The UK’s Monolite supplied the D-Shape printer for ESA's 3D-printed lunar base study, with a mobile printing array of nozzles on a 6 m frame to spray a binding solution onto a sand-like building material. 3D ‘printouts’ are built up layer by layer – the company more typically uses its printer to create sculptures and is working on artificial coral reefs to help preserve beaches from energetic sea waves. First the simulated lunar material with magnesium oxide – turning it into ‘paper’ to print with. Then for structural ‘ink’ a binding salt is applied which converts material to a stone-like solid.