of the Telescope Optical Units is made by an international team from Italy, Switzerland and Sweden and coordinated by Roberto Ragazzoni at INAF (Istituto Nazionale di Astrofisica) Osservatorio Astronomico di Padova. The Telescope Optical Unit development is funded by the Italian Space Agency, the Swiss Space Office and the Swedish National Space Board. The PMC Science Management (PSM), composed of more than 100 experts, is coordinated by Prof. Don Pollacco of the University of Warwick and provides expertise for: The preparation of the PLATO Input Catalogue (PIC) Identifying the optimal fields for PLATO to observe Coordinating follow-up observations Scientifically validating PLATO's data products Objective The objective is the detection of terrestrial exoplanets up to the habitable zone of solar-type stars and the characterization of their bulk properties needed to determine their habitability. To achieve this objective, the mission has these goals: Discover and characterize many nearby exoplanetary systems, with precision in the determination of the planets' radii of up to 3%, stellar age of up to 10%, and planet mass of up to 10% (the latter in combination with on-ground radial velocity measurements) Detect and characterize Earth-sized planets and super-Earths in the habitable zone around solar-type stars Discover and characterize many exoplanetary systems to study their typical architectures, and dependencies on the properties of their host stars and the environment Measure stellar oscillations to study the internal structure of stars and how it evolves with age Identify good targets for spectroscopic measurements to investigate exoplanet atmospheres PLATO will differ from the CoRoT, TESS, CHEOPS, and Kepler space telescopes in that it will study relatively bright stars (between magnitudes 4 and 11), enabling a more accurate determination of planetary parameters, and making it easier to confirm planets and measure their masses using follow-up radial velocity measurements on ground-based telescopes. Its dwell time will be longer than that of the TESS NASA mission, making it sensitive to longer-period planets. Design Optics The PLATO payload is based on a multi-telescope approach, involving 26 cameras in total: 24 "normal" cameras organized in 4 groups, and 2 "fast" cameras for bright stars. The 24 "normal" cameras work at a readout cadence of 25 seconds and monitor stars fainter than apparent magnitude 8. The two "fast" cameras work at a cadence of 2.5 seconds to observe stars between magnitude 4 to 8. The cameras are refracting telescopes using six lenses; each camera has a 1,100 deg2