From Halopedia, the Halo wiki
2550 was a year in the 2550s in the 26th century.
- The Banished raid the UNSC's Carter Guard Armory, with Atriox personally killing a group of Orbital Drop Shock Troopers defending it with his bare hands. Helmet cam footage from Sergeant B. Wright, an ODST killed in the raid, provides the Office of Naval Intelligence with its first look at Atriox, who is identified to agents by a captured Banished Unggoy.
- Dr. Catherine Halsey determines that Cortana, by disabling the viral termination code in her matrix, may be able to overcome the AI's typical seven-year life cycle.
- ONI agents 'D' and 'S' review the helmet cam footage from Sergeant B. Wright, an ODST killed in the raid on the Carter Guard Armory six weeks prior.
- Miranda Keyes is awarded the Silver Star and promoted from Lieutenant to Lieutenant Commander in a ceremony in downtown Quezon on Reach.
- Intersystem News released their report of the event. Dr. Halsey also wrote down in her journal how she felt about Miranda's career up until that point and about the ceremony.
- Professor Laszlo Sorvad starts his archaeological survey of a meteorite debris field near Visegrád, Reach.
- Seven Covenant-held locations have been raided by the Banished by this time, the most recent of which was a forward outpost meant to be attacked as part of Operation: SLOW DIVE.
- At some point after July 9, Minab is glassed by the Covenant.
- Lieutenant Wagner suffers severe plasma burns to a third of his body.
- A meteorite impact crater was discovered near Visegrád. ONI noted the significance of the site and had many researchers analyzing it. However, no forced relocation of nearby residents was enacted.
- The Battle of Gamma Pavonis VII occurs.
- The Battle of Ballast occurs. Ballast ultimately escapes being glassed.
- Blue Team is deployed to the ice moon Umagena to capture Insurrectionist Hector Nyeto. However he isn't actually there.
- Halo Wars 2, Phoenix Logs — Rise of Atriox I
- Halo 4, campaign level Requiem
- Data Drop, #5
- Halo: Reach Limited Edition, Intersystem News, LCDR Miranda Keyes Awarded Silver Star
- Dr. Halsey's personal journal, April 6, 2550
- Dr. Halsey's personal journal, June 3, 2550
- Halo: Warfleet, p. 31
- Halo Wars 2, Phoenix Logs — Rise of Atriox II
- Dr. Halsey's personal journal, November 23, 2550
- Halo: Escalation, Issue #17
- Dr. Halsey's personal journal
- Halo Encyclopedia (2022 edition), page 50
- Halo: Shadows of Reach, chapter 1