Help This article does not have enough inline citations or proper citation format. You can help Halo Nation by adding citations.
A "decapitation" capture (suicide?) mission. As if there was a choice.
Catherine Halsey's thoughts on the mission from her personal journal, August 27, 2552.[1]

Operation: RED FLAG was a planned UNSC ONI Section III operation conceived to put an end to the Human-Covenant war. The operation was never executed due to the Fall of Reach.[2]


RED FLAG was initially planned sometime before the November of 2549[note 1] and was originally intended as a last resort measure.[3]


The operation was to be executed in four phases.[4]


The first phase consisted of the disabling and capture of a Class-Five Covenant vessel. As such vessels only appeared in combat zones to collect Forerunner artifacts, this phase would require the use of a colony located on a planet with a high concentration of such items as bait. It would also require the retrofit of a cruiser, either Halcyon or Marathon-class, to be capable of conducting in-atmosphere operations and surviving the punishing firepower of a Covenant capital ship.

For the first phase, Dr. Halsey selected Captain Jacob Keyes to command the newly fitted cruiser UNSC Pillar of Autumn for his exemplary performance during the Battle of Sigma Octanus IV.


The second phase involved the boarding of the captured Covenant vessel by the SPARTAN-IIs, who would then neutralize the onboard defenses and take control of the ship. They, with help from a then-unidentified mission specialist, would then crack the navigation database of the ship and discover the location of the Covenant homeworld.

Halsey created Cortana for the role of mission specialist.


In the third phase, the Spartans would use the captured Covenant vessel to travel to the Covenant homeworld with the help of the mission specialist.


The fourth and final phase of the operation involved the infiltration of the Covenant homeworld and the capture of a Covenant Prophet for negotiating purposes. The UNSC hoped that by capturing a Prophet and holding it hostage, they could force the Covenant into agreeing to a truce, ending a war that the UNSC would most certainly have lost.


The highly advanced AI Cortana was activated on November 7, 2549, who was created for RED FLAG.[5] The UNSC Pillar of Autumn was refit specifically for RED FLAG in 2552.[6][7]

On August 14, 2552, Margaret Parangosky officially green lit the operation at Reach. However, the UNSC Army destroyed the only confirmed Class-5 vessel at Reach at the time; the Long Night of Solace. Despite this, Hieronymus Stanforth forwarded to Parangosky Cortana and Dr. Halsey's choices for the mission a week later on the 27th.[8] As well on that day, Dr. Halsey had a preliminary briefing with the recalled SPARTAN-IIs.[1]

Due to the severity of the Covenant attack on Reach, the Pillar of Autumn fled the planet and the operation unraveled.


Though the operation was never fully executed, the planning introduced new pieces of technology: the AI Cortana, the MJOLNIR Mark V, and an upgraded Autumn. Invaluable assets that would be used effectively in the Battle of Installation 04 and later influence large swathes of the UNSCDF.

Despite the Fall of Reach, the loss of most of the SPARTAN-IIs, and objections by Lieutenant Haverson and Cortana, John-117 still intended on continuing Operation: RED FLAG.[9]



  1. Cortana was originally created specifically for RED FLAG (Source) meaning it would have been planned sometime before her activation on November 7, 2549.