Lunar polar illumination based on Chang'E-1 laser altimeter

The illumination condition of the lunar polar regions can be used to analyze the choice of ideal landing sites and to conduct the investigation of possible water ice deposits. The laser altimeter data obtained by 'Chang/E-1' can provide high accuracy digital elevation models (DEM) for polar illumination model. In this study, we establish the mathematical model to study the polar illumination condition, by combining 'Chang' E-1' altimeter data and known parameters related to lunar orbit. The calculation period of illumination rate is 19 years, which is longer than the node precession period (18. 6 years). In this paper, the horizon method is used instead of the ray-tracing method, and the results show: (1) We don't find the areas that receive permanent illumination; (2) There are regions that are in constant darkness; (3) The edge of the craters can be found to be as continuous illumination region in the north summer or the south summer; (4) The Shackleton crater is one of the main targets as landing sites of the lunar rover