Combat Team Sierra
From Halopedia, the Halo wiki
Combat Team Sierra was a United Nations Space Command Marine unit stationed aboard the UNSC Pillar of Autumn. In the abandonment of the warship, it was to hold off the invaders until all non-bridge operations personnel and Combat Team Alpha through Combat Team November escaped in lifepods, and then retreat to an evacuation station aboard the Pillar of Autumn during the Covenant boarding action.
