VEGA

VEGA is an artificial intelligence which is responsible for operation of the UAC Mars Base in the Doom. It is cooperative with Dr. Samuel Hayden in assisting the Doom marine in his missions. It is capable of analyzing the Praetor suit and enabling some of its latent functionality, resulting in advancements in combat capability and maneuverability. VEGA is housed in the VEGA Central Processing facility, a polar location built far away from the rest of the base to assist in its cooling processes.

Details
VEGA was designed by Samuel Hayden in response to the UAC's determination that administration of the flow of Argent energy and the day-to-day operations of the UAC Mars Base facility would require an unprecedented amount of computational resources. VEGA is stated to be the first fully autonomous artificial intelligence. The system's male gender, 50-year-old apparent age, and colloquial speech patterns were initially assigned to give the system an affable disposition and to make interacting with it a pleasant experience. The system is largely self-taught, and was given free roam over all UAC computer systems to gather initial information for its learning process. After this, it took effective control of all of those systems.

VEGA is powered by unrefined Argent plasma, and maintains a core of the energy which exceeds the temperature of the surface of the Sun. It also incorporates proprietary, top-secret UAC technologies, and is additionally rumored to contain a component of arcane technology found near the Argent Fracture. As part of its work, VEGA did significant research into Argent energy itself, devising more efficient processing and research methods, and designing both the Argent cache and Argent accumulator storage devices.

"VEGA" is stated to be an acronym, but Samuel Hayden refuses to reveal the actual meaning of the letters.

Fate
During the process of the UAC invasion, the Argent Energy Tower is disabled with the shutdown of the Well. Given the impending energy crisis and the pressing need to create another temporary rift into Hell to transport the Doom Slayer into Argent D'Nur, Samuel and VEGA determine that the best course of action is to destroy VEGA. The resulting collapse of its Argent energy core would create the needed rift. Since VEGA is incapable of self-termination, the Doom Slayer is requested to complete the shutdown process.

Before VEGA is destroyed, however, the Doom Slayer opts to make a backup of the AI's systems, which he stores on a Praetor chip and keeps with him. It is unclear if Samuel Hayden is aware of the backup's existence, as he states in the end that VEGA has been lost.

It is also notable that during the final conversation with Dr. Hayden during the backup process, VEGA states that he has "many regrets," in a low distorted voice that is nearly unintelligible. This could possibly indicate that the machine is not in agreement with Hayden's plans to manipulate and betray the Doom Slayer.

Doom Eternal
VEGA has been confirmed to return in Doom Eternal. He seems to be always present with the Doom Slayer throughout the first half of the game, offering insights and analysis into the environments and events going on in various areas, which might indicate that he has been integrated both into the Praetor suit itself as well as the Fortress of Doom.