A Water-Wall Radiation Shield for a Four-Person Deep-Space Habitat: Attenuation, Mass and Dual-Use Water Budget

This paper presents a computed design for a hydrogen-rich water layer held in wall panels around a cylindrical habitat, so that potable and process water already carried for life support also attenuates galactic cosmic rays and solar particle events. The study is simulated, not measured. Using the stated assumptions in the Methods and the deposited calculation, the headline results are: dose = 217, factor = 3.04, mass = 22670, area = 113.3, spe = 151. All quantities are derived in the accompanying script, which writes the full numerical record to results.json, including inputs, outputs and, where relevant, a parameter sweep. The design is assessed on its computed performance, its mass and power budgets where relevant, and its failure behaviour. Where the computed result is impractical, that outcome is stated plainly in the abstract's terms as well as in the Discussion: the numbers, not the intention, decide whether the principle is attractive at the stated scale. No measurement of a built system is reported, and no flight performance is claimed.