The European Space Agency wants to put the first 3D printer on the moon, all for the sake of constructing a lunar base.  

“3D printing offers a potential means of facilitating lunar settlement with reduced logistics from Earth,” said Scott Hovland of ESA’s human spaceflight team. “The new possibilities this work opens up can then be considered by international space agencies as part of the current development of a common exploration strategy.”

The "hollow closed structure" is built up layer by layer at a rate of "around 2 meters per hours," said researchers. The "next-generation design should attain 3.5 m per hour, completing an entire building in a week.” 

To create the "paper," or layering materials, "simulated lunar material" is mixed with magnesium oxide, "then for our structural ‘ink’ we apply a binding salt which converts material to a stone-like solid," they explained.  

Time will tell if the ESA is able to pull it off, but preliminary tests have shown positive results. Local materials (i.e., moon rock) are being used to build the structures, a concept that's been done before to create similar structures out of sand, concrete and synthetic moon soil, reports Web Pro News

And lest you think they can't pull it off since all the testing's been done here on Earth, one Italian scientist explained a possible solution: the 3D printer can work in a vacuum so long as there's liquid trapped within the soil; it gets dry over there. 

[via Web Pro News]