Iterative Subsurface Matrix Excavation: Active Diametral Shoring and Phase-Focused Detonation Dynamics in Lunar Regolith Frameworks

The development of permanent civil infrastructure on the Moon is severely restricted by the limitations of traditional terrestrial subsurface excavation methodologies when subjected to extreme exospheric conditions. Conventional mechanical excavation architectures rely on gravity-dependent downward forces to generate sufficient Weight-on-Bit (WoB) to shear, cut, or crush target geological formations. In a fractional gravitational field of 1/6 g, generating these required reaction forces on the Moon necessitates the deployment of massively stabilized surface platforms, which presents a prohibitive payload launch mass bottleneck. The structural mass of these mechanical frames is completely bypassed by the frictionless, chemically driven Iterative Subsurface Matrix Excavation (ISME) detonation sequence. This framework introduces a mechanical-first paradigm that replaces continuous rotational mechanical cutting with discrete, highly focused directional detonations. To align this model with mainstream continuum mechanics, the high-density energy field of the detonation is formulated as a localized, structural modification of the space-time stress-energy tensor : where the intense, localized energy density () and pressure () are modeled as retaining a functional, structural mass component within the bounded vacuum lattice of the target rock, such as anorthosite or basaltic bedrock. Rather than dissipating spherically as observed in unconfined atmospheric environments, the high-density detonation wave front couples directly with the solid medium. This interaction transforms the explosive energy into directional, high-frequency kinetic vectors that initiate fracture networks along a pre-determined matrix grid, completely bypassing the need for heavy, surface-stabilized mechanical percussive machinery. Furthermore, quantum mechanical first-principles reveal that the absence of ambient water and atmospheric gases preserves pristine, unsaturated chemical bonds on fractured regolith surfaces. This highly reactive molecular state, combined with continuous exospheric sputtering from solar wind ions (, ), yields a highly cohesive and abrasive subsurface target.1 The directional detonation paradigm exploits these pristine lattice structures by utilizing the natural stress-wave propagation characteristics of the rock to initiate clean crack networks. The mineralogical phase dynamics under these conditions dictate the mechanical efficiency of the stress-wave coupling. High thermal gradients also compromise conventional drilling metals; for example, during the total solar eclipse on March 14, 2025, surface temperatures at Mare Crisium near Mons Latreille plummeted from 40°C to -170°C within hours, exposing drilling equipment to severe thermal contraction and stress-induced fracturing