The ammonia tank transports ammonia working fluid to the International Space Station for the external Active Thermal Control System (ATCS). A collapsible metal bellows separates the liquid ammonia located outside the bellows from the nitrogen inside the bellows. The nitrogen pressure is regulated to drive ammonia out of the tank or back into the tank. The tank provides sufficient ammonia to fill the ATCS at startup and supplies makeup ammonia to the system as needed.
*Ammonia Tank and Accumulator