Comprehensive analysis of Chandrayaan-3 landing site region focussing on morphology, hydration and gravity anomalies

Abstract

In this work, we performed a detailed characterization, of the inter-crater region around the Chandrayaan-3 landing site (LS) using remote sensing data sets obtained from Chandrayaan-2 and other missions. The regolith material at LS is mainly derived from the large craters such as Manzinus, Schomberger craters, etc. and the excavated ejecta of South Pole Aitkin (SPA) basin. The regional slope of the inter-crater plains is found to be <5°, and the local slope around LS to be <3° with minor variations in surrounding topographic relief, which affirms that the LS region is situated in topographic plains. The absolute model age of the LS region was found to be ∼3.94−0.04+0.03 Ga, indicating Nectarian age, and it is consistent with the published geological maps. Moreover, high-resolution images, rock abundance, night-time regolith anomaly temperature, and radar data suggest that the LS region is smooth at centimeter- to decimetre-scale and is devoid of wavelength-scale scatterers such as ground cracks, exposed surface rocks and meter sized boulders. Additionally, the estimated daytime temperature range, hydration abundance, and Water Equivalent Hydrogen near the LS were found to be on average < 290 K, <100 ppm, and ∼ 500 ppm, respectively. The regional crustal structure below the lunar South polar region, covering the LS, shows two prominent sub crustal features which may be related to the lobate scarps, including the one near to LS. The results obtained in this work could set up additional constraints to the observations obtained by instruments on board the Chandrayaan-3 mission. This work also acts as a pre-investment study from the point of view of future sample return missions of ISRO, in which one of the potential landing site could be the inter-crater plain surrounding the Chandrayaan-3 landing site.