UNSC Pillar of Autumn

The UNSC Pillar of Autumn (UNSC Cruiser C709)  was a. Informally, she was simply referred to as "The Autumn", and informally abbreviated as the "PoA".

History
Early on in the Human-Covenant War, it participated in the Battle of Arcadia in February 2531. The Autumn along with three other ships managed to fire on a Covenant ship that was still recharging it's shields, most likely destroying it. Though heavily damaged, it delivered experimental Rhinos to the surface to penetrate Covenant shield defenses.

Mothballed and due to be scrapped like the remainder of the Halcyon-class cruisers (said to be the toughest of all cruisers despite their poor speed and firepower), the Autumn was brought back into active duty during the Human-Covenant War. She had undergone a refit in 2550 to serve, interestingly enough, in the Zeta Doradus System. Under the command of Captain Jacob Keyes, she was to serve as an inconspicuous launch pad, for a covert offensive involving locating the Covenant homeworld and capture of Covenant leadership, the Prophets by SPARTAN-II Super soldiers and received a refit to prepare her for the upcoming mission. The refit rectified a number of deficiencies in the original design and made her a competitive re-addition to the sorely pressed UNSC Navy. At the time of her destruction in 2552 she was 43 years old. The Pillar of Autumn was ultimately unable to embark on the aforementioned operation due to the UNSC defeat at the Battle of Reach and was one of the few ships to escape the disaster, albeit with moderate damage and the loss of a third of its tech staff. Although the Cole Protocol demanded a random Slipstream jump, the AI Cortana, without the knowledge of the crew, purposely guided the ship to the planet Threshold based on map coordinates extracted from a Forerunner artifact on Sigma Octanus IV. The result was the discovery of Installation 04, or "Halo".



However, a large fleet of Covenant cruisers were located on the other side of the planet. They had followed the PoA through Slipspace from Reach and arrived at the Autumn's co-ordinates earlier due to their more advanced understanding of Slipstream Space. A brief and uneven battle against a Covenant battle group of a dozen superior s then occurred in near-Threshold space. The orbital battle resulted in critical damage being inflicted upon the Pillar of Autumn. Enemy boarding parties disabled the MAC's fire control with a demolition charge, but not before she made a good account of herself by destroying four enemy warships and damaging several others. The Pillar of Autumn's survival against superior forces was due in part to a Prophet's directive to disable, rather than destroy her, out of fear that her destruction might damage Halo, which had religious significance to the Covenant. Before setting an "emergency-landing," the Autumn released its cryo tubes into space, one of them containing SPARTAN-058, Linda. The ship was then crash landed onto Halo by one of Cortana's subroutines. The vessel, damaged beyond repair, tore a deep gash in the ground for several hundred meters, bounced, then came to rest upright and balanced over a cliff on a barren peninsula.

Prior to the crash, much of her crew had taken to the escape pods, including Cortana who was being carried within the Master Chief's suit. Others were evacuated by Pelican dropship or even in drop pods, as was the case for a complement of ODSTs. Despite the confusion most of the crew survived, to reach Halo and engage Covenant ground forces.

Later, the surviving Pelicans were employed to retrieve munitions from the crashed ship to sustain this effort. The human forces successfully neutralized the Covenant vehicles and some of the infantry stationed at the crash site and retrieved weaponry and vehicles to use in their guerrilla war against the Covenant.

Despite the abuse sustained during the space battle and the following crash the Pillar of Autumn remained intact, and was subsequently occupied by investigating Covenant forces and later by Flood. The threat posed by the latter was deemed sufficiently great for ODST Major Silva to give SPARTAN-117 and Cortana the order to detonate the ship's still-functioning fusion power cores in a bid to destroy Halo, thus preventing the Flood from escaping.

Having manually triggered the destabilization of the power cores after subsequently destroying the casings on the cores, an intervention by the AI 343 Guilty Spark halted the remote detonation, SPARTAN-117 and Cortana commandeered a Longsword from one of the Pillar of Autumn's docking bays and achieved a safe minimum distance before the ship exploded, causing the ring-world to fall apart. According to Doctor Halsey its memory would live on for years to come.

Power Plant
The Pillar of Autumn was refitted with an improved nuclear fusion engine that featured two smaller reactors around a larger one, which were capable of boosting the overall power output by 300% if needed, this proved useful while running from the Covenant at Reach and Installation 04.

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 is 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. Also, the Autumn's Engine cores could be easily overloaded and the explosion generated could destroy an entire Halo Ring and vaporize a great part of a Covenant Fleet.

