Rather than look for more planets, Cheops will study some that have already been discovered in order to understand them better.

What will the Cheops mission try to accomplish?

Many of the exoplanets already spotted by astronomers were discovered by observing the gravitational tug — or “wobble” — that they exert on their home stars as they go around. This method allows astronomers to calculate the masses of the planets, but nothing else about their nature or composition.

Cheops will make precise measurements of the sizes of these planets by observing small dips in the brightness of their home stars as the planets pass in front of them — the so-called blink method. Along with the wobble, this data will allow astronomers to calculate the densities of these planets and determine whether they are rocky, like Earth, or fluffy, like gas clouds.

“Cheops will help us reveal the mysteries of these fascinating worlds, and take us one step closer to answering one of the most profound questions we humans ponder: are we alone in the Universe?” said Kate Isaak, the mission’s project scientist.