The CHaracterising ExOPlanets Satellite (CHEOPS) is the first mission dedicated to search for transits of exoplanets by means of ultrahigh precision photometry on bright stars already known to host planets. By being able to point at nearly any location on the sky, it  provides the unique capability of determining accurate radii for a subset of those planets for which the mass has already been estimated from ground-based spectroscopic surveys. It  also provides precision radii for new planets discovered by the new generation of ground-based and space-borne transits surveys (Neptune-size and smaller).

CHEOPS was launched on 18 December 2019 as the European Space Agency (ESA)’s first “small-class” mission. The mission is the result of a partnership between ESA and a consortium of 11 European countries led by Switzerland. In Switzerland, the University of Bern is the mission lead and the University of Geneva hosts the Science Operations Centre. 

The CHEOPS team at the University of Geneva (scientific, technical, and administrative staff) has contributed to the development and the calibration of the instrument and his now running the mission operations (scheduling of the observations, data analysis and data archiving) and the international team of scientists exploiting CHEOPS data.