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. If you get the laser to function, you can get a portable controller for the laser to help you in combat, and it rains down lots of lasers on your enemies.

Appearances
appears in Fallout: New Vegas.

Behind the scenes
Archimedes is rumored 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.

In its architecture and use of heliostats, the Helios One system appears to be an adaptation of the Solar One / Solar Two experimental "power tower" type concentrating solar power generating stations in Barstow, CA, or of their original prototype at Sandia National Laboratories in New Mexico.

In Greek Mythology, Helios is the Sun God.Thus, a good name for something that requires solar energy to operate.