CHEOPS

CHEOPS (Characterising Exoplanets Satellite) is ESA's first Small-class mission under the Cosmic Vision science programme, selected in 2012 from 26 competing proposals. Rather than discovering new planets, it targets known exoplanets orbiting bright nearby stars, using high-precision transit photometry to measure their radii - and, combined with ground-based mass estimates, their bulk density and likely composition - for worlds ranging from super-Earth to Neptune in size.