New Sparta (Spartans in Space)

New Sparta (referred to as Eris by Earth humans) is a dwarf planet in the outer portion of the solar that has been the home planet of the Spartans since 330 BC.

Pre-Spartan settlement
Before Spartan settlement, New Sparta was a barren planet completely covered in methane ice. New Sparta, much like the other dwarf planets within the outer solar system, have long orbits and therefore long winters.