The European Space Agency (ESA) is Europe’s gateway to space. Its mission is to shape the development of Europe’s space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world.
Find out more about space activities in our 23 Member States, and understand how ESA works together with their national agencies, institutions and organisations.
Exploring our Solar System and unlocking the secrets of the Universe
Go to topicProtecting life and infrastructure on Earth and in orbit
Go to topicUsing space to benefit citizens and meet future challenges on Earth
Go to topicMaking space accessible and developing the technologies for the future
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Galileo sensor stations, reversing the way satellite navigation usually operates, work together to pinpoint a Galileo satellite’s orbital position, its clock rate and signal health. Sensor station data gets fed through to the twin Galileo control centres so a set of corrections can be compiled. These corrections are uplinked to the satellites by Uplink stations every 100 minutes or less, for rebroadcast within the Galileo signal, keeping the system sufficiently aware. Telecommands to the satellite platforms are uplinked by dedicated Telemetry, Tracking and Command (TT&C) stations.