"A tous, de DDO — attention pour le décompte final!" For the European Space Operations Centre these words are what "Lights! Camera! Action!" are to a filmmaker. Seconds after separation from the launcher — the most exciting moment of the whole mission — the spacecraft becomes the responsibility of the staff and contractors at ESOC.

Critical mission phases

As soon as the first data is acquired, the complex operations of the Launch and Early Orbit Phase (LEOP) begin. LEOP includes the solar array deployment, which consists of the transfer of the spacecraft to its final orbit and the gradual switch-on of the payload. Once the proper functions of the satellite are confirmed, staff at ESOC monitor the routine operations of the craft to ensure that the spacecraft conveys its products and meets mission objectives.

Main Control Room at ESOC in critical LEOP

Since its creation in 1967, the European Space Operations Centre (ESOC) in Darmstadt (D) has planned missions, operated more than 60 satellites and ensured that spacecraft meet their mission objectives. The mandate of ESOC is to conduct mission operations for ESA satellites and to establish, operate and maintain the necessary ground segment infrastructure.

Detailed mission preparations

Complex flightpath of ESA's comet chaser "Rosetta"

ESOC's involvement in a new mission normally begins with the analysis of possible operational orbits or trajectories and the calculation of the corresponding launch windows—selected to make sure that the conditions encountered in this early phase remain within the spacecraft capabilities. The selection of the operational orbit is a complex task with many trade-offs involving the scientific objectives of the mission, the launch vehicle, the spacecraft and the ground stations. Once the final orbit has been selected, the ground stations, which are used to communicate with the satellite, are selected according to the mission phase and what has to be done.

The variety of orbits and conditions require that ESOC engineers and maintains a versatile global network of ground stations in correlation with the supporting communication systems, known as the Ground Stations Segment. Very often missions have special requirements, which cannot be covered by the Ground Segment services; thus, significant integration and development of operating stations provide a smooth environment for operating spacecraft. Thanks to this versatile network of ground stations, ESOC is capable of supporting almost any type of mission, from Low-Earth Orbit to interplanetary.

Worldwide network of ground stations

Ground station in New Norcia (Australia)

Over the past few years, ESOC’s mandate has evolved to allow the extension of availability of operational infrastructure and expertise to the general competitive industry. The term operational infrastructure includes ESOC ground segment elements and related facilities, which are established for use during several projects. The infrastructure consists of laboratories, environmental test facilities, ground stations, operational control centres, communication networks, information systems, information technology infrastructure as well as buildings and associated facilities.

Working with Industry

ESOC, and ESA in general, work closely with European industry to advance the state of European technology in the areas of spacecraft operation and communications. This is done by placing research and development contracts and studies, and by transferring the knowledge and experience during the execution of these contracts. ESOC has a substantial base of strategic assets and depth of expertise that have benefited many of its international partners.