Within the frame of overall engineering standards for space missions, this european standard contains the basic rules, principles and requirements to be applied to the engineering of the ground segment and mission operations, which form an integral part of the overall system implementing a space mssion. This European Standard includes development of ground segment, operations preparation activities, mission planning activities, mission evaluation activities, the conduct of operations proper, and all post-operational activities. The ground segment comprises the ground systems (i.e. all ground facilities, hardware and software) and all operational aspects such as personnel and related data repositories required on ground to perform mission operations. For reasons of recognized commonality, ground segment within the meaning of this European Standard includes those elements and facilities requried for the purpose of implementing the mission and fulfilling the missions requirements while the relevant space segments are in-orbit. It covers ground elements used for purposes of assembly, integration and verification of the space segment, to the extent needed for ground segment end-to-end verification activities. It also covers elements integrated into the groudn segment after completion of space segment AIT; spece segmetn AIT proper being considered outside the scope of this standard.