From Halopedia, the Halo wiki
Belisk is a town on the planet Sargasso, a human colony planet governed by the Unified Earth Government. The town was built around a number of large-scale manufacturing plants belonging to Lethbridge Industrial.
By 2546, the Office of Naval Intelligence had invested a large amount of money in the town for Lethbridge's military-grade gear and munitions for both the UNSC and themselves. Sometime during that year, the Covenant assaulted the planet and sent a ground force down to destroy Belisk and cripple its production facilities. At least two Orbital Drop Shock Trooper squads, Alpha-Nine and Gamma-Six, were sent in to protect a Lethbridge facility and secure its research data, respectively.
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