The European Space Agency (ESA) has officially adopted its Ariel mission, set to investigate the atmospheres of over 1,000 exoplanets. Launch is slated for 2029 from Kourou, French Guiana.
Astronomers have cataloged more than 4,000 exoplanets to date. Now, the focus shifts to detailed studies of these distant worlds. ESA's CHEOPS mission (CHaracterising ExOPlanet Satellite), launched on December 18, is already determining precise diameters, masses, and densities of transiting planets.
ESA's next endeavor, Ariel (Atmospheric Remote-sensing Infrared Exoplanet large-survey), will probe the atmospheres of 1,000 known exoplanets, revealing their thermal profiles and chemical compositions.
Chosen in 2018 under ESA's "Cosmic Vision" program, Ariel received formal approval from the agency's Scientific Programme Committee on November 12 following rigorous study phases.
At its core is a 1.1-meter telescope operating in visible and infrared wavelengths. Onboard spectrometers will scrutinize exoplanet atmospheres—focusing on super-Earths and hot gas giants—during transits in front of or behind their host stars.
These tools will detect potential biosignatures like water vapor, carbon dioxide, and methane, while tracking seasonal changes. France's ESA contributions, led by CNES, CEA, and CNRS, include designing, building, and delivering the AIRS spectrometer.
The prime contractor will be selected in 2021. Ariel will launch aboard an Ariane 6 rocket from Kourou, French Guiana, positioning at the Sun-Earth L2 point, 1.5 million kilometers from Earth.
ESA also eyes a 2026 launch for PLATO (PLAnetary Transits and Oscillations of stars), a space observatory targeting Earth-like exoplanets around nearby stars.
Meanwhile, NASA's James Webb Space Telescope, launching next October, will analyze nearby exoplanet atmospheres to assess habitability.
