Slava G. Turyshev

This paper presents a rigorous analytical framework for quantitatively evaluating space-based laser power beaming from lunar-orbiting spacecraft to surface receivers, addressing the critical need for continuous, high-density energy to sustain lunar exploration and habitation. The framework integrates physics-based models of spacecraft photovoltaic generation, precise orbital geometries, time-dependent link availability and slant-range variations, coherent beam propagation (including transmitter aperture diameter, beam quality factor, path losses, and pointing jitter), and photonic-to-electrical conversion at the lunar surface. Particular emphasis is placed on phased-array transmitter systems, whose large effective apertures significantly reduce beam divergence relative to single-aperture designs, resulting in orders-of-magnitude increases in delivered surface power under equivalent orbital and power conditions. Parametric sensitivity analyses and illustrative numerical simulations demonstrate how phased-array architectures improve power density and end-to-end efficiency at operational lunar distances. The study also examines advanced orbital configurations (e.g., Near-Rectilinear Halo Orbits, Earth-Moon Lagrange points), real-time adaptive beam steering and wavefront control, optimized receiver geometries, and thermal/dust mitigation strategies. The results establish a clear pathway toward scalable, efficient laser power beaming infrastructures capable of overcoming lunar-specific challenges - including prolonged darkness and permanently shadowed regions - and enabling sustained robotic and crewed surface operations.