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January

 * January 10: Draco III is invaded by the Covenant and its civilian population is massacred.

February

 * Early February: Edward Buck requests a transfer for the Orbital Drop Shock Troopers in response to the loss of his homeworld, Draco III.
 * February 27: Edward Buck is transferred to the ODSTs by UNSC High Command.

May

 * May: After a long drawn out battle, the Battle of Actium ends in a UNSC defeat and Actium is glassed.
 * May 10: During the Battle of Actium, Colonel Akono Menteith delivers a stirring speech, rallying the men and women of the 53rd Armored Division to perform great feats of heroism.
 * May 30: A conversation takes place between Franklin Mendez and Kurt-051, regarding the reassignment of some members of SPARTAN-III Beta Company, including SPARTAN-B312 and Kat-B320, to non-combat roles.

July

 * July 3: Operation: TORPEDO commences. Spartan-IIIs of Beta Company launch an assault against a Covenant refinery on Pegasi Delta. 298 of the 300 SPARTAN-IIIs are killed during the assault, with Tom-B292 and Lucy-B091 as the only survivors.

September

 * September: Edward Buck takes shore leave on Castellaneta in orbit over Saturn, where he meets ONI operative Veronica Dare for the first time.
 * September 16: Class-II Spartan-IIs undergo augmentations. Yasmine Zaman has her fourteenth birthday.
 * At some point during her augmentations, Yasmine Zaman dies from complications. Her brain is later donated for the creation of the AI known as "Melissa".

Unknown

 * Richard Lash transfers to the Prowler Corps.
 * Natalie Aiken is born on Vodin. Her mother dies during childbirth, leaving her father, Randall Aiken, to raise her.
 * Mason Hundley's father dies in the Procellarum basin on Luna, where his skiff ran into severe winds during a retrieval maneuver.