radius of about 5200±300km. This gives an approximate Death Star radius of about 450±26km. For further information read Death Stars.
It ought to be possible to fix the Executor's size by using this radius to scale the crash scene.
Unfortunately this elaborate method collapses in practice. The Death Star II's horizon curvature is so slight that tiny uncertainties in measurement lead to large uncertainties in results. Put bluntly, this technique is too imprecise. My own initial efforts with this technique produced values for the ratio of Executor length to Death Star radius varying from 0.038 up to about 0.18. The lowest horizon result for the Executor's size yields a length of 17±2km, which is in agreement with the length calculations based on a one-mile star destroyer length. Of course, the problem is that it is also too easy to obtain a very different kind of answer.
Even if it were not for this unreliability, the measurement is under fundamental doubt. The section of the battle station's surface seen near the point of collision was in fact produced from miniature model tiles laid on a flat horizontal surface. It is quite possible that the apparent curvature of the horizon is wholly illusory.
Bridge tower comparisons
The absolute scale of the Executor can be determined by a careful examination of the bridge tower section, especially as it appears in Return of the Jedi. Several closeups of the front face of the command tower are seen in that film.
One key is that the distinctive triangular windows of the bridge are visible on the model which was used for these shots. The bridge structure is a slightly rounded bulge positioned symmetrically at a point which is about two-thirds of the height of the face of the command module. The absolute width of the bridge is approximately known from interior scenes. The absolute length of the bridge should be of the order of 15 - 20m. This can be used in conjunction with an image of the tower model and a measurement of the tower:ship size ratio to yield an absolute ship length.
Neglecting distortions of perspective and rotation in the primary photograph of the tower module, the bridge is one sixth of the width of one of the sensor globes. Correcting the orientation and perspective of the view shows that the bridge width is closer to a quarter of the globe diameter.
With this established, we must next determine the ratio of the globe diameter to the ship length. In most images this is imprecise because the globes are so tiny in comparison to the whole vessel. However in large broadside photographs can give fair results. Two independent broadside images give a ratio of ship length to globe diameter of 391.5 and 439.0 respectively. Because the ship length will appear shorter if the vessel is not perfectly perpendicular to the camera's line of sight, these two figures are lower limits.
Using crude corrections for the projection-shortening of the bridge on the tower face, the Executor's length generally turns out to be of the order of twenty or thirty kilometres. To obtain a length approaching five miles, the orientation of the conning-tower photograph would have to be over seventy degrees, which is disproven by even a casual inspection of the actual image. Even reducing the figure for the ship's length as low as 17.6km (11 miles) requires an angle of over fifty degrees, which stretches the bounds of credulity if we judge the image by eye.
A more precise value of the Executor's length can be obtained by determining the diameter of the sensor globe without reference to the bridge. Under the assumption that an Imperator is 1600m long, measuring pictures of the Devastator model determines the globe diameter as 41m with an uncertainty of about two percent. Depending on the perfection of the orientation of the Executor in the broadside images, this globe diameter yields minimum values for the total ship length of 16.2km and 18.1km. This is in good accord with the geometrical studies of star destroyers overlapping the Executor in the movies.
Thus an examination of the tower and bridge windows and scanner globes of the Executor yields an absolute length which is greater than or consistent with the 11-mile value indicated by other lines of evidence. For further information refer to Bridge Towers.
David West Reynolds has kindly taken some measurements of the actual Executor model. The total length of the model is 277.0cm and the command tower is 4.2cm wide. If we know the absolute width of the tower, we can then determine the absolute length of the ship.
The Imperator-class star destroyer has the same basic tower as the Executor. (The structure is probably a constant brand feature of all major warship designs from Kuat Drive Yards.) By examining the destroyer proportions, and assuming its well-established length (about one mile), we can determine the absolute tower width. Photographs in STAR WARS Chronicles and STAR WARS to Indiana Jones yield upper limits of 284m and 282m, an estimate of 267m and a lower limit of 245m. There may be some slight variance between the different models.
The true width of the tower is probably in the range of 265 - 270m. Therefore the Executor's length, based on the tower yardstick, is:
Warship model kits are built to certain discrete conventional scales. Special effects artists like the modellers of Industrial Light & Magic adhere to these standards in order to help maintain consistency in the on-screen dimensions of their creations, because they incorporate parts from commercial warship models, and in deference to tradition. One of the most common natural scales for battleship models is 1/620, which appears to have been used for the Avenger model of the common Imperator-class star destroyer.
In books, the length of the Executor model is usually stated as 2.82m, which obviously puts it at a different scale. For such a stupendous vessel none of the ordinary scaling standards is applicable. However [according to Martyn Griffiths] the natural extension to the set of standard scales is 1/6200. If this is correct then the precise length of the real Executor is 17.5km, which at 10.9 miles is neatly at the low end of the range of possible dimensions indicated by other lines of reasoning.
