Ariel is the third in a trio of dedicated exoplanet missions conceived by ESA focusing on various aspects of this rapidly evolving subject area. It will follow Cheops, which launched in 2019, and Plato, scheduled for launch in 2026.

Ariel will study the composition of exoplanets, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths.

It is the first mission dedicated to measuring the chemical composition and thermal structures of exoplanets, linking them to the host star’s environment. This will fill a significant gap in our knowledge of how the planet’s chemistry is linked to the environment where it formed, or if and how the type of host star drives the physics and chemistry of the planet’s evolution.

Observations of these worlds will give insights into the early stages of planetary and atmospheric formation, and their subsequent evolution, in turn contributing to the understanding of our own Solar System. They could help us find out whether there is life elsewhere in our Universe and if there is another planet like Earth.