How the Death Star Works

The Death Star is the size of a small moon. See more Star Wars pictures.
Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved.

There is no question that the last few years of world history have seen a fair share of chaos and disorder. With so much global unrest, governments worldwide are struggling to devise new methods to maintain order. The Galactic Empire's solution to order is the Death Star.

Simply put, the Death Star is the most ambitious space station project in Galactic history. It takes more than a million military personnel to run this station, which is the size of a small moon.


But the Death Star is no moon. Despite its size, the Death Star can still travel at superluminal velocities just like spacecraft with only a fraction of its mass. But the real power and purpose of the Death Star lies in its Superlaser. The Death Star's Superlaser is capable of firing a beam of directed energy powerful enough to completely destroy a planet of any size! Needless to say, nothing quells chaos and disorder faster than the threat of total planetary annihilation.

The Death Star represents the absolute pinnacle of military engineering and technology. In this article HowStuffWorks will look at the Death Star inside and out, examine the fascinating history behind this powerful military and political tool, discover other incarnations of the Death Star and learn about what really happens when you blow up a planet.





Death Star Basics

A routine TIE Fighter patrol guards the Death Star.
Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved.

The Death Star's main purpose is to function as a mobile platform for its main weapon - the Superlaser. The Death Star's structure is basically an enormous housing for the Superlaser and the reactor that powers it.

It takes a lot of technicians to operate and maintain the Superlaser. And although it's the most powerful weapon in the galaxy, it's completely defenseless if attacked directly. So the Superlaser also needs military support to defend it. To address these issues, the designers of the Death Star equipped this enormous housing to serve two purposes: It is both a mobile weapons platform and a fully operational battle station.


Of course in order for the Death Star to be a real threat, it has to be mobile. To accomplish this the Death Star features a complex network of real-space ion engines and hyperdrive field generators that allow it to travel like any other interstellar space craft.

So basically the Death Star is made of four major components: the battle station, the Superlaser, the propulsion system and the hypermatter reactor that powers it all. Let's look at all of these components.


The Death Star Surface

A Turbo laser turret on the Death Star's surface tracks enemy starfighters.
Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved.

In the original design, the Death Star measures 120 kilometers (roughly 75 miles) in diameter. A huge equatorial trench splits the surface of the station into two hemispheres. This trench is used to house many of the Death Star's main systems:

  • Landing bays
  • Drive thrusters
  • Sensor arrays
  • Tractor beam systems

In addition to the main trench there are two supplementary trenches halfway between the equator and each pole that are used mostly for maintenance and secondary reactor ventilation.


There are thousands of weapons emplacements scattered all across the Death Star's surface, including:

  • 10,000 turbolaser batteries
  • 2,500 laser cannons
  • 2,500 ion cannons
  • 768 tractor beam projectors

Most of the surface of the Death Star is covered with buildings of varying size and purpose, so that it closely resembles a sprawling metropolis. Now let's look inside.


Inside the Death Star

Large shafts like these are typical of the Death Star's inner decks.
Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved.

Most of the space inside the Death Star is devoted to systems required to maintain the Superlaser, propulsion system and hypermatter reactor. Of course the largest space is the main reactor chamber at the core of the Death Star. The rest of the interior is made up of a honeycomb of decks for personnel and equipment. This space is designed with two separate layouts each with a different source and orientation of artificial gravity.

The "layer" closest to the surface is laid out in a series of concentric decks with artificial gravity generators pointing towards the Death Star's core. Below this are thousands of levels of sprawling stacked decks dotted with vast, deep shafts that all link to the reactor's main chamber. This section of the Death Star makes up the bulk of the interior and has gravity pointing toward the station's southern pole.


The two interior sections of the Death Star are divided into 24 zones, 12 per hemisphere. Each zone is organized into six sectors:

  • General
  • Command
  • Military
  • Security
  • Service
  • Technical

All the sectors are run by an officer who answers to a zone captain, who controls his or her zone from a zone bridge. The entire Death Star command structure answers to one Death Star Commander. The Commander operates from the overbridge. The overbridge is the nerve center of the Death Star and is located just above the top edge of the Superlaser dish. Governor Tarkin was acting commander of the first Death Star. The station's military forces fell under the command of General Tagge (ground forces) and Admiral Motti (naval forces).


The Superlaser

The main cannon and eight tributary lasers fire beams that converge at the outer perimeter of the Superlaser dish in an amplification nexus.
Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved.

If you've ever burned a leaf with a magnifying glass you understand the basic principle behind the Superlaser. When a magnifying glass is held at the correct angle between the sun and a leaf, the sunrays are focused through the lens. These rays intersect under the lens and at the point of intersection a beam of heat is created that burns the leaf. The sun is the source of power and the lens is the focus.

The Superlaser has a massive lens built around a huge synthetic focusing crystal. The lens is known as "the Eye" and is surrounded by eight tributary lasers. There are also four back up lasers in case any of the main eight tributaries fail. All of the tributary lasers can be angled for targeting. This allows the Death Star to aim the Superlaser within a certain field of fire without having to turn the entire station. The main cannon and eight tributary lasers fire beams that converge at the outer perimeter of the Superlaser dish in an amplification nexus. A main beam then blasts from the nexus to the intended target.


