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After asking this question and reading more in the Wookiepedia and thinking about how everything in Star Wars seems to be just so much bigger than life (or most imaginations), I started thinking about the Imperial ships.

I read somewhere that the original Death Star had a crew of over 1.5 million on board. The crew complements for Imperial Star Destroyers and Superstar Destroyers are also quite large, although not as large as the Death Star. Just moving the crew from various planets onto the ship to fully staff it would require an amazing feat of logistics.

Also there's the matter of the amount of material used in such large ships. It would be a significant amount to take out of any one planet, but considering the materials needed, that would involve mining the materials on many planets and transporting such large loads to a construction site. Supposedly the Death Star II was built in only a few years, after the first one was blown up and it was also much larger.

The Death Star II was also fully operational with extremely large sections of it uncompleted or not even started.

All this raises two questions:

1) Are the Imperial ships bigger than they need to be?
2) Is it even possible, considering logistics of construction and staffing, to be able to create such large ships?

I read about the Darksaber, which is essentially a superlaser like the one in the Death Star, but without all the extra mass around it. Since the Death Star is essentially an instrument of destruction, why does it need do do more than support and protect the superlaser? And why do the Star Destroyers need to be so big? While we can say that's for troop transport, considering the size of the destroyer and the amount of troops it could carry, can it move that many troops down to a planet quickly?

In short, are the logistics possible to make ships this large possible and is there really a need for them to be as large as they are?

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Maybe they are all from Texas? –  Xantec Dec 13 '11 at 3:18
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It's because size matters –  BBlake Dec 13 '11 at 3:33
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I'm still waiting for someone to say it's overcompensation. –  Tango Dec 13 '11 at 3:38
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Have you watched the start of Spaceballs? –  Wikis Dec 13 '11 at 5:47
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Why would you mine raw materials from a planet? That just involves dragging stuff out of a gravity well, for no reason. Meanwhile, out in space, asteroids are just flying around, ready for the taking. –  Daniel Roseman Dec 13 '11 at 9:43

5 Answers 5

up vote 74 down vote accepted

I think a good place to start in attempting to answer this question is to look at the most comparable vessel we have today, which would be a large nuclear sub or an aircraft carrier (supertankers may be larger, but they're designed for cargo). Aircraft carriers can be much larger than subs, so let's start with that.

The main purpose of an aircraft carrier is obviously to carry aircraft and provide a mobile platform from which to launch and retrieve those aircraft. So naturally the aircraft carrier will have a flight deck. If we take a look at the largest supercarriers today, the Nimitz-class, we can see that this class of carriers has 4 catapults for launching aircraft, and 1 set of arresting cables for landing. Besides that, it also has a helipad for launching and receiving helicopters and 3 hanger decks carrying up to 90 aircraft, supported by 4 massive elevators. And these consitute all the sections of the carrier used for its main mission.

But there's still at least 60% of the ship that's not accounted for. So what's in the rest of the ship?

  • A big one in any vessel is going to be the engine room/power plant and propulsion system. The Nimitz class uses 2 Westinghouse A4W nuclear reactors + 4 steam turbines. Not sure about the proportions on the Nimitz class, but on some nuclear icebreakers, the engineering sections can comprise about one-third of the ship.
  • There's the island, which serves as a control tower/bridge for directing aircraft operations and commanding the ship. This is a vital section of the ship, but it consitutes a relatively small part of the ship's total volume.
  • Cargo space for carrying fuel (for aircraft), munitions, food, and other logistical materials. A carrier this size carries 3.3 million gallons of aviation fuel. It also stores enough food to feed 6000 people for 70 days. Including crew living quarters, there are 4000 compartments/spaces aboard with 2500+ telephones and 3000+ TV sets. To add to this logistical load, the carrier distills 400,000 gallons of water and serves 18,000 meals per day.
  • There's also a 2,250 ton airconditioning plant, 1000+ miles of cable, 5 dentists, 6 medical doctors, a 53-bed hospital ward, a barber shop, a newspaper, an on-ship radio station, a chapel with 3 chaplains, and a post office that processes 1 million pound of mail each year.
  • Then there's all the built-in armament and structural components that make up the carrier (60,000 tons of structural steel).

