18/12/2019 (Agence Europe) – After 1 day's delay, the European Space Agency (ESA) confirmed on Wednesday 18 December the successful launch of the Cheops Space Telescope. The telescope was launched from the Guyanese space centre in Kourou (French Guiana) on a Russian Soyuz launcher. Cheops is a partnership between the ESA and Switzerland, with a significant contribution from 10 ESA Member States. This is the ESA's first mission dedicated to exoplanets. Its primary objective will be to determine the size of exoplanets already discovered using the transit method, i.e. by measuring the periodic luminosity variation of a star as a planet passes in front of it. Combined with the measurement of radial velocities, which makes it possible to estimate the mass of a planet, it will then be possible to accurately estimate the density of a planet and, consequently, whether it is rocky or not. (PH)