UNSC Tharsis (Reach)

Were you looking for the UNSC Tharsis'', the ship of the same name destroyed at the Second Battle of Harvest?

The UNSC Tharsis was a UNSC destroyer. Tharsis saw action at the Battle of Reach where it was heavily damaged, although one of its fusion reactors remained intact. The Covenant moved the destroyer's hulk to the "graveyard" they established over Reach's northern pole.

When the UNSC-controlled Ascendant Justice returned to Reach following the Battle of Installation 04, Cortana considered merging the Tharsis with the captured Covenant vessel. However, ultimately the frigate was selected based on that ship's better condition and intact MAC gun. It is unknown why Cortana chose Gettysburg rather than Tharsis since the book fails to list any traits of the Tharsis past the fact that it was a destroyer.

Trivia

 * Tharsis is a volcanic plateau on Mars which derived its name from a biblical reference.