Ark Galactapedia

Helios IV is the outermost planet from the sun of the Helios system, United Empire of Earth (UEE). Although it is covered in thick sheets of ice and lacks a substantial atmosphere, the UEE military operates a network of outposts on Helios IV, located deep underground. The purpose of these facilities has never been publicly stated. Locals speculate that they are used for black-ops training or secret research, but no evidence to support these claims has ever been found.