An alternative architecture for the PLATO Mission

International audiencePlaTO (Planetary Transits and Oscillations of stars) is one of the class M missions proposed to ESA for the Cosmic Vision 2015-2025 program. It aims to find exoplanets by the transit method and to understand the hosting stars by measuring their oscillations (asterosismology). The same wide field of view of about 1,800 deg<SUP>2</SUP> will be observed during 3 years to achieve high precision photometry for a large number of stars (> 250,000). 42 telescopes, each one having 4 CCDs of 3584 x 3584 pixels will be read every 25 seconds generating a huge amount of data which cannot be downloaded to Earth and represents a challenge for the classical software-based data processing solutions. We present in this paper an alternative architecture based on FPGAs for the payload of the PlaTO satellite. The capabilities of the FPGA allows to treat tens of megabits per second through a pipeline driven by the pixel arrivals so that no buffering nor high speed clocks are required. This allows for treating multiple telescopes with a single FPGA and drastically reduce the mass and power budgets. The software resources can then be used to perform complex processing. Our alternative concept thus achieves precision at the theoretical limit together with major system-level improvements on the satellite. It opens the opportunity to achieve the science requirements with a comfortable margin of about 20% or to observe more stars