K7-49 was discovered when the prowler UNSC Razor's Edge was trying to probe an enemy ship during the Battle of New Harmony. They followed the vessel through Slipspace and discovered the asteroid, along with a dozen partially constructed Covenant ships latched to an orbital shipyard. The volcanic activity on the planet was determined to be artificial; created by 30 high-output plasma reactors that liquefy metallurgical components. Each resulting element was refined, shaped, and shipped away for final assembly in the nearby warships.
Having confirmed the location of a major Covenant shipyard, the SPARTAN-III force designated Alpha Company was to disable as many on-site reactors as possible. If enough power plants were sabotaged, the liquid contents of the facility would solidify and permanently clog the Covenant's assembly area, rendering both it and the warships under construction worthless.
At 0700, 300 SPARTAN-IIIs from Alpha Company landed. Initial resistance to the SPARTANs was light, and after two days, seven reactors had been deactivated before the Covenant organized a proper counterstrike. These reinforcements were promptly destroyed. Over the next three days Alpha Company continued their advance, destroying 13 more reactors.
The Covenant reorganized and attacked yet again, with the SPARTANs trading fire with Elites and Banshees. On the seventh day, further Covenant reinforcements arrived. This united force was finally able to deliver an overwhelming, crushing blow to the stubborn infiltrator unit. The SPARTAN IIIs had lost their unit cohesion due to heavy fire and enormous casualties, while the surrounding Elites took up superior overwatch positions. By that point in the engagement, 89% of the planet had cooled due to the destruction of the nearby plasma reactors, enough for the Covenant shipyard to be permanently decommissioned. Alpha Company however, was completely cut off from their Calypso exfiltration craft, preventing the survivors from retreating.
Although the mission was a success and the K7-49 shipyard was disabled, all three hundred members of Alpha Company were killed in the fighting (other than those handpicked by Franklin Mendez). Despite the annihilation of the SPARTANs, UNSC High Command viewed the operation as a formidable strategic victory, ultimately saving millions of civilians from Covenant glassing. In fact, the training and deployment of future SPARTAN-III companies were accelerated as a result of Operation: PROMETHEUS.
- On July 27, at 0700, 300 SPARTAN-IIIs land on K7-49.
- On July 29, seven reactors had been disabled. A counterforce is organized by the Covenant.
- The Covenant force is neutralized. Over the next three days, 13 more reactors are destroyed.
- On August 1, A massive attack force is sent by the Covenant. Despite this, 7 more reactors are disabled.
- On August 2, additional Covenant reinforcements arrive. The asteroid has cooled enough for the shipbuilding operation to be canceled. Alpha Company was cut off from their extraction craft, preventing escape, and causing the deaths of all Spartans involved.
- Not all members of Alpha Company were killed in the battle. Many members were transferred shortly beforehand, including Carter-A259, Emile-A239, and Jun-A266, who served with Noble Team as of August 2552.
- The operation shares the name of Prometheus of ancient Greek mythology, a Titan and champion of mankind who stole fire from Zeus and gave it to humanity.
- This shares similar traits to the Battle of Thermopylae of 480 BC in which 300 Spartans fought and all perished.