Single-celled organisms – such as the freshwater alga Euglena gracilis – react sensitively to changes in their environment. Since biotechnologically and medically important substances with a broad range of applications can be obtained from this alga and it therefore plays an increasingly important role in biotechnology, we want to find out more about its orientation behaviour with regard to light and gravity. This is the only way to further improve the mass production of this alga in the future. The German ESA reserve astronaut Amelie Schoenenwald is supporting the University of Erlangen with its experiments during the parabolic flight campaign.