The Death Star's Superlaser derives power directly from the hypermatter reactor. The lasers convert and focus the full power of the reactor to create the beams. So going back to our magnifying glass example, the Superlaser is like a series of large magnifying glasses focusing the entire power of the reactor (which is like a small sun) into one huge beam to destroy a planet, rather than a few rays of light to burn a leaf.

Firing the Superlaser

Alderaan was the only populated planet ever destroyed by the Death Star.
Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved.

There have only been two instances where the Death Star fired its Superlaser at full power while targeting a planetary body. The Death Star's first test firing destroyed the remote and uninhabited planet Despayre. The first Death Star was built in orbit around Despayre, making it an ideal choice to test the Superlaser's power as well as destroy the evidence of the Death Star's construction. The second instance was the highly publicized destruction of Alderaan.

The Superlaser's power needs to be recharged between blasts, limiting it to only one planet-destroying beam per day. The output of the Superlaser can however be scaled to fire at smaller targets such as capital ships. The Superlaser can produce a scaled beam at a recharge rate of one per minute.


It takes 168 Imperial gunners to operate the Superlaser. There are 14 gunners manning each tributary laser while the remaining crew operates other systems. The Superlaser can only be fired under direct orders from the station commander or the Emperor himself.

Power and Propulsion

Photo courtesy NASA/JPL/Space Science Institute

The greatest challenge in designing the Death Star was not creating a cannon big enough to fire a beam that could destroy a planet, nor was it creating a battle station the size of a small moon. The greatest challenge was always powering a cannon big enough to fire a beam that could destroy a planet and moving a battle station the size of a small moon. The answer to both of these problems was solved with the invention of the hypermatter reactor.

The hypermatter reactor is the heart of the Death Star. The Death Star's hypermatter core is based largely on early Sienar Systems hypermatter implosion core that was the power source of the Confederacy of Independent Systems' Great Weapon (the early inspiration for the Death Star -- more on this later). Little is actually known about the details of the highly classified reactor design, but we do know that it is a massive fusion reactor fed by stellar fuel bottles that line the periphery of the main reactor chamber.


The Death Star's real-space propulsion system is made up of a network of ion engines that use converters to transform reactor power into thrust. The engine thrusters are primarily lined along the equator of the station.

Hyperspace travel is made possible with linked banks of hyperdrive field generators. Each bank contains 123 hyperdrive field generators. They are all tied together into one navigational matrix that is controlled from the overbridge.


Life on the Death Star

It takes more than a million people to operate the Death Star and there is room for over a billion people on board. There are always at least 1,161,293 Imperials stationed on the Death Star at any given time. The standard complement of personnel includes:

  • 265,675 Station crew
  • 52,276 gunners
  • 607,360 troops
  • 25,984 Stormtroopers
  • 42,782 ship support staff
  • 167,216 pilots and support crew

The station also carries:


  • 7,200 starfighters
  • 4 strike cruisers
  • 3,600 assault shuttles
  • 1,400 AT-ATs
  • 1,400 AT-STs
  • 1,860 drop ships.
  • a variable number of support, recon and assault droids

Tours on the Death Star last at least 180 days and usually much longer. Personnel are often in deep space without leave for months at a time, and since the location of the Death Star is always classified, contact with family or friends is strictly prohibited. This can make life on the Death Star very difficult. To ease the burden of this duty the station is outfitted with many civilian amenities. The general sector of each zone in the Death Star has a park, shopping centers and recreation areas that include restaurants, a cinema and fitness centers.


Death Star History

This is NOT the Death Star. Vader and Palpatine survey the CIS's recently captured "Great Weapon."
Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved.

The Death Star battle station was the brainchild of Imperial bigwig Grand Moff Tarkin. It was the centerpiece of Tarkin's Doctrine of Fear proposal that created sweeping reform in the structure of the Empire. It was also the final step in solidifying the Emperor's total authority.

The largest change to the Empire made by the Doctrine of Fear was the dissolution of the Imperial Senate. Tarkin's policy put power directly in the hands of the regional governors. The governors, who ruled over several planetary systems, now answered directly to the Emperor under the Doctrine of Fear. This new organization greatly reduced the bureaucracy in the Empire and greatly increased the power of regional governors like Tarkin.


Opponents to the Doctrine of Fear (and there were many in the Empire) claimed that this new policy would rip the Empire apart and that planets would revolt without direct representation in the Senate. Tarkin's answer to any potential dissonance was the Death Star.

Tarkin intended to make an example of a rebellious system as soon as the Death Star was capable. He believed that after the total annihilation of a planet, fear would spread throughout the galaxy and maintain order.

The development and construction of the Death Star had begun long before the first debate ever took place about the Doctrine of Fear. In fact, the Doctrine of Fear was ratified by the Emperor the very same day the second successful firing of the Death Star destroyed the planet of Alderrann.

