The colony was discovered by an enormous Geth invasion fleet. The fleet consisted of the familiar Geth Dropship but also new, massive, unrecogizable ships classified as Geth Dreadnoughts. The planet's fleet, The Apollo Fleet, and defensive satellite systems engaged the fleet for three hours before nearly all of the orbital defenses were destroyed. Half of the remainder of the fleet was sent to the surface to start evacuating citizens while the satellites bombarded Geth Dropships from afar. Before all of Atlas's citizens could be evacuated, the first Geth dreadnought broke through the planets defense and began releasing Armatures and Colossi from its underside.