Basically, a supercarrier is a small (heavily armed and fortified) floating city. Now scale that up to a weapon with the ability to destroy a planet with a single blast.

We can't calculate how big a crew is really needed to operate and maintain a weapon as impossibly powerful as the Death Star, but we do know that it would at least need to have all of the functions of an aircraft carrier, since the Death Star is a moving weapons platform, and it's defended with both point defenses and a fleet of tie-fighters and possibly other attack ships.

And if you have a big vessel, you'd need a much larger fleet of fighters to defend it. Let's say there are 10,000 tie-fighters on the Death Star II. The Nimitz-class has 2800 aircrew onboard for a maximum of 90 aircraft. That means the DS2 would need at least 311,000 aircrew. If we assume that the same ratio of aircrew to ship's company exists, then that would require over 355,000 engineers, maintenance crewmen, ship's crewmen and other support personnel. It doesn't add up to 1.5 million, but it does make the figure seem less outrageous.

And the more you scale up, the greater the logistical resource needs stack up, especially if the vessel is going to be on multi-year missions across the galaxy. For psychological and social reasons, you'd need to have even more crew comforts and civic infrastructure, like libraries, entertainment centers, living areas, schools, gyms, hydroponic farms, etc. You'd also have more need for support personnel from electricians and mechanics to nuclear engineers and scientists to security officers, forklift operators and janitors. Conveniently, a large crew and ship will also serve to reduce the psychological stresses of feeling isolated and trapped during extended space voyages.

And of course, the Death Star is going to be much stronger and more fortified than a supercarrier. It not only has to withstand the vacuum of space and its own gravitational stresses, but it has to have the forcefield generators and physical armor to withstand space-age weapons. Ships use multi-layered hulls that are partitioned by water-tight bulkheads. You'd expect the Death Star to be similarly-designed.

And if the above don't account for the epic scale of the empire's vessels, also consider that engineering systems are similar to bureaucracies. The bigger they get, the bigger and more complex they need to be just to manage itself. If you add 10,000 more rooms, you need to add 20,000 times the wiring, ducts, corridors, structural reinforcements, life-support systems, powerplant capacity, etc.

So with all of this infrastructure (and the further infrastructure to support the infrastructure), it quickly adds up. How many people do you need to operate enough powerplants to power a small moon (one that's not just colonized on its outer surface, but its entire inner volume)? How many people to crew the oxygen/water/food plants? How many people to operate/maintain/repair all of this machinery? 1.5 million actually starts sounding a bit low.

And that concludes my ridiculously long answer for an epic-sized question

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@TangoOversway: it seems like quite a feat to design and build something of this complexity in less than 2 decades. I mean, these days they can put superskyscrapers up wtihin 2 years of beginning the blueprints, but the logistics of putting together such a large and complex engineering system... well, they must have some of the galaxy's finest project managers to be able to procure materials, manage supply chains, handle thousands of different subcontractors, etc. with that level of efficiency. –  Lèse majesté Dec 13 '11 at 6:11
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I also think it's a little weird that you never see any appropriately large cargo ships or construction vehicles around the half-completed DS2. You'd at least expect to see a large supply depot/staging area orbiting the Death Star where supply ships can unload the huge amounts of parts and raw materials needed for construction. The DS2 seems like the neatest, most peaceful/unbusy construction site in the galaxy. –  Lèse majesté Dec 13 '11 at 6:16
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The logistics of creating such a massive work are simplified when it can be constructed in microgravity. Tractor/presser beams also help, as does the ease with which the Empire can set up on-site factories. –  Jeff Dec 13 '11 at 14:27
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@Lèsemajesté - you need a significantly smaller project management skill when your method of motivation includes "what till Lord Vader hears of your performance revew" –  DVK Dec 13 '11 at 15:44
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@Lèsemajesté - don't mention things you would like to see added. Lucas will see it and decide to make another version, this time with supply support ships around the near-complete death star! –  Justin C Dec 13 '11 at 19:31

According to the Galactic Republic entry on Wookieepedia, in 21 BBY the Republic had 1.3 MILLION planets in it. I think it's a safe assumption that the vast majority of these worlds were carried into the Empire. Given these numbers I would say that the Empire has massive resources to draw on.