David West Reynolds has directly measured the model at 2.77m, which is somewhat shorter than the published version. Therefore if the intended scaling of the ship was 1/6200, the intended length of was closer to 17.2km.
STAR WARS Exhibition
Several years ago many of the important props from the Lucasfilm Archives were put on public exhibition in San Francisco. According to Martyn Griffiths and Frank Bitterhof, many of the models were associated with in-house technical specification cards produced by ILM. The card relating to the Executor made an unambiguous statement that the vessel was eighteen kilometres long. The present fates of this card and others in its series are unknown to the general public.
In 1980 George Lucas led a televised visit to the ILM special effects workshops. Among the important models that he demonstrated were the full-length model of the Executor and the larger scale model of the brim trench region from near the prow. Interestingly, there was a small star destroyer model sitting atop the Executor model off to one side. The size relationship between these two models matches that of the star destroyers seen moving over Executor's wing during the approach to Hoth and Captain Needa's shuttle scene. It seems very likely that this star destroyer model was made to exactly the same scale as the Executor for the purpose of making these shots. The relative sizes of these models are difficult to calculate from the television imagery, but they seem visibly consistent with the eleven-mile length reached via other methods.
Conclusion for absolute size
If the star destroyer length is accepted as 1.6km then the Executor's length is given by the length ratios between the two ships. Observations from scenes in The Empire Strikes Back and Return of the Jedi where one ship occludes another constrain the length ratio to be within the range of 11.0 to 12.0, corresponding to an absolute range of 17.6km to 19.2km. Measurements based on the collision between Executor and Death Star II are inconclusive, because the curvature of the battle station's horizon cannot be measured with sufficient precision. A chain of geometric reasoning involving two independent Executor broadside views and the size of the sensor globes indicates lower limits of 16.2km and 18.1km. The conventions of the construction of warship models indicate a length of close to 17.2km. Direct measurements of the Executor model using the standard KDY command tower as a yardstick indicate a length of 17.6±0.2km, which is consistent with the photogrammetric methods and other approaches. I conclude that Executor-class command ships are somewhere between 17.4km and 17.9km long; and certainly much more than the mere 8km claimed by some Roleplaying Game sources.
It is to be hoped that the tragic underestimate of this warship's size which was accidentally promulgated in certain references will not be further compounded in future STAR WARS novels and reference books.
Examination of various photographs yields limits on the other dimensions of the Executor design. The ratio of the vessel's wingspan to the width of the command tower is determined by images from the front and behind. Absolute lower and upper limits on this measurement are 21.6±0.6 and 23.9±0.8 respectively. The command tower itself is approximately 270m wide. According to the scale of the model and the thickness of its raw materials, the armour of the main planar hull sections is not more than 19.7m thick.
If enough of the ship's side lengths and positions of the vertices were known, it might become possible to calculate the total volume approximately. That determination is not feasible at this time. Once the volume is known, the mass might be estimated, if we make some intelligent guesses about the average density of the ship's material. It is probably denser than air, simply because much of the ship contains air, and the Lusankya was not naturally buoyant in Coruscant's atmosphere. The average density is probably less than the density of an unadulterated heavy metal, because the ship's internal structure is a honeycomb of corridors, rooms, machinery and other air-filled or evacuated chambers. However the fuels of a warship have characteristics unknown to us at this time; if they are in exotic forms as energy-dense and mass-dense as those of the Death Stars then the total mass of fuels could exceed the dry weight of the ship.
History of the “five mile” fallacy
A brief summary of the emergence and present status of the erroneous Executor-class length in the STAR WARS literature is given on a dedicated page. The basic data used for this summary was kindly provided by Anthony Tully.
The canonical evidence proves that the Executor is about eleven miles long, beyond any doubt. References that assign Executor to a class of five-mile or eight-mile ships are erroneous.
Several questions must be faced now. (1)Do there exist any classes of KDY-designed warships that are exactly five or eight miles long? (2) If so, then do such classes include any of the ships mentioned in the official literature that were previously assumed to be members of the Executor-class? (3) Should any of these classes be called “Super-class”?
Firstly, it would be alarming if there was a desert of warship designs between the implicitly mid-sized, one-mile star destroyers and the mammoth commandship Executor, which is eleven times as long and perhaps a few hundred times as massive. Fortunately the visually rich comic literature shows many glimpses of KDY dagger-style warships of various classes and intermediate sizes. In addition to some small and medium vessels, the official literature depicts several kinds of warships which, judging by the scaling of yardsticks like the standard bridge tower, are several miles long. None of them seem to be exactly five or eight miles long, but it is reasonable to suppose that other ships exist in that range but haven't yet been seen in movies or comics.
