In recent years rapid prototyping (a.k.a. 3D-Printing) technologies gained growing interest in the architecture community for their promise to allow direct construction of buildings with virtually any shape. Some of these technologies have the capability to agglomerate inert materials like sand using a special “ink”. This feature is especially attractive for the space community, for in-situ resources utilization related to manned space exploration. In November 2009 the European Space Agency awarded a General Study Programme contract to an industrial consortium formed by Alta SpA, Monolite Ltd., Foster+Partners and Scuola Superiore Sant‟Anna. The objective of the study is to assess the concept of 3D printing technology as a potential way to build habitat on the Moon using lunar regolith. The consortium merges knowledge in space technology development, 3-D printing at building scale, complex architectural design, and robotics. In particular, Monolite Ltd. holds the rights for the patented D_SHAPE 3D-printing technology which is, among several different rapid prototyping systems, one of those which is closer to enable full scale construction of buildings. In the initial phase of the study, the physical and chemical characteristics of lunar regolith and terrestrial regolith simulants were assessed with respect to the working principles of D_SHAPE. This work also led to the selection of a novel lunar regolith simulant, made using the ashes of the Bolsena volcano in Italy, which almost exactly reproduces the characteristics of the well-known JSC-1A simulant produced in the US. Tests in air and under vacuum were performed in order to demonstrate that the reticulation process takes place using the regolith simulant. The vacuum tests also showed that evaporation or freezing of the ink can be prevented by adopting a proper injection method. In parallel, the general requirements of a Moon outpost were specified, and a preliminary design of the habitat is underway at Foster+Partners. Based on such design, a section of the outpost wall will be selected and manufactured at full scale using the D_SHAPE printer and the selected regolith simulant. Test pieces of the reticulated “concrete” are going to be manufactured in parallel and will be subject to testing of mechanical properties. Finally, based on the results of the study, the guidelines for future spatialization and automation of the printer and for design and 3D printing of the outpost will be drawn. The study conclusion is currently foreseen by Spring 2011.