Introduction Over the last ten years, ESA has released six Announcements of Opportunity to exploit ERS and now Envisat satellite data, with the goal of fostering scientific knowledge and our understanding of the Earth’s environment. The primary objectives of all of the AOs were to support scientific research, stimulate the development of algorithms and products, and to support application demonstrations. In addition, they facilitated the transfer of scientific results into sustainable applications/services and supported the transfer of technology. By signing the ESA Terms and Conditions, the project leaders of the accepted AO proposals agreed to generate regular reports on their project’s progress. As a result, the achievements of the ERS-1 and ERS-2 mission projects have been published in more than 8000 papers or articles (Fig. 1), covering all of the Earth-sciences disciplines.