Planning for Sun-Synchronous Lunar Polar Roving

• Main Author: Nathan D. Otten
• Format: Thesis
• Language: unknown
• Published: 2018
• Subjects: Adaptive Agents and Intelligent Robotics; Robotics Institute; South Pole; South pole
• Online Access: https://doi.org/10.1184/r1/6721082.v1; https://figshare.com/articles/Planning_for_Sun-Synchronous_Lunar_Polar_Roving/6721082

Lunar polar resources can accelerate deep space exploration by resupplying missions with oxygen, water, and propellent. Before lunar resupply can be established, the distribution and concentration of water ice and other volatiles abundant at the poles of the Moon must be verified and mapped. The need for aordable, scalable exploration of the lunar poles motivates the deployment of solar-powered rovers and planning strategies that sustain robotic missions beyond a single two-week period of lunar daylight. Reliance on solar power at the lunar poles gives rise to significant challenges| and opportunities|for individual rovers to achieve multi-lunar-day longevity. Solarpowered rovers require persistent sunlight for power and heat, lest they succumb to the cryogenic temperatures of lunar night. Although constrained by thermal conditions and available power, opportunistic polar rovers can maintain warmth and ample solar power for several months by following sun-synchronous routes. Strategic, informed route planning that exploits polar lighting enables sustained lunar polar roving and resource prospecting not possible by other means. This research develops polar roving strategies and applies global path planning methods to generate spatiotemporal routes that provide multiple lunar days of uninterrupted sunlight while satisfying constraints on rover speed, terrain slope, and direct-to-Earth communication. The existence of feasible sun-synchronous routes on the South Pole of the Moon is demonstrated by proof-of-concept examples that last multiple lunar days. These are generated using spatiotemporal predictive models of dynamic surface illumination and Earth view based on ephemeris data and global topographic maps derived from Lunar Orbiter Laser Altimeter data. In addition, this research addresses issues of route robustness. Predictive model uncertainty stemming from topographic measurement error presents substantial risk to rovers dwelling at predicted local peaks of persistent sunlight. This thesis presents a strategy ...