 The Sentinel-2 mission, developed by the European Space Agency as part of the Copernicus program, is acquiring high spatial resolution optical imagery and has undergone calibration activities and validation after one year in orbit, with measured performances covering both top of atmosphere and bottom of atmosphere products, showing good quality in terms of radiometry and geometry, while providing an overview on next mission steps related to data quality aspects. This article was authored by Foran Gaskin, Catherine Buzanak, Olivier Thiepot and others.