The European CHEOPS telescope (CHaracterising ExOPlanet Satellite) will look for transits or ‘mini-‘eclipses’ in the light curves of stars already thought to have planets orbiting around them, caused by the dip in brightness when their planet passes in front of them. Exoplanets thus detected—several of which are likely to be super-Earths less than 10 times more massive than our Earth—will then be analysed in fine detail to determine their size, mass, density and structure, and to ascertain if they have an atmosphere.

Selected for Europe’s Cosmic Vision 2015-2025 programme, the CHEOPS mission was proposed and is being led by a team of scientists at the University of Bern. It takes its inspiration from the European CoRoT mission for which CNES was prime contractor, using the same transit detection method and measuring techniques. Methods for processing raw data on the ground from the light curves ‘cleaned’ of noise and bias will be supplied by the LAM astrophysics laboratory in Marseille, like for CoRoT, with support from CNES.

CHEOPS is expected to observe between 500 and 1,000 nearby stars during its planned 3½-year mission.