The mission

Cheops is ESA's CHaracterising ExOPlanet Satellite. It is the first space mission dedicated to studying bright, nearby stars that are already known to host exoplanets, in order to make high-precision observations of the planet's size as it passes in front of its host star. It focuses on planets in the super-Earth to Neptune size range, with its data enabling the bulk density of the planets to be derived – a first-step characterisation towards understanding these alien worlds.

The launch

Launch date: 18 December 2019
Launch site: Europe's Spaceport in French Guiana
Launch vehicle: Soyuz-Fregat
Orbit: Sun-synchronous, dusk-dawn orbit at 700 km above Earth

1 .5 m size

280 kg mass

19 ×19 arcmin field of view

1 .2 Gbit/day data

Latest news

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[ Cheops ]

12 FEB. 2026

Cheops discovers late bloomer from another era

Scientists used the European Space Agency's Cheops satellite to discover that the planetary system around the star LHS 1903 challenges current planet formation theories with the unusual order of its planets. Surprisingly, the most distant outer planet might be rocky and seems to have formed later – in a different environment than the other planets around the star.

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[ Cheops ]

ARCHIVE CONTENT: 09 DEC. 2019

Cheops launch media kit

Download this media kit to learn more about the launch of Cheops, the Characterising Exoplanet Satellite, on 17 December 2019, and the science goals of the mission.

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[ Cheops ]

ARCHIVE CONTENT: 02 JUL. 2025

Clingy planets can trigger own doom, suspect Cheops and TESS

Astronomers using the European Space Agency’s Cheops mission have caught an exoplanet that seems to be triggering flares of radiation from the star it orbits. These tremendous explosions are blasting away the planet’s wispy atmosphere, causing it to shrink every year.This is the first-ever evidence for a ‘planet with a death wish’. Though it was theorised to be possible since the nineties, the flares seen in this research are around 100 times more energetic than expected.

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[ Cheops ]

ARCHIVE CONTENT: 08 FEB. 2023

ESA’s Cheops finds an unexpected ring around dwarf planet Quaoar

During a break from looking at planets around other stars, ESA’s CHaracterising ExOPlanet Satellite (Cheops) mission has observed a dwarf planet in our own Solar System and made a decisive contribution to the discovery of a dense ring of material around it.The dwarf planet is known as Quaoar. The presence of a ring at a distance of almost seven and a half times the radius of Quaoar, opens up a mystery for astronomers to solve: why has this material not coalesced into a small moon?

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Latest images

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[ Science ]

12 FEB. 2026

Artist impression of the planetary system around the star LHS 1903

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[ Science ]

27 JUN. 2025

Clingy planets can trigger own doom, suspect Cheops and TESS

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[ Science ]

02 JUL. 2025

Stellar flares blast the wispy atmosphere away from exoplanet HIP 67522 b (artist’s impression)

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[ Science ]

02 JUL. 2025

Exoplanet HIP 67522 b triggers flares from its host star (artist’s impression)

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Latest videos

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[ Science ]

10 JUL. 2023

The shiniest known exoplanet: LTT9779 b

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[ Science ]

13 FEB. 2023

Exoplanets in Motion: The 3D Printed Edition

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[ Science ]

31 AUG. 2018

Vibration test of the Cheops satellite: longitudinal shaking

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[ Science ]

30 NOV. 2022

Calling all space detectives to hack an exoplanet!

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Latest links

[ Media Advisories ]

10 DEC. 2019

Call for media: Cheops launch to study exoplanets

Cheops, ESA’s ‘Characterising Exoplanet Satellite’, is scheduled to be launched on a Soyuz-Fregat rocket from Europe’s Spaceport in Kourou, French Guiana, at 09:54 CET on 17 December 2019. 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.

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