In March 2018, ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) was selected as the fourth medium-class mission in ESA's Cosmic Vision programme. It will address fundamental questions on what exoplanets are made of and how planetary systems form and evolve by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths.
ARIEL will focus on warm and hot planets, ranging from super-Earths to gas giants orbiting close to their parent stars. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System.
ARIEL will be launched on ESA's new Ariane 6 rocket from Europe's spaceport in Kourou in mid 2028. It will operate from an orbit around the second Lagrange point, L2, 1.5 million kilometres directly "behind" Earth as viewed from the Sun, on an initial four-year mission.
Currently the satellite's design is defined, which would lead to the "adoption" of the mission – presently planned for 2020 – following which an industrial contractor will be selected to build it. IWF will contribute to the on-board computer and participate in two scientific work packages.
Further information on ARIEL is found at ESA.