Some novels describe five-mile “super star destroyers” which are supposed to be younger siblings of Executor. In some cases the authors have probably been over-dependent on flawed spin-off references, and they may be genuinely innocent. In other cases the incessant and redundant recitation of the incorrect length may reflect a peculiarly intransigent attitude which asserts the spin-off references above the canon, in defiance of the rules of precedence stated in the first issue of STAR WARS Insider, and restated in the introductory remarks of the STAR WARS Encyclopedia. Some of these books might be rescued and retro-rationalised if it is possible to say that the named vessels are not in the Executor-class but instead represent smaller designs. The evidence requires detailed inspection.
|Lusankya||Mistaken for Executor by its builders; the difference was only discovered some time after the rebel conquest of Coruscant. Drawings in Crimson Empire have hull dimensions and gross cortex features identical to Executor. Therefore Lusankya must be 11 miles long, and belongs to the Executor-class.|
|Must be the same as each other, in order for Zsinj's misidentification ploy to succeed.|
|Guardian||Must be 11 miles long, because the published illustration is visually indistinguishable from Executor-class. Visual length scaling based on nearby star destroyers is consistent with a length of 11 miles, and inconsistent with a length of 5 miles.|
|Terror||Features and proportions are sufficiently similar to Executor for this ship to be placed in the same class.|
|Intimidator||Described as 8km long but also described as “Executor-class.” The latter probably deserves precedence; it should be a 11+ mile vessel.|
In the movies, the Executor is only called a “star destroyer” or “super star destroyer” by loose-talking or stressed characters — never by naval experts in analytic circumstances. Princess Leia, a politician and not a naval expert, exhaustedly muttered “star destroyer” as she escaped from Bespin. Likewise, Lord Vader was upset when he called for a ship and left Cloud City. It isn't clear whether he meant to signal Executor directly or via a true star destroyer attending his flagship (somewhere off-camera). Admiral Ackbar, evidently floundering with human language, called the ship a “super star destroyer” in the heat of battle. However, calmer characters call the Executor a “command ship,” [Solo approaching Endor; Palpatine giving orders to Vader]. C-3PO [in Classic STAR WARS] says that it looks like an oversized “battlecruiser” — which implies battleship scale.
Executor's mass and power are orders of magnitude beyond a mere destroyer. It is the premiere warship of its time: a dreadnought — the top of the range of battleships. Therefore the term “super star destroyer” can only be slang. It is a widespread colloquialism, of rebel origin, covering warships exceeding destroyer scale: star cruisers, star battlecruisers and star battleships, including star dreadnoughts. [ITW:SWT]
Thus the term “Super-class” appears to be a corruption of slang. A “Super-class” of warships could only formally exist if the lead vessel had been named Super. In principle there could exist a class of five- or eight-mile warships with a first member called Super, but this class would not include the Executor (which is the lead ship of its own class). In any case, it would still be inaccurate to label such large ships as “destroyers.”
The colloquial term “super star destroyer” should be avoided. This is not mere pedantry; the term is actually misleading. In addition to its harmful contribution to the confusion over Executor's length, the term is overly broad. The description “super star destroyer” has been applied to vessels of widely varying classes and roles: e.g. Allegiance and Eclipse in Dark Empire. The only shared property of these warships is that they are slightly or greatly bigger than the most common, one-mile destroyers.
This elegant image of the damaged Guardian, from Wanted by Cracken is important as an example of an image in a roleplaying game reference which has been allowed to depict the command ship and star destroyers in realistic proportions.
Box art from the Balance of Power computer game. Remarkably, this image portrays an Executor-class command ship in valid scale and very fine detail. Unfortunately the ship shown in the game itself has the usual incorrect dimensions.
The original roleplaying game illustration appearing in The Imperial Sourcebook. Note the exaggeration of the bridge tower's relative size.
Starship size comparison chart given in Dark Empire Sourcebook. Unfortunately the proportions and length of the Executor-class ship are seriously and demonstrably wrong, as discussed elsewhere in this page. The true length of Executor is slightly longer than the length assigned to the Eclipse-class and Sovereign-class ships shown in this diagram.
A broadside side-view of the Executor, in low and high resolution. Observe that the bridge tower is proportionately much smaller than in the illustration from The Imperial Sourcebook, above.
Another full side-view of the Executor. This image is taken from slightly above the midplane of the vessel, affording a better view of the dorsal superstructure.
George Lucas demonstrating the Executor model on a Cronkite television special. A small star destroyer model is seen sitting on the flagship's starboard wing in the first image.
The main bridge of the Executor-class design is located in a command tower that matches the basic design of towers of other significant warships built by the Kuat Drive Yards corporation. The towers probably are a trademark brand feature of this particular shipbuilder. For observers of the Imperial Starfleet, the tower structure serves as an important yardstick for the analysis of the Executor and its relatives, and the fine details including the bridge layout may serve as fingerprints of individual vessels or indicators of the date and site of construction.
