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.
The design of Cheops was driven by the need to precisely measure the ‘signal’ from exoplanet host stars. Precision is of particular importance because the transit signal can be extremely tiny for the smallest planets, and noise from the instrument itself can potentially obscure the transit. The instrument therefore needs to be as stable as possible, both in terms of keeping jitter to a minimum while observing the star in ‘stare and track’ mode, and in keeping cool to avoid thermally-induced noise.