 The Sentinel-2 mission is a satellite program operated by ESA as part of the Copernicus Program of the European Commission. It is designed to acquire high-resolution optical images for Earth observation purposes. After one year in orbit, the mission's performance was assessed through validation activities. These activities included measurements of TOA and BOA products, which showed good quality in terms of radiometric and geometric accuracy. Next steps include further improvements to data quality, such as developing algorithms to detect clouds and snow, and improving the accuracy of the mission's products. This article was authored by Ferran Gaskin, Catherine Buzzenack, Olivier Thiepot, and others.