The main bridge of the Executor protrudes as an ovoid blister in the centre of the forward face of the command tower. Triangular panoramic windows span the edge of this blister, offering command officers a convenient view of space ahead. Details of bridge interiors are outlined in the separate Bridge Towers document.
One point of special interest in the bridge of the Executor is that an extensive refit appears to have taken place between the battles of Hoth and Endor. Originally, the control consoles in crew pits were aligned parallel to the longitudinal command walkway that leads between the exit and the observation windows. At the time of the ship's destruction, the consoles were instead aligned in rows transverse to the walkway. The number of windows also appears to have changed, and the alcove virtual viewports were inactive at least during the first part of the Battle of Endor. An extra console was mounted near the bridge exit, for the sake of traffic control near the Endor construction zone.
It could be argued that these changes signify that the vessel at Endor was not the Executor, but was a sister ship with a different name. However this seems unlikely considering the continuing association of Admiral Piett and Lord Vader (whose customised living quarters must be more expensive to move than any refit of bridge consoles or windows). The Imperial Navy probably has thousands or millions of admirals who are equal or superior to Piett in rank and ability; it would require a remarkable stroke of luck for him to be reassigned to exactly the command ship that served at Endor, if it were not the Executor.
The Lusankya had an auxiliary bridge elsewhere in the ship, and since she was built at the same time as Executor, Lord Vader's vessel probably had a backup bridge as well. (Obviously the officers and crew of Executor were unable to reroute propulsion control to this bridge before Executor descended into the hull of the second Death Star.) Intimidator, a ship of later construction, had at least one additional nodule on its bridge tower (for a separate observation deck) and a gunnery bridge located at another place that has not yet been determined. At the Battle of Endor the Executor was accompanied by a communications ship which belonged to a somewhat smaller warship class, but sprouted a much greater number of bridge nodules.
A closeup view of the Executor command tower model used for the cataclysmic collision of a rebel A-Wing into the bridge itself. The bridge is a slightly bulbous structure with a row of triangular windows near the right edge of the image, about two-thirds of the height up the front face of the command module. [CINEFEX]
Another view of the Executor bridge tower, showing the explosion of a sensor dome after a heavy assault by rebel A-Wing fighters. In this image the bridge windows shine brightly in the middle of the front face of the tower.
A Petty Officer stands in front of the deactivated alcove virtual windows prior to engagement of rebel forces at the Battle of Endor.
The shuttle Tydirium approaches the Executor.
The stolen shuttle Tydirium flies past the front face of the command tower of the Executor several levels below the deckplane of the main bridge.
Executor bridge interior, facing out the panoramic windows.
As with most dedicated warship designs, the sleek and distinctive dagger-like form of an Executor-class ship's hull provides maximum line of sight coverage for most of the guns. Flat hull surfaces minimise obstructions in as many directions as possible, and the forward-pointing form is well suited to a ship designed for dominance or parity in a chase or stationary broadside battle. This hull form suits a ship that is designed for an assertive, aggressive role. [Also refer to discussion of weapon ranges.]
There is only incomplete evidence regarding the real precise distribution of weapons. Analogy with smaller warship classes suggests that a majority of the big guns (presumably turrets like those on Imperator star destroyers) may be mounted on the broad flat dorsal and ventral surfaces: with the best possible firing clearance above the hull and ample space for massive power feeding systems below the hull. It is also likely that larger number of smaller guns are mounted in the brim trenches, rough cortex areas and at semi-random sites on the major hull planes.
The Executor's weapons are not clearly visible in any casual, overall view of the ship; they are much less conspicuous than those on a star destroyer. In relative terms, each of the largest guns is a small part of the ship. In absolute terms the big guns may be of the same scale as a star destroyer's heaviest turrets: tens of metres long. Perhaps this is a natural upper limit for the size of a turbolaser turret, with optimal range, tracking and power feed from the ship's reactor systems? A bigger gun might fire shots of higher yield, but its massive barrel would be more unwieldy to aim. If so then the solution for the Executor's armament is not to install ultra-heavy guns but to distribute the firepower through a large constellation of conventional heavy batteries. The total number of supportable guns ought to be proportional to the main reactor output.
Can the largest weapons be visually identified at all?
Several hundred of the largest visible lumps scattered across the dorsal hull are about the same area as the heavy gun turrets of star destroyers (eg. the eight eight-gun turrets of the Avenger). They could be a similar kind of turret. The reveallingly illuminated scene of Executor's plunge into the surface of the second Death Star shows at least 126 blisters on part of the starboard side. This extrapolates to on the order of 400 bumps on the dorsal hull. Individually counting the blisters in close-up views of the hull reveals about 616 on the dorsal hull and a further 326 on ventral surfaces. This total is about 118 times greater than the 8 heavy turrets on one of the Executor's escorting star destroyers.
