ESA Ariadna study 18-9401 investigated basalt-fibre reinforced geopolymer cement made from lunar regolith simulant, funded as a standard study valued at 30k€ and designed to test performance under lunar-like temperature and vacuum conditions. The study examined mechanical strength, radiation shielding, and validation methods including FTIR and SEM, with neutron irradiation experiments used to compare shielding efficiency against sintered and loose regolith.
The technical result is mission-relevant: geopolymer materials showed lower neutron transmission than consolidated or loose regolith, and both reinforced and unreinforced geopolymers outperformed sintered regolith in shielding. The broader design case cited in the study indicates that up to 98% by weight of the material could be in-situ regolith, and a 50 cm shield thickness (99 g/cm2) has been reported as sufficient for a prolonged crewed lunar mission, with 12-month absorbed dose comparable to the annual whole-body radiation worker limit of 5 cSv (5 rem).
Ark action: treat geopolymer regolith shielding as a high-priority construction pathway for habitat walls, shells, and emergency shelters. The team should track basalt-fibre reinforcement, lunar-surface curing under vacuum and thermal cycling, and secondary radiation performance; integrate this material class into habitat mass budgets, radiation models, and ISRU manufacturing roadmaps alongside regolith-only and other additive-construction options.