Keywords:ISRU, additive manufacturing, 3D printing, direct ink writing, lunar regolith, sintering
This work explores the use of a lunar regolith simulant as feedstock for the direct ink writing additive manufacturing process as an option to enable future lunar in-situ resource utilisation. The feasibility of this approach is demonstrated in a laboratory setting by manufacturing objects with different geometries, using methyl cellulose or sodium alginate as binding agents, water and lunar regolith simulant to create a viscous, printable ‘ink’. A custom three-axis gantry system is used to produce green bodies for subsequent sintering. The sintered objects are characterised using compressive strength measurements and scanning electron microscopy (SEM). It is proposed that the bioorganic compounds used in this work as additives could be produced in situ for a future lunar base through photosynthesis, utilising carbon dioxide exhaled by astronauts together with the available sunlight. Thus, all the components used for the dispersion – additive, water, and regolith – are available in situ. The compressive strength for sintered samples produced with this method was measured to be 2.4 MPa with a standard deviation of 0.2 MPa (n = 4). It is believed, based on the high sample porosity observed during SEM analysis, that the comparatively low mechanical strength of the samples is due to a low sintering temperature, and that the mechanical strength could be increased by optimising the sintering process further.