DEFINITION:
It includes:

• Mission Operations: Addresses aspects related to the control and operations of space system elements (satellites, transfer vehicles, orbiters, landers, probes, rovers, etc.) and related ground segments, addressing the technologies associated with supporting systems and tools.
• Ground Systems (including software): Covers all elements and knowhow required for engineering of the facilities that connect the space segment with control centres. The application range covers high performance deep space stations to networks of small ground stations. It also includes mission control system software design, verification, validation and maintenance methods/tools and application of modern IT technologies to spacecraft operations, including Object Oriented Technologies.

(Source: ESA TD 9, ESA TD 12 and ESA TD 2C)