Pillar of Autumn
From Halopedia, the Halo wiki
Summary
The Pillar of Autumn is a heavily modified United Nations Space Command Halcyon-class cruiser in Halo: Combat Evolved, often referred to as the "POA" for short.
The Pillar of Autumn was one of few ships which escaped The Battle of Reach. The ship made a slipstream jump to the planet Threshold, location of Forerunner Installation 04, which the Covenant believed was their religious icon "Halo." The remaining crew believed the jump to be random, in order to avoid leading the Covenant to Earth as per the Cole Protocol; in actuality the AI Cortana interpreted symbols on a Forerunner artifact into map coordinates.
Modifications to the Pillar of Autumn include reinforced armor, increased missile capacity, an improved Shaw-Fujikawa engine, and a Magnetic Accelerator Cannon capable of firing three "shredder shots" on a single charge.
The Pillar of Autumn is a relatively small ship for its class, but the reinforced hull and armor place it in a higher tonnage range in the UNSC fleet.
Before the modifications to the vessel, the ship was was due to be scrapped–the Halcyon-class was widely regarded as a joke by UNSC officers and crewmen. The refitted Pillar of Autumn, however, was one of the most powerful ships available to the UNSC.
After the POA crash-landed on "Halo" it is unsure what happened, but during the end of the events on the ring the Covenant, Flood and the Master Chief raced to the crash site to try and escape from the ring-world.
The Pillar of Autumn suffered severe damage from Covenant forces orbiting Threshold and crashed on "Halo". Cortana and the Master Chief manually detonated the ship's nuclear fusion engines in order to destroy "Halo" and prevent Flood and Covenant forces from escaping.
The Pillar of Autumn is currently presumed destroyed along with most of the crew (including Captain Jacob Keyes, Commanding Officer of the POA).
Images
File:PoA crash.jpg File:PoA crash2.jpg 
