Atmosphere Processors are large structures that are installed on planets with unbreathable or toxic atmospheres in order to convert the environment to a habitable one. This proprietary system creates a localized environment in the lowest atmospheric strata by mining the surrounding air and delivering electrostatic charge to correct the chemical composition of the planetary atmosphere. The system does this by converting toxic compounds into a breathable air ratio of approximately 1:3.1 oxygen-to-nitrogen ratio, depending on a colony’s oxygen needs. Once stable equilibrium is achieved, the AP continually monitors environmental gas compositions and corrects imbalances. By-products can often be isolated and condensed for use as fuel sources, industrial cleaning supplies or raw materials for manufacturing.
In 2179, the processor that was installed on the surface of LV-426 at the terraforming colony of Hadley's Hope exploded, leaving behind a large swath of destruction. Though an official reason for the processor's detonation was never precisely determined, the colonial marine unit sent to investigate the disappearance of the Hadley's Hope colonists discovered that emergency venting output was higher than normal. The surviving marines of the unit, Ripley, Bishop and Carter Burke now had approximately four hours to evacuate the area before a meltdown would trigger the blast. According to an estimate made by Bishop, when the processor finally detonated it left behind an area of destruction the size of Nebraska.