Optimized Traverse Planning for Future Lunar Polar Prospectors

Introduction: Recent lunar missions provide the planetary science community with vast amounts of new data enabling important insights into the geology and evolution of the Moon on a global scale. Remotely sensed observations of the polar regions reveal the location of persistently illuminated regions and evidence for volatiles captured in cold traps [1-5]. In-situ resource utilization (ISRU) of these volatiles has the potential to transform these regions into fueling stations for future lunar missions as well as create a sustainable architecture for the exploration of the Solar System [6]. However, there are still many questions regarding the chemistry and extent of these cold-trapped resources. To fully characterize the region and ground-truth remote datasets, a future mobile lunar prospector could survey a series of sites to assay resources not only along the surface, but also at shallow depths. Just like previous lunar and Martian rovers, the available power to the rover would be limited by solar panel and/or radioisotope thermoelectric generator (RTG) output. However, unlike previous planetary rovers, the polar prospector would be exposed to intense cold (75-200 K) for extended periods of time due to the extreme illumination environment. Therefore, rover energy management planning will seek to maintain adequate reserves for component heating. Thus, optimal traverse planning that conserves energy (and increases reserves for heating and science instrumentation) will enhance the overall success and longevity of a polar prospector. Modeling the Environment and Energy Usage: To effectively identify optimal traverses, the local topographic and illumination environment need to be characterized. Stereo images collected from the LROC Narrow Angle Camera (NAC) have been co-registered to elevation profiles from the Lunar Orbiter Laser Al-timeter to create merge products that provide accurate and precise elevation models of the polar region [7,8]. In addition, these elevations models along with observed illumination conditions from the Wide Angle Camera (WAC) can be used to characterize the illumination conditions in the region [5,8]. Combining these datasets, we assess the traversability of the terrain and identify optimal traverses and timed sequences. To model the energy usage of the polar prospector along the simulated surface, we use a terramechanics model that simulates the wheel/soil interaction [9-11]. This model enables us to calculate the torque required to move the rover across the lunar surface using the elevation model and the lunar soil trafficability parameters outlined in Carrier et al. [12].