The first Estonian research contract with ESA began on 26 May 2016 at ESA’s ESTEC site in the Netherlands. Estonia’s Tartu Observatory will lead an international team to ensure the quality of measurements taken over the sea by Sentinel-3’s ocean and land colour instrument. From left to right: Joel Kuusk (TO), Anu Reinart (TO), Christophe Lerebourg (ACRI-ST), Craig Donlon (ESA), Andrew Banks (NPL), Riho Vendt (Tartu Observatory), Kevin Ruddick (RBINS) and Tiia Lillemaa (TO).