Archimedes I is a solar protection system for HELIOS One in Fallout: New Vegas.

FNV screenshot Helios laser

Archimedes II activated


Archimedes I (sometimes just referred to as "Archimedes" or the "Archimedes Plant Defense System") is the first version of a local based laser weapon developed by Poseidon Energy at HELIOS One. Archimedes I's security system uses a local based laser from the solar collection tower to destroy targets in the area around the plant.

When the player activates HELIOS One during the That Lucky Old Sun quest, they are given a choice to arm Archimedes I. This will automatically initiate a test run of the system, which will activate a laser strike from the tower on the area around HELIOS One. This will kill all the NCR soldiers outside the building, causing a decrease of NCR fame, but no Karma loss.


It should be distinguished from Archimedes II, the second iteration of the system, which is an orbital based laser system and can target any outdoor location in the Mojave Wasteland.


Reflector warning
Warning 1
Warning 2
Countdown warning
Countdown concluded


  • It is not necessary to divert power to Archimedes II during That Lucky Old Sun in order to activate Archimedes I. Archimedes I can be activated after selecting any of the first four power options from the HELIOS One mainframe terminal (any of them but the "Full Region, Emergency Power Level" option).
  • Archimedes I can be activated (once) at any time after HELIOS One comes back online, unless as mentioned above the player has selected "Full Region, Emergency Power Level".
    • If activated after the quest has been completed, Caesar's Legion will not take over HELIOS One even if all NCR soldiers are dead.
    • This will not activate Euclid's C-Finder, which requires diverting power to Archimedes II during That Lucky Old Sun.
  • Activating Archimedes will cause Arcade Gannon to leave you as a companion.
    • You cannot get him back after he leaves.
    • All of your items are returned upon him leaving you.

Behind the scenesEdit

The ancient writers Lucian and Anthemius of Tralles wrote that the Greek scientist Archimedes built a 'heat ray' weapon using mirrors to focus the sun's energy on enemy ships. It was purportedly used at the Roman Siege of Syracuse from 214-212 BC. Most scientists are skeptical that such a device would be practical or efficient; however, the machine's ultimate effectiveness (or ineffectiveness) may be deduced from the fact that the Romans ultimately succeed in taking the city.

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