I think there are two major factors related to the size: Intimidation and Survivability.

The intimidation factor can easily stop most issues before they even arise. Remember the attack on Death Star II: "It's a TRAP!!! The Rebel Fleet's attack was intended to be a surprise assault against a lightly-defended, half-constructed, supposedly inoperable station. Instead they ended up in a pitched battle against the Imperial Fleet. My guess is that had they been aware of the Imperial Fleet they would have not attacked or at least tried a different strategy. My guess is that the Rebel Fleet wouldn't have even attacked the Imperial Fleet head on.

The Survivability factor is the idea that a larger, more heavily armed ship will stand up better in a battle then a larger number of small ships. For example, the SSD in an open space engagement probably wouldn't have been destroyed (remember, it wasn't so much blown up as it crashed into the DSII). My guess is that even with its bridge destroyed, it probably would have remained combat effective. Also, a larger ship provides more hangar space for TIE-fighters, which seem to be the most effective anti-fighter force the Imperial Fleet has. They have more surface area, allowing them to mount more, larger weapons. Another factor related to size is that items like the Death Star (I and II) were meant more as deterrents then as actual weapon platforms. DSI would have been virtually immune to attack from a conventional fleet; I'll hypothesize that had DSI been attacked by the same Imperial Fleet that was present at Endor, it would have prevailed. My guess is that the reason DSII was destroyed was wasn't a design issue but a doctrinal issue: Imperial Admirals refused to accept the potential of fighters in a battle. The mentality which lead to large warships in turn negates the value of small fighters, reducing them to either fast, fragile defensive fighters or cumbersome bombers. If the Imperial Admirals considered the situation of DSII from the rebels perspective of a fighter attack against the core, they probably would have oriented their fleet to screen the hole.

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The Trigon One was small compared to its power. When the leader of the Fromm gang saw it, he was disappointed at its size because he wanted something massive and intimidating. When his son commented that miniaturization is the future, he threatened to miniaturize him. (Droids, episode 2).

I believe the imperial ships too, are large for the same reason; which is also the same reason communist regimes goose-step thousands of soldiers and parade nuclear warheads: as a spectacle of glory and intimidation.

As for the logistics, it is possible to capture a mineral-rich asteroid, mine it for material and gradually build the station right around it. Droid labor is cheap -- note that even the Trade Federation had millions of them. The zero gravity environment makes things even simpler.

The crew size cannot be explained, unless the destroyers (and the Deathstar) double as mobile military bases. I've not read much extended universe material, but imperial troops almost always seem to be based on ships, rather than ground bases. This might be why the ships are so big.

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Maybe it's part of some economic stimulus program? :) –  Chris B. Behrens Dec 13 '11 at 4:58
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But of course it was: thedialecticalplaya.com/wp-content/flagallery/… –  HNL Dec 13 '11 at 6:24
    
That is awesome... –  Chris B. Behrens Dec 13 '11 at 14:37

There are several limits on ship designs in any universe:

  • Material Strengths
  • available crew
  • available funds
  • political will
  • construction time

Crew

The available crew issue is pretty big in Star Wars... some ships have hundreds of thousands of crewbeings. (Executor is over 270,000 beings...) It's 19,000m long. That's several miles. Assuming that each individual needs some 50 cubic meters of open space and/or quarters for sanity's sake, that's only 1,400,000 cubic meters - a 112m cube - so the crew numbers are pretty low for the roughly 3 cubic kilometers (3,000,000,000 cubic meters). And even given a fleet of 500 of them, that's still under a 0.1 billion people... well within the capability of Coruscant to supply the crews for even given US current rates of volunteers for naval duty.

Structure

It has an acceleration listed as 1280 G's... 12km per second per second!

With those kinds of stresses, all known normal materials in our universe simply will fail... So it has to work by some form of drive that doesn't impose that force by direct mechanical transfer.

