Walking on the moon remains a potent ambition for many people who want to explore the its mineral resources, observe the Earth, monitor weather conditions and even carry out astronomical observation. But Italian engineer Enrico Dini does more than dream about the moon. He aims to use a 3D printer to build moon bases for the European Space Agency. To do so he has created D-Shape, the largest 3D printer in the world. It makes a sort of instant sandstone that Dini says is more durable than concrete and does not require steel reinforcements: "The principle of how the 3D printer works is extremely simple. It's a machine that releases layers of sand, very thin layers, 5mm thick, and sprays a binder, that is a sort of salt water, cementing the sand only in the shapes of a section of the object. The idea is to build a full lunar base, designed by architects Foster & Partners, protected by a honeycomb wall constructed using Enrico Dini's technology. It would be made using lunar sand to avoid the need to transport building materials to the moon, which would be unfeasibly difficult and expensive. Xavier De Kestelier, the co-head of Foster & Partners specialist modelling group, explained how it would work: "You would have a solid hard shell, a cylindrical element, that you're bringing from Earth, and out of that you can have an inflatable. And what we'd do, on the top of that inflatable, which is a kind of support structure, we'd have small robots that will print all around that inflatable. And that would give you your shell, your structure, to protect you from solar radiation, gamma radiation and also meteorite impacts. And if it works on the Moon, why not on Mars? More about: European Space Agency, Mars, Moon, Space engineering, Space exploration