Armament
The upgraded Pillar of Autumn received extensive refits, including several to its weapons systems. Eventually, it was host to a very powerful armament; far in excess of the original Halcyon-class ships. It is quite curious that this ship would be given so many powerful weapons. A nuke inside of a ship's shielding would effectively destroy it. While effective for destroying a Covenant ship, the mission the Pillar of Autumn was designed for was to help the SPARTAN-IIs "disable" a Covenant ship to be commandeered, not destroyed. However, since the Autumn was going on the mission alone, it needed plenty of firepower.
 * One MAC Cannon which was capable of firing three consecutive shots on one charge, each round weighing 600 tons. The "Pillar of Autumn's" MAC gun fires lighter projectiles compared to most ship grade MACs, but extra power capacitors and power recycling systems allow it to fire more rounds per charge.
 * 300 Archer Missile Pods which were arranged in thirty columns and ten rows. Each pod contained 26 individual devices, equaling 7800 missiles.
 * Four Shiva Nuclear Warheads, one of which is loaded on a remote-controlled Longsword interceptor.
 * Forty 50mm MLA Auto-cannons with overlapping fields of fire for point defense against single ships. These cannons were later scavenged by the surviving humans on Installation 04 for Alpha Base.

Engine Room
The Pillar of Autumn's engine room, or just "Engineering", was a large, three-deck high chamber allowing access to the fusion engine core. Side passages allowed for movement from the bottom deck all the way up to the catwalks on the third. The manifolds into the cores were suspended above the second deck. Controls on the third retracted these manifolds, exposing a vent that led directly into the core. It was using this method to expose the core via the vents that the Master Chief ultimately destroyed the ship and "Halo". This room is the largest room in the Pillar of Autumn with the exception of the hanger bay and the "Leap of Faith" room.

Airlocks

 * Airlock 31: The Lifeboat of this airlock was destroyed by the Covenant to make way for a Boarding Craft.
 * Airlock 32: The Lifeboat of this airlock was destroyed by the Covenant to make way for a Boarding Craft.
 * Airlock 51: The Lifeboat of this airlock managed to make it out of the vessel, but was destroyed by unseen Covenant artillery.
 * Airlock 52: The Lifeboat of this airlock managed to make it out of the vessel.
 * Airlock 53: The Lifeboat of this airlock managed to make it out of the vessel.
 * Airlock 61: The Lifeboat of this airlock managed to make it out of the vessel with the Master Chief, Cortana, 9 other Marines on board and the Bumblebee pilot.
 * Airlock 62: The Lifeboat of this airlock managed to make it out of the vessel.
 * Airlock 63: The Lifeboat of this airlock managed to make it out of the vessel.

Pillar of Autumn Command Crew

 * Captain Jacob Keyes -- Ship Captain
 * Cortana -- Temporary ship AI
 * Unknown Backup AI, theorized by some to be Wellsley though this is probably false due to the fact that Wellsley was a dumb AI. Also could be Solipsil
 * Lieutenant Dominique -- Communications Officer
 * Lieutenant Aki Hikowa -- Weapons Officer
 * Lieutenant Hall -- Operations Officer
 * Ensign William Michael Lovell -- Navigation Officer
 * Lieutenant Commander Gail Purdy -- Chief Engineer
 * Crewman Abiad
 * Crewman Wang
 * Crewman Singh
 * Ensign Ellen Dowski

Other Naval Personnel

 * Master Chief Petty Officer SPARTAN-II John-117
 * Tech Chief Thom Shephard -- Cryogenics Technician
 * Tech Officer First Class Mary Murphy -- Air Traffic Technician
 * Tech Officer Sam Marcus -- Cryogenics Technician
 * Petty Officer Third Class Pauley -- Radio Technician
 * Petty Officer Third Class Cho -- Radio Technician
 * Flight Officer Captain Carol "Foehammer" Rawley -- Pelican Pilot-Echo 419
 * Lieutenant "Cookie" Peterson -- Pelican Pilot
 * Lieutenant Rick Hale -- Pelican Pilot
 * Flight Officer Mitchell -- Pelican Pilot
 * Warrant Officer Sheila Polaski -- Pelican Pilot
 * Lieutenant Frye -- Pelican Co-Pilot
 * Crew Chief Cullen -- Pelican Communications Officer
 * Lieutenant Elias Haverson
 * Petty Officer Second Class Linda-058 (Unconscious in Cryo Tube)

