3D printed continuous basalt-fibre/PA12 composites under space environment: a morphological and chemical assessment

Establishing permanent infrastructures on the Moon will require extensive use of autonomous additive manufacturing processes. In an in-situ resource utilization perspective (ISRU), lunar regolith has already been processed into fibres which can further be embedded into a polymer matrix. Such a composite material, made of polyamide 12 reinforced by continuous basalt fibres (referred to as PA12-basalt) is here manufactured via continuous filament fabrication (CFF). The 3D-printed parts are then exposed to three accelerated ageing and space conditions: hygrothermal ageing, ultra-violet (UV) irradiation and thermal cycling in vacuum (TVAC). The temperature conditions of the tests, most of which exceeding the glass transition temperature of PA12, act as an annealing process on the parts. Simultaneously, significant changes at the polymer chain level when exposed to hygrothermal ageing or UV light, however without drastically influencing the optical properties nor the surface morphology (with the noticeable exception of the erosion reported for samples exposed to atomic oxygen). Overall, under the tested conditions, PA12-basalt appears as a suitable candidate material for 3D-printed structures both in low-Earth orbit and on the Moon.