基于嫦娥7号探测任务概念设计的月球南极光照条件和电场环境研究

Lunar polar illumination and electrical field environment simulation based on a conceptual design for China's Chang'E-7 mission

月球极区挥发分(包括水冰)是月球探测的重要目标.本文系统地提出了中国嫦娥7号月球南极探测任务的概念设计,包括轨道器、着陆器、巡视器和飞跃器以及中继星.通过轨道器获取的极区高分辨影像可为着陆选址提供参考.巡视器和飞跃器分别对光照区和永久阴影区开展原位探测.所有的数据均通过中继星进行接收并传回地面.考虑到极区特殊的光照条件,我们计算了覆盖沙克尔顿(Shackleton)撞击坑部分区域15 km×15 km范围内2024–2026年的光照率,并分析了潜在着陆区的光照条件、坡度以及距探测目标的距离.考虑到极区因地形遮挡产生的尾迹效应,我们计算了Shackleton撞击坑及其周围区域37 km×27 km范围内的电场环境.发现坑缘周围光照区电势最高不超过2.1 V,而由尾迹效应引起的坑内电势最低可达-500 V.这对以坑底为探测目标的飞跃器来说有必要进行风险评估.

Lunar polar volatiles, such as water ice, are essential lunar exploration objects. The conceptual design for China’s Chang’E-7 lunar exploration mission to the South Pole was proposed. The mission comprises an orbiter, a lander, a rover,a leaper, and a relay satellite. The orbiter can provide high-resolution images to select a suitable landing site. The rover and leaper will be deployed for in-situ exploration in sunlit areas and permanently shadowed regions, respectively. The relay satellite will transmit all data to the ground. We calculated the accumulated illumination, as an engineering condition, within a 15 km×15 km area partially covering the Shackleton crater from January 1, 2024, to December 31,2026. Two potential landing sites-areas SR1 and CR1-were analyzed in detail by comparing their average illumination rate, slope, and distance to the exploration target. Additionally, we simulated the electric field of the Shackleton crater within a 37 km×27 km area, considering the effect of the plasma wake on the electric field in shadowed areas. The results show that the maximum surface potential near the rims is less than 2.1 V, while the minimum surface potential at the bottom of the crater can reach as low as -500 V due to the plasma wake effect. Therefore, a risk assessment is necessary,especially for the exploration of the leaper at the bottom of the Shackleton crater.