Other classes of large guns may be found throughout the dorsal cortex and similar ventral surfaces, although they may be difficult to distinguish from harmless but pointy antennae and aparatus. The cortex contains several rod structures of several tens of metres' length. Some are single and others are in small rows of up to three. Many point vertically (up from the midplane of the ship). If they are movable guns, and not antennae, then they are able to elevate up to 90° and a rest in that position. Are they antenna masts or are they uniquely large gun-barrels? This is uncertain, but it is remarkable that most sensor and communications devices [on STAR WARS starships] are dishes or geodesic “radome” shapes.
The heaviest and most powerful guns are used against the potent shields and thick hulls of large enemy warships. However an Executor also mounts a greater number of lighter guns with low firepower but the ability to turn and aim rapidly to target starfighters and other small or nimble targets. These weapons include the point-defence guns that tried to shoot down rebel fighters flying over cortex surfaces during the Battle of Endor. The A-wing that eventually crashed into the Executor's bridge had been clipped by this kind of fire. The numbers of these point defence guns may be impossible to count using presently available evidence, but they are likely to be many times more abundant and draw much less than the total firepower of the heavy turrets.
Apocryphal sources [mostly roleplaying games and the books that follow them] credit an Executor-class vessel with over a thousand turbolasers, ion cannons and other weapons. These armament statistics were based on drastic underestimates of the Executor's length, and thus the true number of guns would have to be many times greater (even if we didn't have independent counts of hull features, above).
Even if we allow for the scaling errors, the roleplaying books give Executor a gun density much lower than that of a star destroyer: about seventy times the area but only a few times as many weapons. We could make lame excuses for this — Executor designed as a noncombatant staff vessel, always assumed to be under the protection of better armed destroyer escorts — but it is more reasonable and efficient to assume that the game statistics are irretrievably ill-conceived.
We are better served by closely inspecting of the ILM special-effects model, and/or tracing the locations of blasts fired in the movies.
The locations and densities of a few types of weapons can be estimated from a few reliable observations of beams discharging from the (presumed) gun emplacements.
At one point during the Battle of Endor the Executor was engaged in a broadside exchange with a rebel frigate at point-blank range immediately over the main portside brim trench. From this we can conclude that the brim contains at least one class of moderate or heavy anti-ship batteries. In the three-hundred-metre section of brim seen firing on the rebel frigate, there were at least three guns. If the density of brim weapons is constant over the whole perimeter, there must be at least several hundred of this type of weapon alone.
In the moments before the Executor's downfall, rebel starfighters flying across and throught the dorsal cortex came under sporadic anti-starfighter fire. The terrain gave the fighters excellent cover, but there were at least a few guns firing within a stretch of just a few hundred metres. If we knew the total area of the cortex then we might estimate the number of point-defence laser cannons from a density of one per square with 100m or 200m sides.
The Executor also had the ability to project tractor beams, as seen when she persued the Millennium Falcon from Bespin [TESB]. At first the Falcon was either out of range or the tractor beam was not ready. Were Admiral Piett's crewmen slow, or is a tractor beam always this unwieldy to use during a hot pursuit? Does it take more than a minute to activate?
Later, the freighter dove right into the starboard brim trench, and gained cover from the tractor beam and most of the ship's guns. Then, as the Falcon came into open space beyond Executor's bow, the hyperdrive was repaired and the rebels jumped to safety. Unfortunately for Lord Vader, we do not have any filmed documentation of the effectiveness of Executor's tractor beams when they are brought to bear.
Executor exchanges fire with a relatively tiny rebel frigate. Most of the Executor's fire against the frigate comes from guns in the section of brim trench adjacent to the rebel ship. Amusingly, the frigate looks as if it would almost fit within the larger ship's brim. Also, judging by the separation of the ships, the visible component of the turbolaser bolts appears to be move at mere kilometres per second. This is different from the speeds of bolts seen in other incidents and is obviously much slower than the invisible destructive part of the beam.
Rebel starfighters take cover in the canyonous features of the Executor's dorsal cityscape terrain, but anti-fighter fire still rains heavily here.
Struggling to outrun the Executor while harried by TIE starfighters, the Millennium Falcon skims the surface of the great vessel along one of the major brim trenches.
As Executor dives into the second Death Star, we see a good top view that permits a partial count of the raised bumps that are probably big gun platforms. In the first image here there are at least 106 visible bumps, and at least 20 more are shown in the second image.
The Executor's shielding defences were one of its most formidable features [according to the Williamson Classic STAR WARS comic strips]. The ship was considered virtually unassailable in the years between the battles of Yavin and Hoth. During the Battle of Endor, Admiral Ackbar realised that the mighty flagship could be defeated if his Calamarian cruisers subjected the shields to an especially concerted barrage, resulting in shield failure and exposure of sensitive structures (eg. bridge and scanner globes) to pinpoint starfighter strafing.
