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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Cheops, the CHaracterising ExOPlanet Satellite, is ESA’s first mission dedicated to the study of extrasolar planets, or exoplanets. It will observe bright stars that are already known to host planets, measuring minuscule brightness changes due to the planet’s transit across the star’s disc.
Unlike previous exoplanet satellites, such as the CNES-led CoRoT (Convection, Rotation and planetary Transits) or NASA’s Kepler and Tess missions, Cheops is not a ‘discovery machine’ but rather a follow-up mission, focusing on individual stars that are already known to host one or more planets. The exquisite precision with which Cheops is able to measure planetary transits, together with the stability of the telescope, will enable astronomers to determine planet sizes both accurately and precisely.