Sebastian Grevsmühl is TEUS research associate at Pierre et Marie Curie University (UPMC) in Paris. He earned his doctorate in history of science at the Ecole des Hautes Etudes en Sciences Sociales in 2012. His research interests focus on the history of the geosciences during the nineteenth and twentieth century. For the TEUS project, Sebastian is focusing mainly on early French contributions to upper atmosphere research and environmental surveillance during the first two decades of the Space age.