An aerosol is a complex medium, sensitive to temperature and pressure conditions, sometimes chemically active, whose continuous phase is a gas in which liquid and/or solid phases are dispersed. It is naturally subject to the influence of gravity, which determines the settling speed of the particles it contains. Aerosols have many applications in the pharmaceutical and cosmetic industries (inhalers, sprays), in metallurgy (spray drying) and in agriculture (pesticides). From an academic point of view, they are the subject of intense research activity. The description of their evolution is, for example, a major issue in climatology. This is why CNES recently supported the development of an experimental facility for the investigation of cloud micro-physics in micro gravity conditions (Figure 1). The main goal is to produce aerosols and to follow their evolution with optical tomography microscopy in controlled thermodynamic conditions.