2531

February

 * The final battle of the Harvest Campaign is won in space: Preston Cole's fleet engages the alien warships that have again returned to the Harvest colony. Six years after the planet was attacked, UNSC forces emerged victorious at great cost.
 * The UNSC Spirit of Fire enters the Epsilon Indi system and arrives back at a glassed and partially frozen Harvest, encountering the remnant of Covenant troops led by an Arbiter that are in the process of uncovering a Forerunner Relic on the planet.
 * February 4th: Captain James Cutter of the UNSC Spirit of Fire makes an entry in his log, reflecting on the five years leading up to this point in the war against the Covenant.
 * Serina instructs that production of M41 LAAG weaponry cease on Harvest, Warthogs instead to be upgraded with the M68 Gauss Cannon. Not that it makes much difference as drivers continue to 'splatter' their Covenant enemies, much to the frustration of their maintenance teams.
 * Helena Roman is KIA against the Covenant. Captain Cutter sends a message to her family in regards to her death.
 * Anders receives some unexpected readings on an EM band and asks a Hornet squadron en route to Rally Point Baker to investigate. They end up sighting a battalion of Sangheili. Sergeant Forge is assigned to Quadrant 4 to investigate.
 * February 9th: Spirit of Fire arrives at the planet of Arcadia during battle, where they meet SPARTAN Red Team.
 * February 23rd: Battle of Shield 0459. Medical officers aboard the Spirit of Fire mistake the Flood for a virus.
 * February 25th: Spirit of Fire escapes Shield 0459 thanks to the sacrifice of John Forge

May

 * May 1st: Raid on Camp New Hope. Spartan-II Blue Team infiltrates Camp New Hope, on planet Victoria, in the 111 Tauri System. General Howard Graves of the Insurrectionists is killed and three FENRIS Nuclear Warheads are recovered.

June

 * June 12th: Feeling she cannot provide her daughter the care she deserves, Dr. Catherine Halsey sends Miranda to live with her father, Lieutenant Jacob Keyes.

October

 * October 24th: Colonel James Ackerson proposes the SPARTAN-III Program to leading members of Office of Naval Intelligence.

November

 * November 7th: Spartans Kurt-051, Kelly-087 and Fred-104 are dispatched to investigate Construction Platform 966A for suspected Rebel activity. Kurt-051 experiences a thruster pack malfunction and is sent into interplanetary space. The Prowler UNSC Circumference and the Frigate UNSC Tannenberg start immediate rescue operations, however, after over 5 hours of searching, nearby Covenant activity forces the search to be terminated, and Kurt-051 is 'officially' declared MIA. In actuality the operation was a ruse: Kurt is picked up by Colonel James Ackerson and recruited to train his SPARTAN-IIIs.

December

 * December 19th: Nicole-458 is born.
 * December 27th: 497 recruits arrive at Camp Currahee on Onyx beginning the Spartan III program under the command of Spartan-051 forming what will later become Alpha Company.

Other events

 * Rear Admiral Cole is promoted to admiral upon his return to Earth and learns that a number of outlying colonies have been destroyed, leaving behind no survivors. He begins to move his fleet around, trying to intercept the invaders. Ground and ship-to-ship battles begin in earnest, raging throughout the Outer Colonies.
 * The Type-33 Light Anti-Armor Weapon is first encountered by UNSC forces.
 * Spartan-II Blue Team disrupts Insurrectionist activity in Micronesia and breaks up a saboteur ring on Reach between November 2530 and May of this year.
 * The MJOLNIR Powered Assault Armor/EOD variant enters service.
 * The Assembly takes note of a "third participant" mentioned in the Covenant Battle Network during the battle for the Shield World, one which caused "irrational terror" for the Covenant. While presenting the possibility of contacting this third faction, they decide not to, due to the risks involved.
 * In January or February, Spartan Daisy-023 and former Spartan Ralph-303 are killed during the Harvest Campaign.