Optical Constants of Martian Dust Analogs at UV–Visible–Near-infrared Wavelengths

Abstract We present an advanced light-scattering model to retrieve the optical constants of three Martian dust analogs: Johnson Space Center regolith simulant, Enhanced Mojave Mars Simulant, and Global Simulant. The samples are prepared have narrow particle-size distributions within geometric-optics domain. carry out laboratory measurements obtain distributions, shapes, diffuse reflectance spectra analogs deposited on a surface. Our framework includes ray-optics code compute scattering properties for individual particles, radiative-transfer treatment simulate irregular shapes particles taken into account in model. compare our derived imaginary parts refractive indices with those literature find that they much smaller than ones commonly used dust. A sensitivity study shows retrieved sensitive particle shape, which needs be accounted applications use different shapes. Finally, values validated by using them reproduce spectrum surface as observed Nadir Occultation Discovery instrument board ExoMars mission.