MOVIDA, A MICROBALANCE SYSTEM TO DETECT VOLATILES AND MONITOR CHARGING PROCESSES OF LUNAR DUST

In recent years the world's space agencies and several private companies all over the world are planning to return to the Moon. The Moon is a privileged location for space observations and investigation of fundamental questions related to the origin and evolution of our Solar System. Nevertheless, the Lunar environment can compromise instrument performance and cause important issues for human crews: it is thus extremely important to study and characterize it in terms of physical properties, granulometry and electric charge. The Moon surface is exposed to solar radiation as well as to solar wind, charged particles, galactic cosmic rays and high-speed micrometeorites, leading to different processes of dust charging. The interaction of the lunar surface with UV radiation and plasma results in the emission and re-absorption of photoelectrons and/or secondary electrons at the walls of microcavities formed between neighboring dust particles below the surface, resulting in unexpectedly large negative charges and strong particle repulsion forces sufficient to mobilize and lift off dust particles. In this framework, an innovative instrument based on PCMs (Piezoelectric Crystal Microbalances), named MOVIDA (Moon Volatile Investigator and Dust Analyser), is proposed. Its main scientific objectives are to study the lunar dust properties, to characterize the charging and levitation processes and to identify potential resources such as water or organic-rich materials. MOVIDA is composed by three units: the first one is an electronic box; the second one is based on quartz crystals equipped with built-in heaters and Resistance Temperature Detectors (RTDs), to measure volatiles and dust abundance; the third one, DEC (Dust Electrostatic Collector), is based on quartz crystals equipped with a capacitor to determine the properties of the lunar levitating dust. The instrument is under development by an Italian Consortium composed by INAF-IAPS, Politecnico di Milano and CNR-IIA and led by INAF-IAPS.