Missing in action

Missing in Action, better known as MIA, is a casualty classification used by the United Nations Space Command that refers to members of the UNSC who has been reported missing following a combat mission and whose status as to injury, capture, or death is unknown. Missing combatants must not have been otherwise accounted for as either Killed in Action or a prisoner of war.

When SPARTAN-IIs are killed, they are reported as Missing in Action or Wounded in Action to create the illusion that Spartans never die. This helped boost morale in the UNSC. SPARTAN-IIIs are not normally subject to this, as the very existence of the program remains classified. However, at least two were listed as such in accordance with the tradition by Kurt Ambrose.

Notable examples

 * James-005 - Sent spinning into space during the Fall of Reach. Lost contact shortly thereafter and no sign of him was detected ever again. Presumably deceased.
 * Alice-130, Jerome-092, Douglas-042 - Declared Missing in Action after the was left stranded in space following the Battle of Trove. The Spirit of Fire eventually declared "lost with all hands" on February 10, 2534. As of 2559 are active on Installation 00.
 * Crew of the - Went Missing in Action following the Battle of Trove when the Spirit of Fire's FTL reactor was sacrificed to destroy Trove and its fleet of s. Declared "lost with all hands" on February 10, 2534. As of 2559, active at Installation 00.
 * Kurt-051 - Went Missing in Action during a mission in 2531. In reality abducted for the SPARTAN-III program. Died during the Onyx Conflict in 2552.
 * Randall-037 - Went missing in 2532 during the Battle of Vodin. Survived a fall from the planet's skyhooks and settled on the planet for the next ten years until the UNSC reestablished contact with Vodin. Refused to rejoin the Spartan program and had many of his augmentations reversed. Died during the Mission to Alpha Shard in 2556.
 * Sheila-065 - Declared Missing in Action in 2544. Died in the Battle of Miridem, witnessed by Doctor Catherine Halsey.
 * Sergeant Ghost - Declared Missing in Action during the Algolis Invasion after sacrificing himself to use the prototype powered armor to hold off the attacking Covenant forces. Killed when the armor self-destructed per his orders.
 * Kelly-087 - Declared Missing in Action by John-117 after she was abducted by Doctor Catherine Halsey. No longer considered MIA after the UNSC gained control of the Sarcophagus shield world where she had been taken.
 * John-117 - Disappeared after the Battle of Installation 00 when the split in half, leaving him trapped in deep space in the rear half of the ship. Considered Missing in Action due to the fact that there was no evidence that he died, despite Terrence Hood's quote, "hard to believe he's dead." Resurfaced in 2557 during the Battle of Requiem to help the  against Jul 'Mdama's Covenant. Returned to Earth following the New Phoenix Incident and was no longer declared Missing in Action.
 * Doctor Henry Glassman - Activated one of the Requiem slipspace artifacts, was pulled in and vanished, apparently killing him. In reality, transported to the surface of Requiem where he was captured by Covenant forces and put to work at "Librarian's Rest." Escaped after inadvertently activating a protective shield at the shrine and fled with Spartan Gabriel Thorne who had suffered a similar fate. Both later rescued by Fireteam Majestic with Glassman later being returned by Pelican to the Infinity.
 * Science Team Gagarin - Vanished without a trace after activating Forerunner technology at "the Refuge." Despite clues being found on Gagarin's computers by Fireteam Crimson, Gagarin was never located again and remains Missing in Action. Spartan Jared Miller speculated that they had suffered the same fate as Doctor Henry Glassman who had similarly vanished after activating one of the Requiem slipspace artifacts. However, Glassman had been found and captured by the Covenant on Requiem while Gagarin was never seen again.
 * Spartan Gabriel Thorne - Went Missing in Action after activating one of the Requiem slipspace artifacts like Doctor Henry Glassman which transported him to "the Cauldron." Captured by two Sangheili Storm after a fight. IFF tag found by Fireteam Crimson at "the Cauldron" along with signs of the struggle. Tracked to the "Quarry" where the trail vanished. Eventually detected again by Roland as he was transported to "Librarian's Rest" where Thorne managed to break free and escape with Glassman. Eventually rescued by Fireteam Majestic from Gek 'Lhar and no longer declared Missing in Action.
 * Icebreaker squad - Declared Missing in Action at some point during the Requiem Campaign. Found alive by Fireteam Crimson in "Lockup" and rescued during Crimson's own escape. Those who survived the following fight with Covenant forces fled "Lockup" in a stolen Phantom.
 * Fireteam Switchback - Vanished without a trace while investigating a Covenant dig site during the Requiem Campaign, leaving behind only their blank IFF tags. Later found alive, aside from Spartan Cara Costabile, after broadcasting an SOS over Covenant frequencies for some time in the "Warrens." Rescued by Fireteam Crimson and Fireteam Lancer during a mission in the area and extracted to the Infinity by Pelican.
 * Gray Team - Considered Missing in Action by Frederic-104 in November 2552 after they had been out of contact for over a year on a mission far outside the reaches of UNSC space. Actually went Missing in Action in December 2552 following Operation: SUNSPEAR where they destroyed the planet Glyke and were left adrift in its ruins in cryo chambers in their lifeboat. Recovered in 2558 by Fleetmaster Rojka 'Kasaan then freed from their cryo chambers by Melody Azikiwe during the Carrow Conflict. Reestablished contact with UNSC forces aboard the following the battle and were no longer Missing in Action.
 * Ferrets - Missing in action and presumed dead for more than two years before reappearing during Operation: WOLFE. In reality working deep undercover in the Keepers of the One Freedom.

Trivia

 * During the video log in the level 343 Guilty Spark, the automated video recorder regards Wallace A. Jenkins as possibly MIA due to the sudden termination of his recording as a result of his infection by the Flood.