Mars Express is Europe’s first mission to the Red Planet. Since beginning science operations in 2004, the durable orbiter has given scientists an entirely new view of Earth's intriguing neighbour, and is helping to answer fundamental questions about the geology, atmosphere, surface environment, history of water and potential for life on Mars.

Mars Express shares a great deal of commonality with Venus Express and Rosetta in terms of the spacecraft platform, several of the instruments and the ground segment. Due to this commonality, the spacecraft was built and launched in record time and at a much lower cost than previous, similar missions to deep-space destinations.

Over almost 20 years, the high resolution camera on board Mars Express has sent back thousands of dramatic, 3D views of the Martian surface, covering everything from immense volcanoes and steep-walled canyons to dry river valleys, ancient impact craters and ever-changing polar ice caps.

While carrying out its own science objectives, Mars Express also provides relay communication services between Earth and various landers deployed on the surface of Mars by other space agencies, making the spacecraft a key piece of the international efforts to explore the planet.

Data collected by the orbiter instruments are transmitted to ESA's Estrack deep space antennas. From the ground stations, data are transferred to ESOC in Darmstadt, Germany, which adds spacecraft attitude and orbital data, and then retransmits the data to the various instrument's principal investigators (PI) for scientific processing and analysis. After about six months, all processed data are sent to ESA's European Space Astronomy Centre (ESAC), Spain, for storage in a publicly available Mars Express science data archive.

Information on the health and position of the spacecraft is included in a separate data stream. The Mars Express operations team at ESOC use this information, together with the forthcoming operational needs of the instruments, to work out new commands to instruct the spacecraft how to behave over the coming months. The new commands are uplinked via any ground station in order to keep a stack of several days' worth of commands pre-programmed in the on-board schedule.