Visionary scientists and engineers like Qwi Xux, Tol Sivron and Bevel Lemelisk were conscripted by the Empire to develop the space station. They all worked in a top secret facility, code-named Maw, hidden deep in one of the most inhospitable regions of the galaxy. A prototype Death Star was built at Maw but was little more than a spherical frame with an untested Superlaser. It was much smaller than the Death Star would eventually be and had no propulsion system.

The construction phase of the Death Star project took place in orbit around the planet Despayre and was primarily handled by defense contracting company Sienar Systems. Sienar had worked on a prototype of a similar space station many years earlier for the CIS, was contracted by Tarkin to do work on the Death Star project. (It should also be noted that Sienar Systems CEO Raith Sienar was "coincidentally" an old friend of Grand Moff Tarkin).

For years, the Empire used prison labor to mine Despayre for materials. Prison laborers also handled the more menial and dangerous aspects of the station's construction.

The inspiration for the Death Star came from a Separatist super-weapon called the Great Weapon. The Great Weapon was a moon sized-space station with a large laser cannon developed by the Trade Federation, Geonosians, and Techno-Union for use in their war against the Old Republic. It was never put to use and was captured by the newly formed Empire after the Clone Wars. The Great Weapon was never completed.

The original Death Star was destroyed in the Battle of Yavin by rebel pilot Luke Skywalker. Skywalker fired a proton torpedo into a reactor vent shaft. The ensuing chain reaction caused a critical overload of the reactor, destroying the entire station and killing everyone aboard.


Death Star II

Death Star II
Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved.

After the destruction of the first Death Star, the Empire immediately began building a second Death Star. Death Star II was placed under the command of Moff Jerjerrod and was a larger (160 km/99.5 miles in diameter) more powerful version of its predecessor.

Many of the design flaws of the first Death Star were corrected in Death Star II, including its Achilles heel -- the thermal exhaust ports. Instead of relying on several large vent ports that led directly to the station's main reactor, Death Star II was designed with network of variably angled millimeter-wide heat dispersion ducts. This design made it impossible for a projectile to reach the reactor via the vent system.


Another costly oversight was corrected in the layout of the new stations defenses. The original Death Star was only designed to repel an attack from large capital ships. Because of "loose" net cast to catch attackers, Rebel fighters were able to easily penetrate the Death Star's defense grid. The design of Death Star II almost doubled its surface defenses and triangulated them so that both capitol ships and fighters could easily be gunned down.

Death Star II was designed with:

  • 30,000 turbolaser batteries
  • 7,500 laser cannons
  • 5,000 ion cannons

The Death Star II also featured a larger and more powerful Superlaser that was capable of firing more frequently and more accurately.

Death Star II was under construction in orbit around the forest moon of Endor. While under construction, the new Death Star was protected by a large energy shield, projected from the nearby moon. Despite this, the Rebel Alliance destroyed the unfinished Death Star II in the Battle of Endor.


So What Happens if You Blow Up a Planet?

There has been a lot of controversy surrounding the Death Star. Besides the obvious issues associated with destroying an entire planet, there are also the concerns for the effects that the destruction of a planet would have on other planets in the same system.

So what does happen to other planets in the same system as a planet that is completely destroyed by the Death Star?

To answer this question HowStuffWorks went to F. Todd Baker, Physics Professor at the University of Georgia Department of Physics And Astronomy. Here was his answer:

Regarding the moons of a planet, the subsequent motion would be determined by what happens to the debris from the planet. Of course the "destruction" of a planet does not mean that its mass disappears, it is just redistributed. A couple of scenarios:

  1. Suppose the earth became a cloud of debris with 10 times the radius of the present earth. Then this cloud would continue orbiting the sun as it does now (the length of a year would be the same) and the moon would continue orbiting this cloud as it does the earth now (the length of a month would be the same). This supposes that the cloud of debris were roughly spherically symmetric.
  2. Suppose that the annihilation were so catastrophic that the debris completely dispersed in a spherically symmetric way. As soon as some of the debris passed the moon's orbit, the gravitational force on the moon would begin decreasing and the moon would change its orbit in a continuous way until, finally, it would be orbiting the sun in an orbit more or less the same as the earth's current orbit. All the debris would also end up orbiting the sun in many different kinds of orbits much as asteroids and comets do today; some would end up in orbits which resulted in their hitting the sun.

For more information on the Death Star and related topics, check out the links that follow.

Lots More Information

Related Articles
More Great Links

  • The Star Wars Technical Commentaries -- Death Stars
  • The Boards: A History of the Death Stars -- Another TalonCard Project (TM)
  • NASA Photo Journal
  • Sam's Archive: How To Destroy the Earth
  • Death Star Firepower
  • Star Wars Databank: Admiral Motti
  • Star Wars Databank: Death Star
  • Star Wars Databank: Death Star II
  • Star Wars Databank: The Empire
  • Star Wars Databank: General Tagge
  • Star Wars Databank: Grand Moff Tarkin
  • Star Wars Databank: Moff Jerjerrod
  • Star Wars Databank: Superlaser
  • UGA's Department of Physics and Astronomy "Ask The Physicist"