Public awareness of the urgent need for mitigating the environmental impacts of human activities is ever growing. This results in a more and more stringent public environmental legislation and an increasing public pressure. In this context, the European Space Agency (ESA), as a public sector intergovernmental organisation, wants to put the environmental concern as a priority in all its activities, as expressed in its Framework Policy on Sustainable Development. The first step in this direction is a deeper analysis and understanding of the environmental impacts of space programmes, to provide ESA with the necessary know-how to take a pro-active role regarding legislation on this topic and to drive technical and scientific innovation in the European space industry. In order to have a better knowledge of the environmental impacts of its activities and to be able to integrate environmental aspects during early design phases of space missions, ESA launched the project "Environmental impact assessment analysis", in the frame of the Clean Space initiative. BIO by Deloitte1 was awarded the contract for this GSP study