Helios is a planet in a solar system of the same name. Helios is the closest and only planet revolving around Helios, making the planet just a lifeless desert. The Cyrannatar moved in, setting up the multiple large underground complexes, dubbed 'Helios I, II, and III.' The large complexes are all connected to each other, and feature many science experiments. There are no structures on the surface. As of recently, a small space station orbits Helios to ensure it's safety.
The Cyrannatar have kept their facility quiet, only top ranking military, political, diplomatic, and scientific leaders know about it. The official description of the planet, stated by the federal government, is 'A small desert world, devoid of all life. High temperatures. No cities. Population: 0.'
Helios' underground facilities have been known to conduct illegal experiments. These experiments have not been addressed by the government.