UNSC Basra
From Halopedia, the Halo wiki
The UNSC Basra was one of the finest ships in the UNSC Navy. The Basra was stationed at Reach in August of 2552. When the Covenant attacked, the Basra was involved in the ensuing battle and irreperably crippled.
After the Battle, the Covenant moved most of the large hulks, including that of the Basra, into a large "graveyard" over Reach's northern pole. When Cortana and the Master Chief returned to Reach aboard the Ascendant Justice, Cortana saw the hulk of this ship, still floating in orbit.
NOTE: It is possible that if the Basra was identifiable, then it was not completely destroyed, and is yet salvagable.
