Science diplomacy in the Global South: a case study of Brazilian participation in the PLATO mission

Studies on Science and Innovation Diplomacy have become increasingly established as a subfield of International Relations, with growing attention devoted to the role of Global South countries in international scientific cooperation. This article examines the participation of a Brazilian university in the European Space Agency's PLATO mission to explore how large-scale scientific collaborations can foster science diplomacy while simultaneously revealing the institutional and structural constraints faced by emerging countries. Drawing on a qualitative approach and a literature review, the single-case study contributes to the Research Topic "Linking Knowledge Across Borders: Science Diasporas and Global South Development" analyzing how a Brazilian laboratory contributed to the mission between 2009 and 2024. Initially conceived as a scientific cooperation project, the initiative gradually came to involve an increasing number of Brazilian state actors, expanding its significance beyond its original technical objectives. The findings show mechanisms by which international collaboration strengthened institutional relationships and diplomatic engagement, constituting a case of Science for Diplomacy and enhancing Brazil's international visibility. At the same time, the case highlights how Global North-South asymmetries, governance arrangements, and domestic institutional limitations shape the opportunities and challenges of the Global-South participation in large-scale scientific and technological initiatives.