Liquid sloshing represents a major challenge for spacecraft design and operation. In low-gravity environments, a highly non-linear movement is produced due to the lack of stabilizing forces. This gives rise to significant disturbances that impact on the attitude control system of the vehicle. The employment of magnetically susceptible fluids may open an interesting avenue to address this problem, but their dynamics in microgravity remain practically unexplored. The UNOOSA DropTES StELIUM project aims at filling this gap by studying the lateral sloshing of ferrofluids in microgravity. Measurements of the free surface oscillations inside a cylindrical tank will be obtained as a function of the applied magnetic field intensity. These measurements will be employed to validate the numerical models developed by the authors and lay the foundations for the development of new magnetic sloshing control devices in space.