Operation: PALE SHADOW
From Halopedia, the Halo wiki
Operation: PALE SHADOW was a UNSC operation carried out on the human colony of Eirene in 2535. During the Covenant's assault on the colony, Kelly-087 triggered a reactor breach that led to a 50 megaton blast at a Covenant forward operating base. The destruction of the base allowed the city of New Kona to temporarily survive the battle.
Despite the success of Operation: PALE SHADOW, Eirene would later be glassed by the Covenant.
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