Traverse Planning on the Lunar Surface – Benefits from Thermal Modeling

Classic traverse optimization methods focus on energy demands for driving only. The subject of this work is to identify potential for future traverse optimizations in lunar environments by combining thermal modeling with classic optimization methods related to locomotion energy. For this purpose five different traverses are investigated that share the same starting and final point on two sides of a lunar crater. For the simulations presented in this paper, an in-house developed lunar specific thermal preprocessor creates the lunar scenery, the moving sample object, and its traverses in a geometrical and nodal representation. The commercial software package ESATAN-TMS performs the thermal calculations afterwards, starting with ray tracing and finishing with solving the entire nodal network. Rovers can profit from traverse optimization by increasing the mission lifetime or the exploration area because of power savings in the thermal control subsystem. The analysis of all simulated traverses focuses on energetic aspects: energy needed for locomotion, energy needed for thermal control, and possible energy acquired by solar cells. Traverses differ in their distance between two points, the period in shadow and the terrain slope in the same artificial lunar setting. In order to estimate the influence of thermal design, the five traverses were analyzed with three different rover configurations. Results show that energy savings ranging from 32 % to 83 % are possible compared to the shortest traverse, dependent on the rover configuration and the traverse. A longer travel time has to be taken into account for such energy savings.