In the present literature there are few quantitative indications of the Executor's precise shield strength. We know that a deliberate and concentrated bombardment by somewhere between half a dozen and two dozen Mon Calamari cruisers caused shield failure within a matter of minutes. Unfortunately we can't quantify the shield capacity directly because we don't yet know the maximum output of Mon Calamari warships' guns. To total yield of Ackbar's barrage was probably the equivalent of a continual bombardment by a comparable number of Imperial star destroyers over the same time period.
This upper limit on the shield capacity is complemented by a lower limit provided by the Classic STAR WARS comics, which chronicle an accident in which Admiral Griff's three destroyers or light cruisers (of at least one mile length) collided with the particle shields at presumably relativistic speeds (during reentry from hyperspace). The three impactors were annihilated, and Executor was unscathed but suffered serious temporary shield loss, requiring it to delay its mission.
The image of this incident carries interesting hints about the dynamics of particle shields. The fireballs from the collided ships were flattened along a smooth surface that stands several hundred metres above Executor's dorsal cortex. This presumably is the depth into the field at which the velocities of the fastest debris particles were damped to zero velocity relative to Executor. It may be representative of an equipotential surface corresponding to the kinetic energy or momentum density of the impactors.
Three star destroyers emerge from hyperspace directly into a collision with the Executor. The huge warship's shields absorb the energy of the relativistic impact, at a range of up to a kilometre, and the destroyers are instantly pulverised.
Executor-class command ships carry vast numbers of starfighters, shuttles and other support ships. The commonly reported numbers are much smaller than the capacity that would be expected for a ship of this size, (at least according to Roleplaying Game data), but they still require significant docking facilities. In presently known external views of Executor-class ships, the distances are so great that the individual hangars are either invisibly small or obscured on the hull of the vessel. The exact hangar locations are a minor mystery.
The immense “V”-shaped ventral cavity seems to be one huge deployment bay for the accommodation of large starships. The role of this feature may be analogous to a large drydock, akin to the proportionately smaller docking bays of a star destroyer. At a length of about 4.7km, this bay is spacious enough to envelop a star destroyer almost as well as a destroyer can enclose a corvette. (The only problem being that the Executor-class cavity is somewhat too shallow for complete enclosure.)
The cavity constitutes a large portion of the ventral surface of the forward regions of the ship. Its total size must have been dictated by the vessel's intended mothership role and other such functions; the form and position of the cavity are subject to intrinsic engineering constraints. Its aggressively non-rectangular shape is probably due to both aesthetics and the designers' need to prevent the edges from approaching the brim trench. Such a cut across the ventral hull plating would weaken the overall superstructure.
The rear end of the mouth-like space splits into two branches, symmetric about the keel-line, which defines what might be colloquially called the “tongue” of the ship. It is possible that the bay avoids this area so that it does not expose a major component of the power or propulsion systems buried nearby. Between the tip of this feature and the forward point of the bay there runs a flattened spine-like ridge along the cavity roof, several hundred metres wide. The spine's thickness is a significant fraction of the bay's depth, and it may cover another vital internal system which has longitudinal form and/or it may be structural reinforcement compensating for the coincidence of the ventral cavity and the weak dorsal cortex. Other areas of the ceiling are tiled in relatively smooth terrain exhibiting roughly rectangular lumps and indentations on the order of a hundred metres across. The vertical walls of the cavity consist of crenulated surfaces with abundant portal lights, similar to the irregular surfaces of the brim trenches or the dorsal city-like terrain.
In Galaxy Guide 5: Return of the Jedi there is a description of an incident involving the Executor's docking facilities and the Millennium Falcon. At one point in the Battle of Endor, Calrissian found himself too close to the underside of the Imperial command ship. He briefly took cover in the main ventral cavity, flew into a hangar of some kind and through internal staging areas. The freighter made a hasty exit after firing on its surroundings to create a diversionary fireball. Unfortunately this account does not specify the exact location of Calrissian's hangar apertures.
Not all of the hangars are found in the main cavity area. On the centre-line of the ventral surface of the ship's fantail there is another lesser cavity which is several times the depth and expanse of the primary docking bay of a star destroyer. The Knight Hammer in Darksaber had at least one small hangar for TIE bombers in this aft bay. The bay is dissected by a peninsula of ordinary hull laid in the direction parallel to the ship's axis. In some photographs, this feature seems to have a substantially open dorsal surface, which is out of sight and may possibly be a sheltered site for some of the hangar and docking facilities. One of the larger hangars in Crimson Empire is here.
In the special edition of The Empire Strikes Back, Lord Vader's shuttle is seen to approach the main bay, and is then seen inside a standard Imperial hangar (about sixty metres wide) similar to those of the Death Star II, but somewhat wider than the known hangar apertures of an Imperator-class star destroyer. It seems too large for its external appearance to match any of the bright lights distantly observed on the inner surfaces of the main deployment bay.
