We are developing algorithms to plan paths in which rovers can drive safely in environments where the illumination and direct-to-Earth visibility conditions change as time passes. Using digital elevation models (DEMs) of the Moon and ephemerides of the Sun, Moon, and Earth to simulate what the environmental conditions will be at any desired point in time. We utilize the results to determine evaluation functions according to the requirements of the mission and solve the problem of finding the optimal path.

This animation displays the environmental conditions in lunar polar regions by color, on which it plots out a path in magenta.

White area: Illumination and direct-to-Earth visibility conditions are good, and slopes are gentle
Blue area: Only direct-to-Earth visibility conditions are poor
Yellow area: Only illumination conditions are poor
Red area: Illumination and direct-to-Earth visibility conditions are both poor
Black area: Slopes are too steep to traverse

Published under the title “Spatio-Temporal Path Planning for Lunar Polar Exploration with Robustness against Schedule Delay” on pages 304-311 of Transactions of the Japan Society for Aeronautical and Space Sciences Volume 64, Issue 6 (2021).（https://doi.org/10.2322/tjsass.64.304）