The Characterising Exoplanet Satellite, Cheops, will target 15 October to 14 November 2019 for launch.
Cheops will lift off on a Soyuz rocket operated by Arianespace from Europe's spaceport in Kourou, sharing the ride into space with a satellite that is part of the Italian Cosmo-SkyMed constellation. The two satellites will separate in turn into their own orbits soon after ascent, with Cheops operating in a low-Earth orbit at an altitude of 700 km.
The satellite will observe individual bright stars that are known to host exoplanets, in particular those in the Earth-to-Neptune size range. By targeting known planets, Cheops will know exactly when and where to point to catch the exoplanet as it transits across the disk of its host star. Its ability to observe multiple transits of each planet will enable scientists to achieve the high-precision transit signatures that are needed to measure the sizes of small planets. (learn more)