Airlock on the International Space Station

The airlock is a pressurized module with two separate chambers. It is the primary path on the International Space Station for spacewalks. The two cylindrical chambers divided by a hatch are the equipment lock and the crew lock. The equipment lock, the larger of the two, is designed as a storage area for spacesuits and is used by astronauts to suit up, stow all necessary gear and prepare for their excursion outside the station. The crew lock is the portal from which the spacewalkers exit the station. The crew lock contains lighting, handrails, and internal umbilical assemblies to provide power and communications before astronauts activate the internal battery power of their suit. (Credit: NASA)