Oxychloride Generation by Electrostatic Discharge (ESD) of Martian Dust and Detection by Infrared Spectroscopy

Abstract

Stable oxychlorides, mainly composed of ClO4–, ClO3–, or their mixture, are significantly enriched on the Martian surface (up to ∼0.5%) compared to Earth. ClO4– and ClO3– have different physicochemical properties and biological activities. They are also important candidates for in situ resource utilization (ISRU) and even the food sources of potential Martian lives. Therefore, it is of great scientific significance to determine the species of oxychlorides, especially the ratio of ClO4–/ClO3– on the Martian surface, not only for Martian environmental evolution and life search but also for Martian resource development. In this study, first, a simulation of oxychloride generation by electrostatic discharge (ESD) of the Martian dust storm was performed under simulated Martian conditions. Second, the spectral features of the Fourier transform infrared attenuated total reflection (FTIR-ATR) spectra and liquid transmission (FTIR-TR) spectra of ClO4– and ClO3– were characterized, and a quantitative model between their IR spectra and their concentrations was built. Finally, the concentration of ClO4– and ClO3– in the ESD reaction product under various reaction times and the ratio of ClO4–/ClO3– was detected and analyzed. Our results provide valuable information for the study of the origin of the mechanism, the scientific estimation of the abundance and the species of oxychlorides on the Martian surface, and even the feasibility of ISRU on the Martian surface.