The Magnetic Accelerator Cannon – or MAC gun – is the standard main weapon of all UNSC cruisers, destroyers and frigates, and much larger versions are the main weapons onboard UNSC orbital defense stations. The MAC gun is stated as the UNSC's most powerful non-nuclear weapon.
All Magnetic Accelerator Cannons are built into the structure of a ship or weapons platform. Thus, to aim the cannon, the ship or the platform must maneuver to be facing the target. Both shipboard and platform versions generally require an AI to aim the cannon, as the slugs fired are unguided. Even taking into account the high speed of the shots and the supreme accuracy with which an AI can aim them, they are highly inaccurate as battles usually take place across 100,000 km or more, allowing Covenant vessels to dodge them. From what is know about the MAC gun, it may be possible to build one with a cannon, superconducting magnets, a lot of power, and a magnetic artillery shell.
Standard Magnetic Accelerator Cannon
The MAC gun uses a linear acceleration system, comprised of several superconducting coils which generate a series of power magnetic fields that continually add velocity to a ferric projectile until it leaves the shaft of the MAC cannon carrying a extremely high amount of kinetic energy. The coils are powered by a series of capacitors that store the tremendous energy necessary to accelerate a heavy projectile to relativistic speeds.
Common shipboard Magnetic Accelerator Cannons are capable of accelerating a 600 ton ferric projectile with a depleted uranium core to 10% the speed of light, or roughly 30,000 kilometers/s (18,628 miles/s). The main drawback to the shipboard MAC gun is the large amount of time it takes for the capacitors to reach full charge. This drawback has proven to be significant in combat against Covenant warships, since it has been shown that it requires several ship-scale MAC rounds to penetrate Covenant shields.
An experimental version of the MAC gun has been developed that is able to fire three successive rounds on one charge. A prototype of this weapon was mounted on the UNSC Pillar of Autumn. MAC guns exist on many different scales, ranging from the massive Mark V "Super" MAC guns on board orbital defense platforms, to common shipboard MAC guns, and even down to the "Gauss" cannon mounted on board the Warthog LRV.
Super Magnetic Accelerator Cannon
Super MAC guns are loaded on defense platforms orbiting Reach, Earth, and other strategic locations that must be protected, and are much more powerful than normal MACs. The Orbital MAC guns (nicknamed "Super MAC" or "The Big Stick") are capable of accelerating a 3000 ton ferric-tungsten round to 40% the speed of light(74,512.9 miles/s) and can reload in five seconds. These weapons are able to destroy a Covenant warship with a single shot, literally shattering a fully shielded Covenant vessel. They are are commonly placed in geosynchronous orbit around a planet, often over the location they are named after.[1]
The one weakness of the orbital MAC guns, at least on Reach, is that the power stations that power them are located on the surface of the protected planet, and are thus susceptible to attack from Covenant ground forces. The fanatical nature of Covenant engagements have also presented a problem, since the Covenant are more than willing to sacrifice a number of ships in order to destroy one platform. This tactic was seen during The Battle for Reach.
The MAC cannons can be found throughout the Halo universe, and play critical roles in many battles. The use of the MAC gun proved decisive when the Covenant fleet descended to Earth at the beginning of Halo 2, and was used as early on as Master Chief's first encounter with the Covenant, in which it was used to blow a hole into the ship through which Spartans could access.
Speculation
There may be different size MAC guns to different ship classes e.g. the Frigate may have a smaller or less powerful MAC gun than one fitted to say a Super Carrier or a Marathon-class Cruiser but it is unknown. But it is most likely that a ship could hold more than one 'large' MAC gun e.g. the Marathon-class Cruiser, it does not state that it holds 3 MACs so it is most probable it only holds one or else what would been of the need for the new type that was fitted on board the Halcyon-class Cruiser?
Likely Position of MAC cannon on a Halcyon-class Cruiser
While the specific location of a Halcyon-class cruiser's MAC cannon is not known, it is most likely near center of the ship. The destructive capability of a MAC cannon is such that it can completely destroy any human vessel, and severely damage an unshielded Covenant vessel. In the Halo novels it is said that a UNSC ship's MAC cannon could obliterate a human built vessel with just one shot and severely damage an unshielded Covenant vessel.
Many believe that the MAC launch tube is located near the underside of the ship, where there are three large plates. However, it is more likely that the tube is located along the entire length of the ship. Logically, the multiple powerful magnets needed accelerate a 600 tonne slug to 0.1c requires an exceptionally long tube, allowing for many magnets to affect the projectile. The huge length 1.17 km length of the Pillar of Autumn would facilitate this, making the most likely muzzle location of the MAC tube to be located at the protrusion at the ship's bow.
Further supporting the hypothesis of a tube running through the entire ship is the structure and design of Cairo Station. After exiting the cargo elevator, the player can look up and observe the Super MAC platform in action. The slug travels the entire length of the tower, and exits at the "top." Later in the level, the player can notice the loading zone of the slugs at the base of the launch tube.
Known Orbital MAC Geosync Platforms
Naming Theory
One theory on the naming of of MAC's is that they are named after the place they orbit above. For example the Cairo, Athens, and Malta all orbit above the Mediterranean Area.
Sources
- ^ Halo: The Fall of Reach, pages 296/297