 The Centre is also responsible for a range of operations-related activities within ESA and in cooperation with ESA's industry and international partners, including ground systems engineering, software development, flight dynamics and navigation, development of mission control tools and techniques and space debris studies.ESOC's current major activities comprise operating planetary and solar missions, such as Mars Express and the ExoMars Trace Gas Orbiter, astronomy & fundamental physics missions, such as Gaia (spacecraft) and XMM Newton, and Earth observation missions such as CryoSat2 and Swarm (spacecraft).ESOC is responsible for developing, operating and maintaining ESA's ESTRACK network of ground stations.