HELIOS One

 is a Poseidon Energy solar plant and a refractor mirror that can provide energy to the Strip and other places. It contains a massive super laser, Archimedes II.

NCR has taken great interest in the plant, and have a technician named Fantastic working on getting the laser to function.

Appearances
appears in Fallout: New Vegas.

Behind the scenes
Archimedes is rumoured to have developed the plans for a 'death ray' super weapon. The weapon would harness the power of the sun through a series of mirrors and prisms, resulting in an intense beam of light that was intended to sink enemy ships. The solar mirrors of Helios One serve as a reference to (or perhaps an actual use of) that death ray.