Geological characterization of Chandrayaan-2 landing site in the southern high latitudes of the Moon

Abstract

ISRO's lunar orbiter-lander-rover mission Chandryaan-2 is scheduled to be launched in the mid of 2019. In this contribution, we have carried out detailed geological characterization of the prime landing site (70.9°S, 22.8°E) of the Chandrayaan-2 lander – “Vikram”. The proposed landing site is located amidst the nearside lunar highlands at high southern latitudes, which is ~350 km north of South Pole Aitken (SPA) basin rim. Topography of the region is generally flat and it is largely confined by craters of varying diameter. The majority (94%) of the landing ellipse (~15 × 8 km) is within the boundary of intercrater plains with a slope <15° and yields a crater retention age of ~3.7−0.04+0.03 Ga. Craters (diameter: ~2.28 m to ~1.13 km) consistent with morphologies varying from fresh to degraded are common within the landing ellipse, though the ellipse center is devoid of craters with significant depth. Analysis of the spectral reflectance data suggests that the landing ellipse is dominantly feldspathic/highland material. The estimated average abundance of elements within the landing ellipse are Fe: 4.2 wt%, Mg: 5.4 wt%, Ca: 10 wt%, and Ti: 0.3 wt%. Results indicate that the surface composition might correspond to FAN dominated material. Based on elemental and spectral analysis results, we envisage possible mixing of highland material with ejecta from multiple craters surrounding the landing ellipse and/or SPA basin, resulting in hybridisation of highland regolith. Together, the results provide a contextual framework for in situ investigations at the proposed landing site.