Editing UNSC Pillar of Autumn

|commisioned          =

|fate                = Self-destructed on September 22, 2552 to destroy [[Alpha Halo]]

|ai                  =  

*[[Cortana]]

*[[Wellsley]]

|mass            =*'''Pre-[[2552]] refit''': 11 million tonnes{{Ref/Reuse|Enc22}}

*'''Post-2552 refit''': 9 million metric tons{{Ref/Reuse|Warfleet}}

|power          =*'''Pre-2552 refit''': 3 [[Fusion drive#Mark II Hanley-Messer DFR|Mark II Hanley-Messer DFR]]s<ref name= "data drop"/>

*'''Post-2552 refit''': Experimental reactor set {{C|1 primary, 2 secondary}}{{Ref/Reuse|FoRC29}}{{Ref/Note|On page 274 of ''Halo: The Fall of Reach'', it is stated that ''Pillar of Autumn''<nowiki>'</nowiki>s refit power plant consists of a single main reactor linked to two secondary ones; this arrangement is referenced again later on when Cortana gives a damage assessment of the ship to Captain Keyes. However, in ''Halo: Combat Evolved'', it is implied that each of the four exhaust manifolds is linked to an individual fusion reactor, each of which is destroyed by John-117 in the [[The Maw|final level]]. This page follows the information given in ''Halo: The Fall of Reach'', as the novel describes the reactor system in more detail.}}

|maneuver drive  =*'''Pre-2552 refit''': 3 Mark II Hanley-Messer DFR<ref name= "data drop"/>

**8 [[R7 thrust coupling]]s

**[[Emergency thruster]]<ref name="FoRC33">'''Halo: The Fall of Reach''', ''Chapter 33''</ref>

|crew            = *1,000 Naval personnel{{Ref/Reuse|Warfleet}}

*9+ [[M145D Rhino]]s <small>(previously)</small>

|hull            = [[Titanium-A armor|Titanium-A battleplate]]{{Ref/Reuse|Warfleet}}

|armaments      =

*1 [[Magnetic Accelerator Cannon#Specialized and modified versions|Mark II, Light Coil - 56A2D4/MAC]]<ref name="waypointarticle">[https://www.halowaypoint.com/en-us/universe/vehicles/pillar-of-autumn '''Halo Waypoint''': ''Pillar of Autumn'']</ref>

*4 [[Shiva-class nuclear missile]]s mounting [[HAVOK tactical nuclear weapon|HAVOK warhead]]s<ref name="FoRC29">'''Halo: The Fall of Reach''', Chapter 29</ref>

*32 M58 Archer missile pods{{Ref/Reuse|Warfleet}}

*18 M910 Rampart point defense guns<ref name= "Warfleet" />

*6 [[M66 Sentry autocannon]]s{{Ref/Reuse|Warfleet}}

*At least 18 [[Class-3 Bumblebee]]s

*216 [[drop pod]]s ([[M8823 drop pod|M8823 HEV]]{{Ref/Reuse|Warfleet}} and [[M8900 drop pod|M8900 SOEIV]]){{Ref/Level|HFR|Rubble}}

*[[UH-144 Falcon]]s<ref name="FTR"/>

|air facilities  =

The cruiser was decommissioned with the remaining {{class|Halcyon|light cruiser}}s, but was reactivated as the war worsened. ''Pillar of Autumn'' was pulled from long-term storage and was refitted in [[2550]] to serve as an emergency support ship in a conflict near [[Zeta Doradus]].{{Ref/Reuse|HCESGuide}}{{Ref/Reuse|FoRC25}}

By [[2552]], it was obvious to the UNSC that the war could not be ended with conventional military action. A desperate plan, known as [[Operation: RED FLAG]] was conceived to end the war by capturing Covenant leaders and forcing the enemy to the negotiating table. [[Reach|A colony world]] would be sacrificed to the Covenant to allow SPARTAN-II commandos to board and disable a Covenant ship, locate the Covenant [[High Charity|homeworld]], and abduct the targets. ''Pillar of Autumn'' was selected on August 25 by the AI Cortana to disable an enemy ship and deliver the Spartans aboard; the ship was selected for the ''Halcyon''-class's durability, despite its class's usual lack-luster offensive capabilities.{{Ref/Reuse|FoRC25}} Command of the ship was given to [[Jacob Keyes|Captain Jacob Keyes]].

