The European Space Agency (ESA) is set to give existing orbiting probes, such as COROT and Kepler, a helping hand in studying super-Earths. Selected from 26 proposals, the CHEOPS (CHaracterising ExOPlanets Satellite) spacecraft is the first S-class (“small”) mission in the ESA’s Science Programme. A partnership between the ESA and the Swiss Space Office, CHEOPS will not seek out new exoplanets, but will instead target nearby, bright stars that are already known to have orbiting planets.
Slated for a 2017 launch, CHEOPS will operate in a Sun-synchronous low-Earth orbit at an altitude of 800 km (497 miles). To give an accurate measurement of the radius of an exoplanet under study, the spacecraft will use the transit method that observes the drop in brightness of the star that occurs when a planet crosses (transits) in front of it. The density of planets with a known mass can also be calculated, providing an indication of the planet’s internal structure.
This information will help shed light on the formation of planets ranging from super-Earths with a mass a few times that of Earth, up to Neptune-sized worlds. The spacecraft will also be used to identify planets with significant atmospheres and will be used to highlight targets for more detailed studies of exoplanet atmospheres by the next generation of telescopes in the pipeline, such as the ground-based European Extremely Large Telescope and the James Webb Space Telescope.
“By concentrating on specific known exoplanet host stars, CHEOPS will enable scientists to conduct comparative studies of planets down to the mass of Earth with a precision that simply cannot be achieved from the ground,” said Professor Alvaro Giménez-Cañete, ESA Director of Science and Robotic Exploration.
The video animation below shows how CHEOPS will operate.