Nature of exoplanets is the focus of European Space Agency’s next space mission

The European Space Agency will explore exoplanets—planets orbiting stars outside our solar system­—as its next mission. The agency selected the Atmospheric Remote-sensing Infrared Exoplanet Large-survey (ARIEL) from among three competing proposals, the agency announced on March 20. ARIEL will look at the chemical fingerprint of the atmospheres of the exoplanets it surveys—including concentrations of water vapor, carbon dioxide, methane, and exotic metal compounds­—and compare that to the composition of that planet’s nearest star. This information will help scientists understand what exoplanets are made of and how they form, as well as the range of exoplanet diversity. “ARIEL is a logical next step in exoplanet science, allowing us to progress on key science questions regarding their formation and evolution, while also helping us to understand Earth’s place in the universe,” says Günther Hasinger, the European Space Agency’s director of science. ARIEL is expected to look at hundreds of planets orbiting different types of stars. The satellite-based telescope will launch in 2028.