The UNSC Equilibrium is a Paris-class heavy frigate under the command of Commander Alexander Washington, a veteran of the Human-Covenant war. The frigate has seen much action, including the Seige of Haromony, the Battle of Installation 05, and the Original Discovery and Battle of Installation 03.
The first recorded discovery of this ring was some time between 2545 and 2550, by the UNSC Equilibrium and the Covenant Supercarrier Sacred Dawn, commanded by an early-rebelling faction of Elites, led by Ulna 'Fostusee. The faction of separatist elites united with the Equilibrium, which was originally outnumbered and outgunned by the Covenant fleet which had pursued them, to stop the Prophet of Mercy from activating the ring. Spartans Davis-063, Alfonzo-135, and Martin-B120 were deployed using ODST drop pods on to the surface of the ring, joined by hundreds of Separatist Elites on board Phantoms.
When the strike team landed on the ring, 20 kilometers from the Control Room, they were met with a ground force consisting of more than a hundred Elites, six Hunters, Forty grunts, and a Scarab.