The PLATO project, is part of ESA's program Cosmic Vision 2015–2025 which is the current cycle of ESA's long-term planning for space science missions.

PLATO is the next generation planetary transit experiment; its objective is to characterize exoplanets and their host stars in the solar neighbourhood. While it builds on the heritage from CoRoT and Kepler, the major breakthrough to be achieved by PLATO will come from its strong focus on bright targets, typically with mV=11. The PLATO targets will also include a large number of very bright and nearby stars, with mV=8.

The prime science goals of PLATO are:

the detection and characterization of exoplanetary systems of all kinds, including both the planets and their host stars, reaching down to small, terrestrial planets in the habitable zone;
the identification of suitable targets for future, more detailed characterization, including a spectroscopic search for biomarkers in nearby habitable exoplanets.

The PLATO mission was subject to three independent studies, two by industrial contractors and one by the PLATO PayLoad Consortium (PPLC). All three studies have been running in parallel and were completed simultaneously at the end of summer, 2009. The three concepts resulting from these studies differ significantly from one another, but have in common optical designs with very wide fields-of-view, and overall large collecting areas. Wide fields-of-view are required to obtain large samples of bright stars, while large collecting areas are necessary to reach the desired photometric precision. In all three concepts, this is achieved by using a collection of small, optically fast, wide-field telescopes, each with its own CCD-based focal plane. The light and centroid curves from each individual telescope unit are transmitted to the ground at the required cadence, where they are co-added to reach the desired precision.