Chi Ceti IV
From Halopedia, the Halo wiki
Summary
The Chi Ceti system is home to planet Chi Ceti IV, on the very fringes of the outer colonies. The planet has a top secret installation on its surface, the Damascus Testing Facility, where the SPARTAN-IIs were upgraded with their Mark V MJOLNIR armor. The facility was abandoned, and it being the only human installation on the planet, it is unlikely that the planet was destroyed by the Covenant.