Surrounding walls and other hangars are visible in the background beyond the hangar mouth. This region looks vaguely similar to the primary bay of a mile-long star destroyer, and it has similar scaling cues. If we assume that one of the hangars on the opposite wall is equivalent to the point-of-view hangar, the implied width of the whole bay is either four hundred metres or over six hundred metres. Thus, the Executor's bay may be as much as four times wider than a star destroyer's primary bay.
Unfortunately the bay's size and shape are difficult to reconcile with any exterior views of the vessel. It must be a sub-cavity within one of the known external features, but its location is very uncertain. It is too large to be rationalised as an insignificant dent in the primary hull, and the featureless walls are a poor match for the crenulated city-like terrain dominating the inner surfaces of the great exterior cavities.
There may exist possible locations among the features of the roof of the main cavity; perhaps in one of the corners which is infrequently seen. Otherwise it could be set in a corner of the keel-line spine bisecting each bay, or else at the point of the “V” of the larger cavity. Unfortunately the inconsistent wall texture is a problem for these theories.
Another possible site for docking and hangar facilities is the forward-facing wall of the “tongue”-like feature of the main cavity. There are dark indentations on this surface which seem vaguely rectangular in available images, and they may be on the order of a hundred metres long. This still might not be big enough though, and the bay may need to fit into the slot with an unorthodox orientation. Furthermore, closer inspection of the original model might well prove the rectangular features to be a mirage.
The bilateral symmetry of the Vader's bay aperture is clear, and the angles and proportions of the far wall's edges are suggestive of the two flat surfaces of the ventral hull plates. This may suggest a location somewhere on the keel line. Unfortunately there is no place on the hull of the Executor model where a bay of this size could be located inconspicuously.
The presence, distribution and size of smaller docking bays or hangars on the forward wall of the main cavity is unknown, because to date no adequate photographs of this region of the ship are available. In tactical terms a place on the forward wall of a cavity is the best, least exposed and least vulnerable position for hangars on a combat starship, therefore it would be unsurprising to find cavities there. There is a chance that Vader's hangar could fit somewhere inside this mysterious area.
View of the main docking cavity, centred on the “tongue” region. The start of the spine ridge on the bay's roof can be seen. A common star destroyer, sitting in the foreground, would easily fit into a corner of the bay.
Lord Vader's shuttle lands in a hangar of the Executor after his excursion to Cloud City on Bespin. Some details of the nearby docking bay space are visible in the distance beyond the hangar entrance. The docking bay details are enigmatic; difficult to reconcile with features of both docking bays known in external views of the warship. The one thing which seems certain is that the docking bay is on a dorsal face of the ship. [CINEFEX; movie frames]
Lord Vader descends the ramp of his shuttle and approaches a small reception in the docking bay. [TESB movie frames]
A yellowed image of the aftmost region of the tail docking bay double cavity. [STAR WARS Chronicles]
Aft ventral views of this under construction but nearly complete Executor-class ship show the fantail docking bay very clearly and establish its position in the vessel. [STAR WARS Chronicles]
A shuttle arrives at the Terror in the computer game Rebel Assault II. Unfortunately the sequence contains few clues to the location of the hangar on the overall superstructure.
Details of a ventral hangar area on the Lusankya, after its repair and refit by the New Republic [Crimson Empire comic]. The aperture is much smaller than the exposed docking bay of an Imperator-class star destroyer, and it is not situated within either the forward or the aft ventral cavities. It seems to be on the keel-line just a few hundred metres forward of the start of the fantail. This is not the same docking area as was seen in The Empire Strikes Back: Special Edition, nor Rebel Assault II. It may be a non-standard modification made after the Battle of Thyferra, following extensive damage inflicted on the main cavity, but this part of the Executor-class design has not been imaged in well enough to be sure. Although the aperture is small and conservative, the internal hangar area is vast. NOTE: the movies contain sufficient clear views to prove that Executor does not have an aperture anywhere near this region.
A rebel transport docks with the Lusankya. This docking bay complex is a few hundred metres across, more suitable for receiving medium-sized vessels. It looks like the fantail docking cavity. [Crimson Empire comic]
An important Imperial officer arrives at a fleet in Rebellion. The location of the hangar is uncertain, but it is important to note that no other part of the ship is visible beyond the hangar mouth. [Rebellion computer game]
Vessels of the Executor's class possess the three major forms of propulsion which are standard to starships in the Palpatine Era. Hyperdrives are mysterious devices which convert the ship between realspace and the superluminal aspect of reality known as hyperspace. Repulsorlift engines are concealed within the ship, provide an antigravitational thrust, and are the most effective form of propulsion within a significant local gravity well, such as in the vicinity of a planet or other large natural body. (Within six diameters of a habitable planet, according to the novel of A New Hope.) Sublight thrusters hurl directed streams of subatomic particles from the back of the ship at enormous sublight velocities, thus imparting an impulsive acceleration to the whole ship and allowing for movement in deep space below lightspeed.
