ESA launches Cheops satellite to study discovered exoplanets in more detail

The European Space Agency ESA launched the Cheops satellite on Wednesday. The space telescope will further study discovered exoplanets for their atmospheric composition and their origin.

Cheops, an acronym for CHaracterising ExOPlanet Satellite, was launched on Wednesday from a Soyuz Frigate rocket from ESA’s Kourou launch site in French Guiana. The launch was delayed earlier this week. Cheops is put into a pole-to-pole Earth orbit. That is a little-used orbit, where the satellite can fly exactly on the border between light and dark. This makes it easier to make observations in the room itself.

Cheops is ESA’s first exoplanet mission. The telescope will take a closer look at exoplanets discovered by previous missions. The telescope does this with the so-called ‘transition method’, in which a star is studied by seeing what the object looks like that passes in front of it. This is the same method used in other exoplanet missions such as NASA’s Kepler mission. Cheops mainly looks at planets that are between so-called ‘super-Earths’ and Neptune in size. The data that Cheops collects is used, among other things, to calculate the density and composition of the planet. In some cases it is even possible to study parts of the atmosphere. Cheops also has to look at how small planets form. Astronomers now know very little about this process.

Cheops is a relatively small and cheap mission. The satellite is 1.5 meters wide and weighs 280 kilograms, and cost only 50 million euros – little money for such an astronomy mission. According to the ESA, Cheops is also primarily a preparation for future missions. The space agency wants to organize more advanced exoplanet missions in the future, which can look in even more detail at the planets that Cheops deems worthy of further study. These include the Plato mission, which should lead to a launch in 2023, and the Ariel mission in 2028. They should respectively search for liquid water and map the atmospheres.

Cheops was not the only satellite sent into space with the Soyuz. There were also four other smaller satellites on board. These include an astronomy satellite for the company CNES, and an Earth observation satellite for the Italian space agency.