ESA’s first Earth observation mission dedicated to understanding our planet, the European Remote Sensing satellite (ERS-1), was launched into orbit on 17 July 1991 – almost 30 years ago today. At the time of its launch, the ERS satellite was one of the most sophisticated spacecraft ever developed and launched by Europe, paving the way for satellite technology in the areas of atmosphere, land, ocean and ice monitoring. Today, we look back at some of the mission’s key accomplishments.