Defense of Mars

The Battle of Mare Erythraeum was an engagement of the Human-Covenant War in late 2552 where UNSC Army forces led by Colonel James Ackerson fought the Covenant on Mare Erythraeum on the surface of Mars. It occurred simultaneously with the Covenant's prolonged invasion of Earth and resulted in a Covenant victory. After the UNSC's eventual defeat, the Covenant began to concentrate more of their forces on Earth, although Ackerson's work in this battle helped buy UNSC ground forces on Earth precious time. During or after the engagement, Colonel Ackerson was taken prisoner and taken aboard the Triumphant Declaration.