Lunar 3D Concrete Printing: Current Status, Challenges, and Future Prospects

3D Concrete Printing (3DCP) represents a pivotal advancement for establishing sustainable extraterrestrial infrastructure. This review synthesizes recent progress in lunar regolith-based composites, analyzing the interplay between material formulation, processing parameters, and numerical simulation. While challenges such as extreme thermal cycling, vacuum conditions, and resource scarcity necessitate novel material designs, significant strides have been made in optimizing rheology and deposition fidelity. Crucially, the integration of multi-scale modeling, including Discrete Element Method (DEM), Finite Element Method (FEM), and Computational Fluid Dynamics (CFD), has proven essential for predicting structural performance. Looking ahead, the future of lunar construction depends on bridging current gaps through the development of robust, self-sensing, and autonomous printing systems. Realizing durable habitats requires a strategic shift toward interdisciplinary convergence, combining materials science with robotics to create scalable solutions capable of withstanding the harsh lunar environment. This work outlines the pathway toward reliable, formwork-free additive manufacturing essential for future planetary exploration.