From Halopedia, the Halo wiki
2551 was a year in the 2550s in the 26th century.
- As part of Project CHRYSANTHEMUM, the SPARTAN-IIIs of Gamma Company begin their week-long augmentation process on the UNSC Hopeful in Sector K-009 folllowing its departure from Reach.
- The Hopeful returns to Reach following the Spartans' augmentation procedures.
- Before May, the CAS-class assault carrier Enduring Conviction, led by Let 'Volir, faces against the UNSC. During the battle, the Enduring Conviction performed impressive evasive maneuvers.
- Dr. Catherine Halsey undergoes the Hemley & Aubourn Behavior Analysis; the results make ONI increasingly wary about her reported unreliability.
- At 0720, as part of Operation: GYPSUM UNSC forces, including Sergeant Sigrid Eklund and M9 Wolverines, clear out the Caravelle province on Concord.
- Sigrid Eklund reports to Commander Renna regarding the events of Operation: GYPSUM indicating its success.
- On Concord; Operation: SHARP ANGLE is noted as confirmed, and Operation: OFFSET EYE is noted as pending.
- Operation: OFFSET EYE is accomplished by NOBLE Team on Corcord's Hinterlands region. Rosenda-A344 is transferred to other clandestine operations, while the rest of NOBLE Team is tranferred to Fumirole.
- The Car & Pilot Magazine releases its December 2551 Edition. This includes a review of the new 2553 edition of the Civilian "Hog".
- Pawel Czernek and John Tippett enter active service with the UNSC Marine Corps.
- Concord is attacked by the Covenant; the colony survives largely intact. The Venator MJOLNIR [GEN1] variant gains prominence in the attack.
- Gray Team is deployed on a mission against a Covenant facility within humanity's former territory.
- The Battle of Meridian ends. Meridian is glassed and Chalybs Defense Solutions facilities on the moon are abandoned. The Covenant discovers a Luminary on Meridian that leads to Earth.
- The UNSC Iroquois begins construction.
- Veta Lopis' mother dies.
- The M11 combat knife is manufactured by the Watershed Division.
- Halo Encyclopedia (2022 edition), page 108
- Halo: Ghosts of Onyx, page 101
- Dr. Halsey's personal journal, February 20, 2551
- Dr. Halsey's personal journal, February 27, 2551
- Halo Wars 2 - Phoenix Logs: Rise of Atriox III
- Data Drop 3
- Halo Encyclopedia (2009 edition), page 94 (2011 edition)
- Bungie.net: Bungie Weekly Update, 1/29/10
- Halo Waypoint, Halo Infinite: Season 02 Lone Wolves - Story & Intel (Retrieved on Oct 9, 2022) [archive]
- Bungie.net: AMG Civilian Hog Review
- Halo 4, MJOLNIR/Venator armor description
- Halo Waypoint - Canon Fodder: Bits & Pieces
- Halo Waypoint: Catalog Interaction
- Halo 2: Anniversary, Terminal 1
- Halo Mythos, page 82
- Halo: Last Light, page 365 (Google Play edition)
- Halo: Official Spartan Field Manual, p. 182