Firebase Bravo was the name of a UNSC Marine Firebase set up on Sigma Octanus IV, Grid 13 x 24, during the Battle of Sigma Octanus IV. It was partially dug into a hillside in a valley to minimize its visibility. The base itself was protected by a ring of sensors encircling the encampment. Radar and motion detectors linked to surface to air missiles and the compound itself was protected and surrounded by fixed gun emplacements and barbed wire.