Many space-related impact studies have been carried out in the past, but there is no conclusive, comprehensive evaluation of the economic and social effects of public investments in space. Such evaluations are not easy to perform, for several reasons: the space sector is not a recognised category in official statistics; social benefits, which are likely to be very important, are hard to assess; and impacts from R&D are complex and occur in the long term. However, important steps can be made towards better evaluation of impacts. The full set of impacts of space investments may be simultaneously evaluated from both a ‘bottom-up’ and a ‘top-down’ perspective. In the bottom-up perspective, each effect is measured separately, while the top-down ...