mission

This term is defined in ECSS-E-ST-10-06C as
a possible instantiation of the mission statement in a mission concept

This term is defined in ECSS-E-ST-70C as
specific objectives to be achieved by a space system as characterized by its expected products in terms of quantity, quality and availability

This term is defined in ECSS-S-ST-00-01C as
set of tasks, duties or functions to be accomplished by an element