ESPRESSO, an exo-Earths hunter for the VLT

ESPRESSOis the next European exoplanetshunter. It will combine the efficiency of modern echelle spectrographwith extreme radial-velocityprecision. It will be installed at Paranal's VLT in order to achieve two magnitudes gain with respect to its predecessor HARPS, and the instrumental radial-velocityprecision will be improved to reach 10 cm/s level. We have constituted a Consortium of astronomical research institutes to fund, design and build ESPRESSOon behalf of and in collaboration with ESO, the European Southern Observatory. The project has passed the final design reviewin May 2013. The spectrographwill be installed at the Combined Coude Laboratory of the VLT, it will be linked to the four 8.2 meters Unit Telescopes through four optical "Coude trains" and will be operated either with a single telescope or with up to four UTs, enabling an additional 1.5 magnitude gain. Thanks to its characteristics and ability of combining incoherently the light of 4 large telescopes, ESPRESSOwill offer new possibilities in many fields of astronomy. Our main scientific objectives are, however, the search and characterization of rocky exoplanetsin the habitable zone of quiet, near-by G to M-dwarfs, and the analysis of the variability of fundamental physical constants. In this paper, we will present the scientific objectives, the capabilities of ESPRESSO, the technical solutions for the system and its subsystems, enlightening the main differences between ESPRESSOand its predecessors. The project aspects of this facility are also described, from the consortium and partnership structure to the planning phases and milestones.