The Chi Ceti system is a planetary system located in the far reaches of UNSC-controlled space, approximately 80 light years from Earth. It was home to the planet Chi Ceti IV, which housed the Damascus Testing Facility where the MJOLNIR Powered Assault Armor was first created.
- Main article: Battle of Chi Ceti
In 2525, the Battle of Chi Ceti was fought here between the UNSC Commonwealth and the Covenant CRS-class light cruiser Unrelenting. The facility on Chi Ceti IV was evacuated shortly thereafter, along with the MJOLNIR armor. In this battle, the Spartans successfully destroyed the Covenant ship, though Samuel-034 died in the process. Chi Ceti IV apparently survived further Covenant attacks because it continued to supply MJOLNIR variants until well after the war. The planet's volcanic moon was also home to a UNSC base, where teams from the Materials Group sought to mine the tectonic ground.
Chi Ceti is a UNSC-controlled system with several planets and satellites.