The UNSC Armstrong was a ship in service with the UNSC Navy during the Human-Covenant war. It participated in the First Battle of Arcadia in February 2531, alongside the UNSC Pillar of Autumn, the UNSC Texas, the UNSC Belfast, and later the UNSC Spirit of Fire. Together with the Texas, Belfast, and Pillar of Autumn, the vessel engaged two Covenant Battlecruisers designated CCS-U321 and CCS-U624, catching U321 with its shields down and quickly destroying it. However, U624 engaged them immediately after, destroying the Texas and Belfast, and severely damaging the Armstrong and Autumn, causing the Armstrong to vent atmosphere.