REXUS (Rocket Experiments for University Students) is a European student rocket program that allows university teams to perform scientific and technological experiments in near-space conditions. The program is operated by the German Aerospace Center (DLR) and the Swedish National Space Agency in collaboration with ESA, with launches taking place at the Esrange Space Center in northern Sweden. Each year, selected student teams fly their experiments on REXUS rockets, which reach altitudes of up to 90 km and provide several minutes of microgravity. After the flight, all experiments are recovered so that teams can analyze the collected data and draw scientific conclusions.

The main objective of the CAPILUX experiment is to study how liquids move and how they can be transported in microgravity using the capillary effect. The experiment focuses on fluid transport and passive valve behavior under microgravity conditions. The CAPILUX concept was presented by the RTU team at the ESA 17th REXUS/BEXUS Selection Seminar in Noordwijk, the Netherlands, where it was selected for flight. Over the next year, our goal is to bring the experiment to full flight readiness. The rocket launch is planned for March 2027.