Fotec, the research arm of the University of Applied Sciences Wiener Neustadt, recently undertook a project for the European Space Agency (ESA) in which they 3D printed miniature buildings out of simulated Martian soil, or regolith. The structures are very miniature, but Fotec chose designs that space travelers are likely to need to fabricate one day, in this case a wall and a conical hut. The soil was mixed with phosporic acid to serve as a binding agent and then extruded in layers, as part of a larger ESA project called "Limited resources manufacturing technologies." Read more at 3DPrint.com: http://3dprint.com/168741/simulated-...il-structures/