The European Space Agency (ESA) launched a satellite early this morning aboard a Russian Soyuz rocket that took off from the Guiana Space Center in French Guiana. Atop the Soyuz is the so-called "Characterizing Exoplanet Satellite" (CHEOPS for short) that will deploy to orbit around Earth, where it'll have a better view of nearby stars that we've previously determined have planets in their own respective orbits.
CHEOPS will specifically be looking to spot the "exoplanets" (planets that are outside our own solar system) as they pass in front of their stars -- at which point they become observable because they block some of the light emitted from the distant suns. The satellite will be looking to track large planets in particular, with sizes ranging from larger than Earth to those closer to our own medium-large gas giants like Neptune.
The main thing it'll be looking to discover about these exoplanets is their density, or whether they're rockier like Earth and Mars, or more gaseous like Saturn, Jupiter and Uranus. That is a key ingredient in determining the potential habitability of a planet.
As of this morning, CHEOPS made contact with an Antarctic ground station, so it appears as though everything has gone to plan in terms of its orbital delivery and operations. The Soyuz rocket that delivered it also carried a number of other payloads, including additional science and research satellites to be used by the ESA, the French national space agency and more.