Executor-class ships have thirteen sublight truster cylinders of diameters varying in the range of several hundred metres. The thrusters are all backward-facing, and located in three separate banks which are transverse to the primary axis of the ship. They are substantially exposed on the ventral face of the vessel, and surrounded by features which hint at internal propulsive systems and reactors which must be at least on the order of a few kilometres in size. The first and second banks are divided into port and starboard clusters. The total number of thruster nozzles in the first bank is six; and for the second bank four. The third bank consists of a single cluster of three engines located in the middle of the underside of the fantail, just forward of the large docking bay cavity of the tail.
The nozzles appear in three different diameters. On the original special-effects model, they are 4.5cm, 3.5cm and 3.3cm in diameter at the lip. In absolute terms, these diameters are approximately 290m, 223m and 210m. The three nozzles of the aft bank, the outboard nozzles of the middle bank and the central nozzle of each wing bank are all 290m. The outboard engines of the middle bank are 223m; and the flanking engines of the forward bank are 210m.
Some references state that these ships have only nine thrusters. They are in error. The misunderstanding arises from an excessively trusting interpretation of a distorted drawing featured in the first edition of The Imperial Sourcebook. This picture does not allow for all three of the thruster banks. Thankfully, today there is abundant photographic evidence for the true engine structure of the Executor and its younger sisters. The Executor toy model produced by Galoob is sculpted with commendable accuracy in this respect.
The placement of the engines of the forward wing banks is a matter of some mystery and dispute. In the absence of precise schematics, it is difficult to devise a configuration that matches the outline of the ship as seen from all angles. It seems most likely that the apertures of the outboard engines are higher than the inner engines, although all the engine axes point in the same aftwards direction. The vertical displacements of the successive engines in each bank follow the slope of the ventral hull. The structural blocks sitting between the engines seem not to share this slant however; they all appear to descend to the same vertical depth below the plane of the brim trench.
Return of the Jedi provides some evidence indicating lower limits on the accelerative capabilities of the Executor. Along with its attending destroyers, the Executor moved into place to trap Ackbar's fleet, with a linear deceleration on the order of a thousands of G, as seen on the tactical monitor of the Endor bunker control room. The transverse acceleration and turning capabilities of the ship were demonstrated when it plunged into the second Death Star. If the fall of the Executor was due to the station's artificial gravity then we know that the ship was previously capable of resisting the drag by applying a continuous counter-acceleration. If it was an engine misfire then we know that controlled accelerations of the same magnitude are also possible. Either way, the Executor can turn within a range not much greater than its length, within a few seconds, and can accelerate and decelerate along its heading by thousands of G.
The shape of these ships is obviously unsuitable for landing on the solid surface of a planet, but the force of gravity on a habitable world is much less than what the Executor experienced at the start of the Battle of Endor. The ship's tolerance to vertical or transverse forces might not be as great as a few thousand G, but Lord Vader did at least once order her to dock at a ravine base [on Krake's Planet, Marvel SW #63]. Special preparation and support was ordered from the base; the facility may have included arrays of repulsors and mooring towers suitable for an eleven-mile vessel. Years later, the Lusankya, supposedly a twin of Executor, was able to lift off its concealed place on the surface of Coruscant, with the aid of a customised bed of repulsorlift devices [X-Wing: The Krytos Trap].
The Executor in formation with the ISDs of Vader's personal fleet, approaching the planet Hoth.
Sublight thrusters of the first and second banks: starboard and port sides. [STAR WARS Chronicles; TESB movie frames]
Direct ventral view of the first and second thruster banks and surrounding assemlby.
Oblique ventral views of all three thruster banks of an Executor-class ship whose construction is almost complete. [SW Chronicles]
Detailed view of the innermost starboard thruster of what appears to be the second thruster bank. [SW Chronicles]
Executor may be able to dock on a planetary surface, with special preparation. [Marvel SW #63]
According to The STAR WARS Sourcebook there were four Executor-class vessels in service in the time immediately following the Battle of Yavin in A New Hope. By the time of the Battle of Endor, four years later, their success had led the Imperial Navy to construct many more, acting as standard command vessels throughout the Galactic Empire. Piloting a stolen shuttle to Endor, Han Solo was unsurprised to see the Executor in orbit, acting as the command station for processing security clearances for passage through the deflector shield protecting the new Death Star. When Luke Skywalker announced that Vader was present, Solo responded “Now don't get jittery Luke; there are a lot of command ships.” Clearly the Executor's siblings were relatively abundant by that time, or at least no longer rare. Most were probably put to use as flagships for Grand Admirals, Grand Moffs and important Moffs. For instance, the Black Sword Fleet near Farlax sector was led by three Executor-class command ships.
For further details on the treatment of continuity, refer to Continuity, Canon and Apocrypha.