The cruiser received another refit designed by Senior Engineer Adam Crokett{{Ref/Reuse|Warfleet}} for the new mission, including a state-of-the-art fusion power plant and improved weaponry.{{Ref/Reuse|FoRC25}} Furthermore, the command bridge was upgraded with a Tier III datacore to house Cortana and the drop pod bays were significantly expanded.{{Ref/Reuse|Warfleet}} After the refit, Cortana was transferred to handle the shakedown.

''Pillar of Autumn'' was roughly 43 years old at the time of its escape from Reach and later destruction on Installation 04. It was a cruiser of the ''Halcyon''-class, the lightest cruisers in the UNSC Fleet.<ref name="FoRC25">'''Halo: The Fall of Reach''', Chapter 25</ref>

The ''Pillar of Autumn'' was one of only eleven ''Halcyon''-class cruisers to be built with a unique internal frame that was designed by [[Robert McLees (ship designer)|Doctor Robert McLees]]. Incorporating a series of interstitial honeycombs and cross-bracings, it was deemed unnecessarily over-massed and costly due to a series of cross-bracings and interstitial{{Ref/Reuse|FoRC25}} [[Titanium-A armor]] honeycombs.{{Ref/Reuse|FoRC29}} This led to the design being dropped from future models of ''Halcyon''-class ships,{{Ref/Reuse|FoRC25}} and quickly led to most of these ships being removed from service.{{Ref/Reuse|data drop}} However, this unusual framing scheme allowed the ship to function even after sustaining critical levels of damage.{{Ref/Reuse|HCESGuide}} This offset its usage of older, heavier armor patterns,{{Ref/Reuse|Enc22}} which provided inferior protection than what was considered standard in 2552.{{Ref/Reuse|FoRC25}}

These protective qualities were improved as part of the ''Autumn''<nowiki>'s</nowiki> refit in 2552. The hull was upgraded to the latest Titanium-A ablative armor plating, which resulted in great savings in terms of volume and mass.{{Ref/Reuse|Enc22}} Hydraulic reinforcements activated during emergencies complemented the existing toughness of its frame.{{Ref/Reuse|FoRC29}} The refit substantially expanded both the [[SOEIV]] launch bays and hangar capacity, with the latter made possible by sacrificing long-term accommodations. It also received an Omega-pattern bridge with a Tier-III datacore.{{Ref/Book|Enc22|Id=Enc22|Chapter=Human Ships, Cruisers|Page=119}} Protruding from its front face is a foremast that is equipped with [[slipspace]] navigation sensors and hardened [[UNSC battle network|battlenet]] transponders. A planetary scanning array is mounted just below its bridge, which is outfitted with planetary survey sensors and probe/satellite launchers. Four compact auxiliary fusion rockets are installed on either side of the cruiser, and while they are capable of a high-thrust, they are considered inefficient in their design. At the very top of the engine cowling is a multipurpose scan array, which contains tactical sensors and an electronic eavesdropping suite.{{Ref/Reuse|Warfleet}}.

Prior to being refit for the Spartan mission, ''Pillar of Autumn'' was equipped with three Mark II Hanley-Messer deuterium [[Fusion drive|fusion engines]], which supplied only 10% the power of the standard [[2552]] UNSC Navy reactor. ''Pillar of Autumn'' was refitted with a set of improved nuclear fusion engines that featured two smaller reactors around a larger one, which were capable of boosting the overall power output by 300% for a short time if needed.{{Ref/Reuse|FoRC29}}

Fusion reactors generate extreme heat which must be removed in order for them to remain active without overheating. The Autumn's overhauled reactors were an especially severe case of this. Usually, the excess heat was conducted to a chemical agent which would then vent into space. However, the ''Autumn''{{'}}s upgraded specifications also included an upgraded cooling system, which featured a "laser-induced optical slurry of ions chilled to near-absolute zero", which was far more efficient than the typical method and removed the reliance on expendable chemical temperature-control substances. In essence, the amount of excess heat removed by the new system increased as the reactors' output did. This self-regulating and self-cooling power plant was critical in combat since it virtually eliminated a commander's concerns about overheating and slagging a ship's engines.{{Ref/Reuse|FoRC29}}

''Pillar of Autumn's'' reactors were able to be [[Fusion drive#Use as improvised weapons|overloaded by explosives]], either grenades or rockets, destroying the vulnerable vent cores. Once these were destroyed, the reactors began to go critical, resulting in temperatures of over one hundred million degrees and a thermonuclear explosion large enough to tear apart a Halo installation.<ref>'''[[Halo: Combat Evolved]]''', campaign level ''[[The Maw (Level)|The Maw]]''</ref> This explosion was later revealed to be similar in nature to a [[supernova]] and resulted in the creation of [[Element 120.V|a new element]] on [[Alpha Shard|a surviving shard]] of the installation.{{Ref/Reuse|Nightfall}}

