Siege of the Atlas Moons
From Halopedia, the Halo wiki
The Siege of the Atlas Moons was a prolonged battle between the United Nations Space Command and the Covenant in 2538, around the moons of Atlas in the Valence system. During the siege, Danforth Whitcomb of the UNSC Navy participated in the engagement and gained a reputation as a great military commander for his accomplishments at the Atlas Moons.
While the moons were attacked by the Covenant, they were ultimately not glassed.
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