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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Artist impression of a small, rocky planet – perhaps one flooded with lava – transiting across the face of its parent star.
ESA’s Characterising Exoplanet Satellite, Cheops, will study known transiting planets to build up precise measurements of their size. Together with known information about the mass of the planet, Cheops will allow the density of the planet to be estimated. This will constrain the planet’s possible composition and structure, indicating for example if it is predominantly rocky or gaseous, or perhaps harbours significant oceans. Cheops will focus particularly on bright stars hosting Earth- to Neptune-sized planets. This first-step characterisation of these worlds – many with no Solar System equivalents – is a critical process towards understanding the formation, origin and evolution of exoplanets in this size range.