Coherent and Spectral Beam Combining Approaches to Lunar Wireless Power Transmission

Future lunar missions require reliable energy sources to support intensive surface operations and activities including robotic and human exploration, in-situ resource utilization, and scientific activities. Contin uous power availability is a challenge, particularly in permanently shadowed regions and during the lunar night. Space-based wireless power transmission (WPT) can be a transformative technology for enabling sustainable lunar exploration and habitation. This study explores coherent and spectral beam combining (CBC and SBC) approaches for high-power laser-based WPT onboard a satellite constellation designed to provide continuous energy to the lunar surface. The research is part of the all-italian DESIGN project funded by the Italian Space Agency (ASI) in the context of development of projects and scientific experiments for the Moon. Laser-based WPT systems must overcome significant challenges, including working reliably in a space environment, delivery over very long distances, and power scalability. Coherent and spectral beam combining techniques offer promising solutions to enhance power delivery by mitigating diffraction limitations and improving thermal management. CBC achieves high-intensity beams through phase control of multiple laser sources, while SBC increases total transmitted power by combining different wavelength channels. Both methods have been extensively studied for terrestrial applications, but their implementation in space environments requires new design considerations. This first phase of the project focuses on modeling and simulating CBC and SBC architectures in the space context, evaluating their performance in terms of power density, pointing accuracy, and resilience to space-induced perturbations. The study will assess key technological trade-offs, including laser array configurations, phase stabilization mechanisms, and optical receiver designs for maximum energy conversion efficiency on the lunar surface. The findings of this research will inform the development of a prototype system for future experimental validation and contribute to the broader vision of sustainable lunar infrastructure. The outcomes will also have implications for deep-space applications, including planetary exploration and space-based solar power systems.