A triple-reflector concentrator for lunar exploration

To address the challenges of low solar collection efficiency, large optical aberrations, and unstable energy transmission in lunar exploration and in-situ resource utilization (ISRU), the optimization and dynamic compensation of a triple-reflector solar concentrator are investigated. The concentrator is designed with a primary mirror, a double sided secondary mirror, and a fast steering mirror (FSM). A conjugate-correction method for secondary-mirror aberration compensation is developed, and an effective optical focality (EOF) metric is introduced to balance spherical aberration correction and energy occlusion. Ray-tracing simulations are performed to analyze the evolution of focal-spot energy distribution and aberration patterns. In addition, a coupled dynamic model of the FSM-optical path is established based on the Lagrange formulation to realize precise angular compensation and stable beam control. The proposed system achieves a 204 X concentration ratio and produces a quasi-parallel beam after complete spherical aberration correction. EOF-based optimization improves the effective optical efficiency by approximately 15% compared with conventional dual-reflector systems. With FSM compensation, the tracking angular error is reduced to below 1 μprad, significantly enhancing the stability of long-distance optical energy transmission. The integration of the triple-reflector configuration with FSM-based control achieves coordinated optimization of high-concentration near-field focusing and collimated long-range beam output, while effectively mitigating secondary-mirror obstruction. The findings are of importance for long-term lunar missions, space-based solar power (SBSP), and high-temperature solar thermochemical applications.