From Halopedia, the Halo wiki
Miridem was a human Inner Colony world of the Unified Earth Government. While comparatively smaller to the colonies in the Sol and Epsilon Eridani systems, Miridem was a strong, densely populated core world nonetheless.
In 2544, during the Human-Covenant War, Miridem fell in the way of the Covenant's path of destruction, becoming a target for the Third Fleet of Glorious Consequence. In the ensuing Battle of Miridem, Spartan-IIs were deployed to aid in the evacuation of Miridem's residents. While numerous evacuation craft attempted to flee the colony, most were destroyed before they even left the world's gravity well.
The protracted battle lasted for over two weeks, with the Covenant besieging Miridem. While attempting to evacuate Doctor Catherine Halsey, Sheila-065 was killed by the Sangheili Major Thel 'Lodamee and the doctor was eventually taken hostage. However, 'Lodamee's actions led to his battlegroup suffering severe casualties and ultimately prolonged the battle. Shortly after, Miridem was glassed by the Third Fleet of Glorious Consequence and the colony was declared lost by the United Nations Space Command. After Blue Team rescued the doctor, Operation: IRON FIST was enacted on Miridem. This operation involved at least one Spartan-II, John-117, and had the dual goals of asset denial and partial recovery of critical cyberinfrastructure assets on Miridem.
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