Dusty Mafic Rocks Along the Path of Chang'E‐4 Rover: Initial Analysis of the Image Cubes of the Onboard Visible and Near‐Infrared Imaging Spectrometer

Abstract

AbstractThe Yutu‐2 rover of Chang'E‐4 encountered four special rocks along its path. The onboard Visible and Near‐infrared Imaging Spectrometer (VNIS) collected their spectral data at close range. In this work, we focus on the visible/near‐infrared image cubes captured by the VNIS. Simple classification was performed using the K‐means algorithm based on the 750/900 nm spectral ratios to highlight the surface material variations. In the case of narrow measurements of phase angle, the classification results were not significantly affected by viewing geometry. Varying degrees of dust coverage on the rock surfaces were revealed, which may be attributed to ejecta deposition and dust electrostatic levitation. The spectral shapes of the less dust‐covered surfaces indicated that these rocks are dominated by mafic materials, suggesting they may not originate from the lunar upper crust. The influence of dust coverage on spectral measurement of rocks was also confirmed, which significantly attenuates the absorption depths.