2513

January

 * January: The United Rebel Front retakes Eridanus II.

June

 * June 19: Dr. Catherine Halsey decides upon the final name of the SPARTAN-II program, up until then tentatively referred to as "ORION Project Generation Two".

Unknown

 * Initiation of Operation: TREBUCHET.
 * Brain mutations are specifically outlawed by the UNSC MED CORPS.
 * Colonel Ponder leads a force into Elysium City to retrieve an 'Innie'. A confrontation develops and due to an overeager sniper, a grenade is detonated causing Ponder to lose his arm and be demoted.
 * Latest possible release of Pelican and Warthog series to the UNSC.
 * Alexander becomes the sixth captain of the UNSC Spirit of Fire