Airlock

An airlock is a device which allows passage between a pressurized space, such as the interior of a ship, and a vacuum, while minimizing the change of pressure in the vessel and loss of air from it. An airlock consists of a small chamber with two airtight doors in series which do not open simultaneously. Also, some airlocks on ground prevent compression, such as underwater excursions akin to the space compressions.

On UNSC spacecraft, hangar bays, lifepod or HEV launch areas are typically equipped with airlocks, used to prevent pressure loss from exposure to vacuum either due to a hull breach or the deployment of a lifepod or HEV. Halcyon-class cruisers, in particular, employ them as redundancy features for survivability during combat with Covenant warships. The also had an airlock large enough to cycle a fleet of dropships simultaneously.

The Covenant typically employ energy barriers in place of physical airlocks.

Known airlocks

 * Airlocks on the Pillar of Autumn
 * Cairo Station umbilical locks

List of appearances

 * Halo: Combat Evolved
 * Halo 2
 * Halo: The Fall of Reach
 * Halo: The Flood
 * Halo: Ghosts of Onyx
 * Halo: Uprising