Preliminary results on the internal assessment study of the ESA Cosmic Vision mission PLATO

In order to better understand the properties of exoplanetary systems, the Cosmic Vision mission "PLAnetary Transits and Oscilliations of stars" (PLATO) will detect and characterise exoplanets using their transit signature in front of a large sample of bright stars as well as measuring the seismic oscillations of the parent star of these exoplanets. PLATO is a potential mission of the European Space Agency's Science programme Cosmic Vision 2015-2025, with a planned launch by the end of 2017. The mission will be orbiting the Sun-Earth second Lagrangian point, which provides a stable thermal environment and maximum uninterrupted observing efficiency. The payload will consist of a number of individual catadioptric telescopes, covering a large field-of-view on the sky. It will allow for continuous observation of predetermined star fields in order to detect many exoplanetary systems as well as smaller exoplanets with longer orbital periods. Such performance is achieved by high time-resolution, high precision, and high duty-cycle visible photometry using catadioptric telescopes with CCD detectors. In order to fulfill the specific science requirements, special attention is being paid to the opto-mechanical design of the payload, in order to maximize the field-of-view and throughput of the optical system, while minimizing the image distortion, mass and volume of each telescope to ensure compatibility with the launcher's maximum payload capability. Ground-based observations will complement the observations made by PLATO to allow for further exoplanetary characterization. The paper provides a summary of the preliminary results achieved by the ESA internal pre-assessment study.