Artist impression of Cheops

Studying planets around other stars will be the focus of the new small Science Programme mission, Cheops, ESA announced today. Its launch is expected in 2017.

Cheops – for CHaracterising ExOPlanets Satellite – will target nearby, bright stars already known to have planets orbiting around them.

Through high-precision monitoring of the star’s brightness, scientists will search for the telltale signs of a ‘transit’ as a planet passes briefly across its face.

In turn, this will allow an accurate measurement of the radius of the planet. For those planets with a known mass, the density will be revealed, providing an indication of the internal structure.

These key parameters will help scientists to understand the formation of planets from a few times the mass of the Earth – ‘super-Earths’ – up to Neptune-sized worlds.

Cheops is the first of a possible new class of small missions to be developed as part of ESA’s Science Programme.

Source: www.esa.int 19 Oct 2012