In 2550, the ''Pillar of Autumn'' was reactivated in order to support operations near the Zeta Doradus system. As part of this refit, which had also been applied to other ''Halcyon''-class cruisers, it received one MAC and six additional [[Archer missile#M58 Archer|M58 Archer missile]] pods,{{Ref/Reuse|FoRC25}} bringing its total missile arsenal to 10 pods. Each of these pods carried a total of 24 missiles. For anti-aircraft and anti-missile protection, it retained its existing 40 [[M910 Rampart point defense network|M910 Rampart point defense gun]]s.<ref name= "data drop"/>

A subsequent refit was given to the ''Pillar of Autumn'' to prepare it for its role in Operation: RED FLAG in 2552. As part of this, its arsenal was drastically expanded, resulting in a final armament of:

*One [[Magnetic Accelerator Cannon|Mark II, Light Coil - 56A2D4/MAC gun]]{{Ref/Reuse|waypointarticle}} that ran two-thirds the length of the cruiser{{Ref/Reuse|Warfleet}} fired lighter projectiles compared to most ship grade MACs, but these rounds worked much like [[shredder round]]s. Each charge was able to fire 3 rounds,{{Ref/Reuse|FoRC29}} thanks to the addition of prototype power capacitors and rapid-cycling MAC coils.{{Ref/Reuse|Enc22}}

*Thirty-two M58 Archer missile pods.{{Ref/Reuse|Warfleet}}

*Four [[Shiva-class nuclear missile]]s, equipped with thirty-megaton HAVOK warheads. One was loaded onto a remote-controlled Longsword interceptor, while the other three were ship-launched.<ref>'''Halo: The Fall of Reach''', Chapter 29, page 275 (''"In response to [[Captain Keyes]]' question about the small single ships in the launch bay, [[Lieutenant]] [[Aki Hikowa|Hikowa]] states, "Yes Sir. One of the Longswords is equipped with a [[Shiva-class nuclear missile]]; it can be remote piloted. We also have three HAVOC Warheads on board"'').</ref>

*Eighteen M910 point defense guns with overlapping fields of fire for point defense against single ships. These benefitted from a new software updated added as part of the refit.{{Ref/Reuse|Enc22}} Few of the guns were mounted on the bottom-fore section, as transient magnetic bursts from the MAC tended to magnetize the guns.{{Ref/Reuse|FoRC29}} Two of these cannons were later salvaged by the surviving UNSC personnel for [[Alpha Base (Installation 04)|Alpha Base]].{{Ref/Reuse|Warfleet}}

*Eight [[Spitfire naval coilgun battery#Mark 33 Spitfire|Mark 33 Spitfire naval coilgun batteries]].{{Ref/Reuse|Warfleet}}

*Six [[M66 Sentry autocannon]] turrets.{{Ref/Reuse|Warfleet}}

*[[Fireteam Raven]]<ref name="FTR">''[[Halo: Fireteam Raven]]''</ref>

*In ''[[Halo: The Fall of Reach]]'', the description of ''Pillar of Autumn'' is considerably different from its ''Halo: Combat Evolved'' incarnation. The bridge is described as having a command chair and a curved viewport; in ''Halo: Combat Evolved'', this chair is absent and the window consists of several flat sections. The novel also describes the bridge as being extremely cramped, with only a meter of space between the command chair and the other stations,<ref name="for277">'''Halo: The Fall of Reach''', ''page 277''</ref> while in the game, the bridge is clearly more spacious. According to the novel, there is also an elevator leading directly from the engine room to the bridge.{{Ref/Reuse|for277}} In the game, the engineering and the bridge are on the same level, and there are no doors which may belong to an elevator adjoining the bridge. In addition, the engine room is described as being "hexagonal", while in the game,{{Ref/Reuse|FoRC29}} it consists of two vaguely rectangular chambers with the engine core in the middle. The ship is also described as having rotating centrifuges to generate [[artificial gravity]];{{Ref/Reuse|FoRC29}} no rotating sections are present in the game, unless they are located within the hull.

File:HFR PrepareToDrop.jpg|The SOEIV bay on the ''Autumn''.

File:HTVS2 PillarOfAutumn Render.png|A render of the ''Pillar of Autumn'' asset created for ''[[Halo: The Television Series Season Two]]''.