Pillar of Autumn

UNSC Pillar of Autumn - a modified Halcyon-class light cruiser

A dozen Covenant superior battleships against a single Halcyon-class cruiser. Given those odds, I'm content with three...make that four kills.
~ Cortana, Shipboard Smart AI of the UNSC Pillar of Autumn


The Halcyon-class was a type of light cruiser employed by the United Nations Space Command Navy between 2510 and 2553 CE. They were quite expensive to build and maintain due to their unique structural design and had short service lives due to this. There were also concerns about their tactical viability as they would sacrifice speed & manoeuverability for durability and had limited firepower at stock configuration compared to other warships in the same size range (though expensive modifications could boost their firepower tremendously). However, during the course of the Human-Covenant War of 2525 to 2553, the Halcyon-class and their successor class - the Marathon - would prove to be surprisingly effective (high operational costs notwithstanding). In the post-war period, UNSC Naval Command would commission the Autumn-class line of heavy cruisers. The design of this class borrowed heavily from the modified Halcyon-class Pillar of Autumn, which was sacrificed during the Battle of Halo Installation 04 in 2552.

Powers and Stats

Tier: Likely 9-A to 8-C with point-defence guns and Archer missiles | Up to 7-C with main MAC | 7-B with nuclear missiles | 6-B to High 6-B via self-destruct

Name: Halcyon-class Light Cruiser

Origin: Halo

Classification: Starship | Light Cruiser

Users: UNSC Navy

Length: 1,170 metres

Width: 352 metres

Height: 414 metres

Material: Mostly Titanium-A plating on the exterior

Needed Prerequisite for use: Trained crew, "Smart" AI needed for optimal use of various armaments and accurate long-range Slipspace jumps

Terrain: Space, Atmosphere

Attack Potency: Likely Small Building level+ to Building level with point-defence guns and Archer missiles (Refer "Armaments" section. It should be noted that Seraph fighters are equiped with energy shields which are far more powerful than the personal energy shields of the likes of John-117 and Thel 'Vadam) | Up to Town level+ with main MAC gun (Refer "Aramaments" section. On the highest power setting, a fired projectile can have Kinetic Energy of 2.7e+14 Joules) | City level with Shiva-class nuclear missiles (Usually fitted with the 30 Megaton HAVOK warhead) | Country level+ to Large Country level via fusion drive self-destruct (Refer to the note at the bottom of the page)

Speed: Unknown atmospheric and real-space speeds, Massively FTL+ travel via Slipspace, High Hypersonic to High Hypersonic+ attack speeds with various armaments

Durability: Likely Small Town level (The Pillar of Autumn has taken hits to non-vital sections from Covenant Energy Projectors, which can slag large buildings with a single shot, and carried on fine. However, a single well placed hit to the engine/power sections would have easily crippled her)

Range: Up to 3,000 km (The Commonwealth, a UNSC frigate equiped with similar armaments, could hit a Covenant ship at such ranges)

Weaknesses: Sacrifices speed & manoeuverability in favour of durability. A well placed hit to certain sections, such as the main engines or engineering, can cripple or even outright destroy the ship. A "Smart" AI is needed to make optimal use of armaments as human gunners cannot make the required calculations or adjustments quick enough.


  • Point-defence guns: This ship class boasts of a decent, though still inadequate, array of point-defence guns all along the hull. These 50 mm twin MAC cannons can fire high explosive projectiles at high velocities with a sinlge well placed burst being capable of downing the energy shields of a Type-31 Seraph exoatmospheric fighter. However, human gunners are incapable of making optimal use of them to take down incoming enemy fighters and boarding craft or missiles and can thus waste a lot of precious shots. A "Smart" AI is needed to make the required calculations in real time and fire these guns with great accuracy.
  • Archer missiles: A ship-to-ship missile used by the UNSC navy. A large number of these missiles hitting the superstructure of an unshielded ship could potentially cripple it while a single one could easily cripple most smaller craft such as exoatmospheric fighters or boarding craft. However, even ninety Archer missiles can't down the energy shields of even smaller Covenant warships. Although not very powerful on their own, these missiles can make up for it with sheer number. This ship class is usually equipped with dozens of missile pods with each pod containing 24 or 26 missiles. These ships could thus carry hundreds of Archer missiles or even a few thousand. The heavily modified Pillar of Autumn boasted of 300 pods of 26 missiles and thus a total of 7,800 Archer missiles.
  • Magnetic Accelerator Cannon: The main MAC gun of these ships is of such proportions that the entire external superstructure had to be built around them. It is capable of firing 600 tonne ultra-dense projectiles (made of tungsten or tungsten carbide with a depleted uranium core) at velocities of up to 30 km/s on the highest power setting. The main MAC is usually fired at a much lower setting - sacrificing sheer kinetic energy for higher recharge and fire rates. Even at these lower settings however, the fired projectile still can still retain enough kinetic energy to down the shields of smaller Covenant cruisers in a few hits. A well placed direct hit at full power to the hull of unshielded ships as big as or smaller than a Covenant CCS-class cruiser can often be crippling.
  • Shiva-class nuclear missile: A versatile missile which can be fit with nuclear warheads of various yields. As seen during the Battle of Chi Ceti, it is capable of hitting targets out to at least 3,000 km. Shiva-class missiles carried by ships such as these are usually fitted with the 30 Megaton HAVOK tactical nuclear warhead.

Note: The Halcyon-class is powered by fusion reactors which provide power via the fusion of deuterium, an isotope of hydrogen. The reactors can be set to self-destruct via a command from an AI or via manual setting with authorization from the ship's captain. They can also be made to violently fail and explode by destabilizing the power boosting magnetic shields around the reactor cores. When the reactors blow, the explosion can produce temperatures far exceeding that of the cores of main sequence stars and the explosion can be powerful enough to cause great devastation. When the Pillar of Autumn self-destructed during the Battle of Installation 04, the explosion devastated the main superstructure of the 10,000 km diameter ring-world which broke up into numerous fragments. The event left behind a crater spanning roughly two thirds of the 318 km width of the ring and multiple kilometres deep. The crater it left behind was as large as, if not larger than, the one carved out by the asteroid which caused the Cretaceous-Paleogene extinction event - an impact with release of energy of over 420 Zettajoules.


Notable Victories:

Notable Losses:

Inconclusive Matches: