English: Cover is removed on the Ammonia Tank Assembly.
The primary function of the Ammonia Tank Assembly (ATA) is to store the ammonia used by the External Thermal Control System (ETCS). The major components in the ATA include two ammonia storage tanks, isolation valves, heaters, and various temperature, pressure and quantity sensors. There is one ATA per loop located on the zenith side of the Starboard 1 (Loop A) and Port 1 (Loop B) truss segments. Each is used to fill their respective ETCS loop on startup (loops are launched with nitrogen in the lines) and to supply makeup fluid to that loop. It also assists the Pump Module (PM) accumulator with ammonia inventory management, and provides the capability to vent the PM and ATA by connection to an external nonpropulsive vent panel. The length is 57 inches by 80 inches width with a height of 45 inches. A new ATA, with 600 pounds of Ammonia, weighs approximately 1,702 pounds.