The Production Population of Impact Craters in the Chang’E-6 Landing Mare

Abstract

The Chang’E-6 mission accomplished the first sample return from the lunar farside. Earlier crater population measurements estimated the model age of the landing mare to range from the Eratosthenian to Late Imbrian, both of which are underrepresented by earlier returned samples. Establishing a new calibration point for lunar impact flux based on isotopic ages of the samples is promising, but the representative crater density for the landing mare (i.e., spatial density of craters with D ≥ 1 km; N (1)) is equally important for this purpose, which lacks good constraints. After excluding the effects of background secondaries, crater equilibrium, and observational uncertainties on crater statistics, this work extracts production populations in different diameter ranges (∼200 m–2 km) from multiple subareas of the landing mare. Cross-validation of the production populations verifies that N (1) derived from direct measurements of craters with D ≥ 1 km in sketched areas are reliable, which is (2.01 ± 0.90) × 10−3 and (6.05 ± 2.71) × 10−3 km2 for the western and eastern mare, respectively.