RUBI is an experiment to investigate boiling phenomena which is carried out on the International Space Station (ISS) in 2019. This ESA-funded project offers European scientists and their associated colleagues a unique opportunity to gain a deeper understanding of the physical processes of boiling. The results of this project will not only be used for heat transport in weightlessness. Rather, the deeper understanding of boiling processes will allow a better prediction and design of heat transfer processes on Earth. These processes play a relevant role in a multitude of technical applications like power plant, refrigeration units, and chemical industry. But even every refrigerator at home or the air conditioning in the car use similar processes.