This paper studies the impact of procurement on supplier firms. Specifically, we empirically investigate the direct and indirect mechanisms through which public procurement influences firms’ performance in the Italian space industry. Our research strategy involves conducting a survey of firms and analysing the results with econometric tools, and we interpret qualitative data from interviews as cross-validation. We found that space procurement generates two outcomes in firms: “intermediate outcomes”—i.e., learning, collateral innovation, and market penetration—and “final outcomes”—i.e., profit and sales, business development, and employment—and that the former mediate the impact of procurement on the latter. Our results offer insights into understanding the role of public procurement from the suppliers’ perspective.