Representatives of traditional and social media are invited to apply for accreditation to follow the launch live from ESA’s European Space Astronomy Centre (ESAC) near Madrid, Spain.

Cheops is ESA’s first mission dedicated to the study of extrasolar planets, or exoplanets. It is a partnership between ESA and Switzerland, with a dedicated consortium led by the University of Bern, and with important contributions from 10 other ESA Member States.

The prime contractor for the design and construction of the spacecraft is Airbus Defence and Space in Spain.

The mission 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.

Cheops will target stars hosting planets in the Earth- to Neptune-size range, yielding precise measurements of the planet sizes. This, together with independent information about the planet masses, will allow scientists to determine their density, enabling a first-step characterisation of these extrasolar worlds. A planet’s density provides vital clues about its composition and structure, indicating for example if it is predominantly rocky or gassy, or perhaps harbours significant oceans.

Unlike previous exoplanet satellites, such as the CNES-led Corot 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. It will also identify the best candidates for detailed study by future observatories.

The mission paves the way for the next generation of ESA’s exoplanet satellites – Plato and Ariel – planned for the next decade. Together, these missions will keep the European scientific community at the forefront of exoplanet research and will build on answering the fundamental question: what are the conditions for planet formation and the emergence of life in the Universe?

Cheops will lift off as a secondary passenger, hitching a ride on the Soyuz-Fregat that will deliver the first satellite of the Italian space agency ASI’s Cosmo-SkyMed Second Generation constellation into space. The launcher will also carry three ‘CubeSats’, small satellites based on standardised 10 cm cubic units, including ESA’s OPS-SAT – the world’s first free-for-use, in-orbit testbed for new software, applications and techniques in satellite control.

Experts will present the mission, its technical challenges and scientific goals during a dedicated programme for media at ESAC, which will include viewing the webcast from the launch site in Kourou.


About the European Space Agency

The European Space Agency (ESA) provides Europe’s gateway to space.

ESA is an intergovernmental organisation, created in 1975, with the mission to shape the development of Europe’s space capability and ensure that investment in space delivers benefits to the citizens of Europe and the world.

ESA has 22 Member States: Austria, Belgium, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Luxembourg, the Netherlands, Norway, Poland, Portugal, Romania, Spain, Sweden, Switzerland and the United Kingdom. Slovenia is an Associate Member.

ESA has established formal cooperation with seven Member States of the EU. Canada takes part in some ESA programmes under a Cooperation Agreement.

By coordinating the financial and intellectual resources of its members, ESA can undertake programmes and activities far beyond the scope of any single European country. It is working in particular with the EU on implementing the Galileo and Copernicus programmes as well as with Eumetsat for the development of meteorological missions.

ESA develops the launchers, spacecraft and ground facilities needed to keep Europe at the forefront of global space activities.

Today, it develops and launches satellites for Earth observation, navigation, telecommunications and astronomy, sends probes to the far reaches of the Solar System and cooperates in the human exploration of space. ESA also has a strong applications programme developing services in Earth observation, navigation and telecommunications.

Learn more about ESA at