Planetary Transits and Oscillations of stars (PLATO) mission will be launched into the 'L2' virtual point in space - 1.5 million kilometres beyond the Earth, as seen from the Sun - and will monitor thousands of bright stars over a large area of the sky.
The satellite will search for tiny, regular dips in brightness as their planets cross in front of the stars, temporarily blocking out a small fraction of the starlight.
In addition, PLATO will also investigate seismic activity in some of the host stars, and determine their masses, sizes and ages - with unprecedented accuracy - and helping to understand the entire exoplanet system.
The ESA Science Programme Committee meeting on June 20 agreed to the adoption of the PLATO mission, following its selection in February 2014. This means it can move from a blueprint into construction.
In the coming months, industry will be asked to make bids to supply the spacecraft platform. Its payload and control and analysis software will be constructed by agencies and institutes across Europe, researchers said.