Operation: PROMETHEUS

Operation: PROMETHEUS was a high-risk mission ordered by the Office of Naval Intelligence that took place between July 27 and August 2, 2537. The operation saw the deployment of 300 Spartan-IIIs from Alpha Company to K7-49, an asteroid which served as a Covenant shipyard, in order to disrupt the enemy's operations there. The mission ended in a Pyrrhic victory: though the facility was disabled, all 300 Spartans were killed.

Prelude
K7-49 was discovered when the prowler managed to attach a telemetry probe to an enemy ship during the Battle of New Harmony. The UNSC discovered the asteroid after the ship's return there along with a dozen partially constructed Covenant ships and an orbital shipyard. The asteroid's apparent volcanism was artificial; it was created by high-output plasma reactors that liquefied metallurgical components. These were then refined, shaped, and shipped away for final assembly.

The Office of Naval Intelligence deployed the entirety of SPARTAN-III Alpha Company to the asteroid. The Spartans' mission was to disable as many reactors as possible so the liquid contents of the facility would solidify and permanently clog the machines, ruining the Covenant's capacity to produce the ship components.

The operation
At 0700 on July 27, 2537, 300 Spartan-IIIs landed on the asteroid. Initial resistance to the Spartans was light, and after two days, seven reactors had been deactivated before the Covenant organized a proper counterforce. The counterattackers were neutralized and, over the next three days, Alpha Company destroyed 13 more reactors.

However, the Covenant soon arranged a massive counterforce, with the Spartans trading fire with Sangheili and ground attack craft. More Covenant reinforcements arrived on August 2. The Spartans lost their unit cohesion in the battle, while the Sangheili took up superior positions with good cover. By then, 89% of the asteroid had cooled, enough to render the shipyard inoperative. The Spartans were cut off from their, preventing them from escaping. Ultimately, all 300 Spartans were killed.

Aftermath
Although the mission was a success and the K7-49 shipyard was disabled, the Spartans sustained 100% fatalities. Other than a small number of Spartans transferred to other units prior to the operation, these losses ended Alpha Company as an active fighting force. According to Lieutenant Commander Kurt Ambrose, the leader of the Spartan-IIIs, failure would have resulted in the destruction of all of humanity's Orion-side colonies.

Timeline

 * On July 27, at 0700, 300 Spartan-IIIs land on K7-49.
 * By July 29, seven reactors have been disabled. A counterforce is assembled by the Covenant.
 * The Covenant force is neutralized. Over the next three days, 13 more reactors are destroyed. Another, larger force attack force is sent by the Covenant.
 * On August 2, additional Covenant reinforcements arrive. The asteroid has cooled enough for the ship-building operation to be rendered inoperative. Alpha Company is cut off from their extraction craft, preventing their escape. All 300 participating Spartans are killed.

Trivia

 * The operation is an obvious allusion to the Battle of Thermopylae. 300 Spartans were present at both battles, both were suicide missions, both were fought in order to slow the enemy down enough for the respective sides to prepare and survive longer, and both resulted in the deaths of nearly all Spartan combatants.
 * The operation was likely named for Prometheus of ancient Greek mythology, a Titan and champion of mankind who stole fire from Zeus and gave it to humanity.

List of appearances

 * Halo: Ghosts of Onyx
 * Halo Mythos: A Guide to the Story of Halo
 * Halo: Fractures
 * Lessons Learned