Once you posit drives that don't use mechanical transfer, instead imposing an area affect acceleration, size ceases to be a mechanical limitation, as long as the drive fields don't tear it apart.

Officially, star wars drives work by mechanical transfer with artificial gravity preventing turning crew into red paste on the wall... ... but meaning the ships are too large because the stresses involved are unreasonably high.

Price

The Empire can afford to waste the money by all canon sources. Not an issue.

Political Will

Obviously, the Empire has the political will.

Big ships show that, and real world autocracies are very likely to push ship designs to the larger side of what's possible. It's happened a lot in naval history (in the 1800's, plus WW I and II), so a megalomaniacal leadership like we see in Tarkin, Mott, and Palpatine would probably be prone to "A few big ships are enough to scare everyone into submission" thinking.

Construction Time

We know it took many years to build the Executor - construction times of decades are long, but not really overly exaggerated. Modular builds did not make the USS Reagan terribly fast - she took 4 years from awarding to laying the keel, another 3 years from first laying of the keel until launch, and over 2 more to be commissioned and accepted. A decade, for a ship only 333m long... And many components were in construction before the keel was actually laid down.

Discussion

By comparing to the biggest warship afloat, we have 2 indicators of her being oversized...

1) crew volume density. A Nimitz-class carrier is 6000 crew (including aviation wing) in 0.3x0.08x0.06, roughly a prism, so volume 1/2 that... about 0.00072 cubic km, or 720,000cubic meters. That's roughly 1 crewman per 60 cubic meters... Which, even cutting by a factor of 100 for the SW level of automation, means she's under-crewed by a couple orders of magnitude.

2) material strength... the executor should snap her structure the first time she goes under power given the lack of sufficient handwavium.

Even comparing to the smaller Imperial Star Destroyers, which are described in canon as costing more than a major world's annual budget, and are 1.6km long (about 0.4 wide, and 0.1 thick, roughly a pyramid, for about 0.01 cubic km (10,000,000 cubic meters) - roughly 130 times the size of a Nimitz Class carrier, and a similar role. But they have crew and troops totalling about 45,000 people, only 8x that of a Nimitz class...

And, like the Executor, the ISD's should be bending themselves into pretzels with their 2000+ G's.

So, yes, they're unrealistically large. Not for the size alone, but for the listed performance coupled to the size, they are physically improbable given the central drives.

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An excellent analysis. But we don't know the hull and wall thickness or the sizes of the supporting members in these vessels. What if those large unoccupied spaces you've pointed to are packed full of reinforced handwavium? And I'm sure the Star Wars universe has something similar to structural integrity fields and inertial dampeners. –  Lèse majesté Dec 15 '11 at 21:46
    
@Lèsemajesté There are limits on materials strength... the needed handwavium to make ships that big survive even 200g's, let alone 2000, involve using fields to accelerate everything, rather than the neatly portrayed H-K hyper-efficient ion drives of canon. –  aramis Dec 15 '11 at 23:56
    
Well, it's pretty much impossible for an ion drive or any conventional propulsion system to achieve superluminal speeds. Any superluminal drive would have to bypass relativistic effects/barriers. But even assuming if this weren't so, why couldn't a vessel of that size be strong enough to endure that level of acceleration given great enough hull thickness? –  Lèse majesté Dec 16 '11 at 0:14
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Not really... (1) the HK drive is the sublight drive, not the superluminal. (2) 2000G's assymetric acceleration on pretty much anything results in shearing forces... 200G's, by the way, is peak automotive impacts - 200MPH to 0 by hitting an obstacle - and the effect is devastating to the structure. Sure, some small objects survive near-uniform 50,000G loads (bullets, mostly), but for a viable spacecraft, with sidewall thicknesses under 4m (which can be estimated by window wells), those sidewalls need to be accelerated other than by the HK drives in the back. –  aramis Dec 16 '11 at 0:22
    
2000Gs but it still took about a quarter of the movie to get around that one planet to take a shot at the Rebel base. –  Oldcat Jul 16 at 21:24

I'm surprised that no-one's mentioned the Tarkin Doctrine.

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