RADIATION-STABLE HABITAT ARCHITECTURE: Geometry, Distributed Shielding, and Occupancy Zoning for Mass-Efficient Crew Dose Control

Background Habitat radiation protection is conventionally treated as a local materials and thickness problem: add mass, choose denser materials, bury. This approach treats each compartment in isolation, assumes uniform occupancy, and ignores the available architectural degrees of freedom — 3D geometry, shared shielding mass across compartments, and time-use zoning. No formal theory links these architectural variables to cumulative crew dose budgets under constrained total mass. Gap The Named Binary distinguishing Architecture-Centric Dose Control (ACDC) from Material-Centric Dose Control (MCDC) does not exist in the literature. Habitat design standards do not specify occupancy-weighted dose budgets, shelter sizing and placement criteria, or circulation-shielding requirements. This silence means mass is routinely misallocated, and protective gains available from geometry and zoning are not captured. Approach We formalise habitat primitives (compartments, circulation corridors, storm shelter), define occupancy fractions and shielding mass allocation variables, and derive optimisation objectives under a constrained total shielding mass budget. We present the Strongest Formulation and a pre-registerable Collapse Counter-Scenario (CCS), perform short analytic parametric studies using exponential attenuation approximations, establish structural invariance across three independent engineering domains, and specify a Weil Protocol practitioner review pack. Results For mixed SPE+GCR mission profiles, allocating approximately 15–25% of total shielding mass to a small, rapidly accessible storm shelter — combined with corridor shadowing and activity zoning — reduces the total mass required to meet lifetime dose targets by approximately 25–50% relative to uniform thickness designs. Gains scale with shelter access fraction (fₐccess) and SPE risk. The strategy is most powerful for acute SPE protection; GCR gains are smaller but non-negligible when combined with zoning. fₐccess ≥ 0. 9 is a critical operational constraint. Implications Habitat design standards should mandate occupancy-weighted dose budgets, storm shelter sizing and placement, circulation shadowing, and crew scheduling protocols as co-designed elements. Practitioner review and targeted transport simulations are required to convert the analytic estimates presented here into final numeric design targets.