Investment in space systems must be sustained in order to meet the challenges of climate change, natural resources management and activities that affect the environment, such as maritime transport. However, it cannot be taken for granted that the funding will be forthcoming, not least because cost-benefit evaluations of future investments are far from straightforward. This chapter suggests how improvements might be made to the policy makers’ tool box for assessing and deciding on space-related investments. The first section discusses some key notions useful for defining space programmes (e.g. R&D, infrastructure, notion of costs); a second reviews methodologies used to evaluate benefits of space programmes in more detail, using specific case studies as illustrations; a third section develops an innovative infrastructure approach; and a final section provides prospective views on the use of risk management approaches for decision making in the field of space investments.