Individuals

 * Major Antonio Silva
 * First Lieutenant Melissa McKay
 * Second Lieutenant Dalu
 * Second Lieutenant Oros
 * Staff Sergeant Marvin Mobuto
 * Master Sergeant Lister
 * Company First Sergeant Tink Carter
 * Sergeant Corly
 * Staff Sergeant Avery Junior Johnson
 * Sergeant Parker
 * Staff Sergeant Pete Stacker
 * Gunnery Sergeant Waller
 * Private First Class M. Fitzgerald
 * Private Bisenti
 * Private First Class Hosky
 * Private First Class Wallace A. Jenkins
 * Corporal Locklear
 * Corporal Lovik
 * Corporal Wilkins
 * Lance Corporal "Snaky" Jones
 * Corpsman "Doc" Valdez
 * Private Kappus
 * Private Chips Dubbo
 * Private Manuel Mendoza
 * Private O'Brien
 * Private Marie Postly
 * Private Riley
 * Private Satha
 * Al-Thani
 * Dawkins
 * Suzuki
 * Unnamed Corporal

Units

 * 830 Marines-1 ODST Battalion, 1 Marine Battalion
 * Combat Team Alpha
 * Combat Team November
 * Combat Team Sierra
 * Combat Team Victor
 * Fire Team Charlie
 * Fire Team Zulu
 * Fifth Platoon
 * Fourteenth Platoon
 * Twenty-Second Tactical

Others

 * Jonesy (Unknown crew member's cat)

Trivia

 * The Pillar of Autumn is approximately 1.17 km long. This, however, contradicts the final level of Halo: Combat Evolved where the player must drive along a 3 km long service corridor that supposedly runs the length of the ship. This was probably for generating the tension and atmosphere necessary for the level. It is also possible that due to the many twists and turns, the service corridor is stretched along several levels of the ship, making it possible for it to be that long. This is also the Master Chief's serial number.
 * The Marathon logo is prominently displayed on the Pillar of Autumn's starboard and port sides. The ship's official emblem has the Marathon logo as well. The marathon logo was also visible in the window of the ship in the opening cutscene of the level The Maw.
 * Master Chief escaped with the airlock number 61,6+1=7, another 7 reference.
 * The bulletin board just outside the bridge of the ship contains a number of amusing clips, some throwbacks to Marathon. These can be examined on the first level of Halo: Combat Evolved. The board has a flier for a missing cat called Jonesy. This is a reference to the Alien movies, where the cat's name was Jonesy.
 * In Halo: Fall of Reach, Dr. Halsey asked which ship Cortana chose for the original mission to capture a Covenant Prophet. Cortana chose the Pillar of Autumn for the skeletal structure, designed by Dr. Robert McLees. "...At the time, deemed unnecessarily over massed and costly due to series of cross-bracing and interstitial honeycombs... Halcyon-class ships, however, have a reputation for being virtually indestructible. Reports indicate these ships being operational even after sustaining breaches to all compartments and losing ninety percent of their armor." This, obviously, implies that the Pillar of Autumn can take an immense beating, therefore being a good choice on Cortana's part.
 * The Pillar of Autumn mess-hall offered a choice between turkey, hamburgers, cheeseburgers, hot dogs, meatloaf, and a dish named Chef's Special. Beverages included cola, water, lemon/lime, lemonade, root beer, coffee, orange juice, hot tea, hot chocolate, iced tea, and Chef's Surprise.
 * While The Fall of Reach mentioned the Autumn having a command chair, in Halo: Combat Evolved, such a chair is not seen.
 * In cutscenes, the Pillar of Autumn never moves, it is just a piece of BSP geometry. However, the cameras and the background moved in such a way that it gave the illusion of movement.
 * For a ship of its size, the Autumn ' s bridge is strangely undersized, and is placed in a tactically poor position.
 * Although the auto-cannons were removed in Halo: The Flood, they are still visible in cutscenes set after the human raid.
 * The Pillar of Autumn bears a striking resemblance to the USS Sulaco, the main spaceship from the movie, Aliens.
 * On the Level "Pillar Of Autumn", when you walk past Master Chief's Cryo Chamber, if you walk past it a little bit and turn around, you can walk into the room where Linda-058 was monitored, its control room would be next to that run by Samuel N. Marcus
 * The Pillar of Autumn makes a cameo in Halo Wars, providing Rhinos for the player on Arcadia.
 * The Pillar of Autumn has a sister ship known as the UNSC Dawn Under Heaven.
 * The Pillar of Autumn strongly resembles the Bothan Assault Cruiser from Star Wars
 * On the bulletin board in the Pillar of Autumn Marines are told to "keep it clean", the slogan for the next Halo related game, Halo: ODST.
 * In Halo Wars, the Pillar of Autumn was said to have supplied the ground forces of the Spirit of Fire with Rhinos on Arcadia (Planet) from the Autumns inventory. Thus, explaining there weren't any references to the Rhino tanks in Halo: Combat Evolved or Halo: The Flood in terms of actual canon leaving some fans to believe that the Autumn left all of her Rhinos at the Spirit of Fire's disposal.