and that means that things can be tried here before actually being attempted on the surface of the moon. and the hope is that one day creating something like this, inhabitable by humans, could be possible. this moon regolith, or simulant, is hoped to be able to create an inhabitable structure that's temperate and can block radiation. well, you have actually the powder in a layer, and then you spray with a nozzle the binder material. the binder material here was an inorganic salt water, and then it comes to a chemical reaction like concrete, if you like, and you build more or less a solid structure, layer by layer. this substance isn't quite perfect, though. so at some point, testing on the real, precious moondust needs to happen. but 3d printing on the moon could go beyond putting a roof over astronauts' heads. we can print polymers,