Did the European Space Agency's concept of a 3D-printed moon base seem too outlandish? Don't worry -- the institution has just posted a video (below) that sheds more light on the subject. The colonization mission would revolve around a robotic rover that converts moon dust into a 3D-printed protective layer for an inflatable habitat; after three months, the living space would be safe enough for human settlers. It'd even have windows to provide some natural lighting. This is just a research exercise at present -- it'll likely be years before the ESA can put a base like this on lunar soil. Still, it's clear that the agency's vision of extraterrestrial colonization is more than just a passing fancy.