Basis
From Halopedia, the Halo wiki
Summary
Basis is the largest moon orbiting Threshold. Installation 04 was positioned between Basis and Threshold. After Installation 04's destruction, the Covenant heretics built a makeshift camp on Basis, amid the wreckage from the Halo.
There were several large gas mines on Basis, one of which the heretics used. It was prone to violent storms, possibly electromagnetic in nature. Upon entrance to the gas mine, the Arbiter and Half-Jaw discovered that Flood had infested the station. If Flood had been brought by the heretics or somehow drifted onto basis from Installation 04 is unknown.
