Population of degrading small impact craters in the Chang'E-4 landing
area using decent and ground images
Abstract
Chang’E-4, the first soft landing mission on the far side of the Moon,
provided high-resolution close-range images up to 2.3 cm/pixel,
especially suitable for the study of the degradation in the population
of small-sized impact craters around the landing site. This paper
presents a preliminary analysis of the population degradation mechanism
of the small-sized impact craters. From mosaicked descent camera image,
6316 impact craters in the landing area were extracted, identified, and
classified into four types according to their morphology: complete,
slightly degraded, moderately degraded, and severely degraded craters.
In-situ verification using the lander topographic camera image supported
the crater degradation analysis around the landing site. The small-sized
impact crater population equilibrium analysis was also carried out. Over
99% of the impact craters in the study area are in degradation, which
suggesting the area is severely degraded. Our results suggest that
similar to the findings for impact crater populations above the meter
scale, the size of meter to centimeter scale impact craters is also
strongly correlated with degradation, with smaller impact craters being
more likely to degrade. Images from topographic cameras also confirm the
severe degradation of small-scale craters. The crater populations in
equilibrium of different resolutions areas shows that the cumulative SFD
slope is contrary to previous research results, the smaller the size of
the impact crater, the more difficult for them to achieve impact
equilibrium, which due to secondary craters and the ground resurfacing
caused by neighboring craters’ ejecta.