ESA scientists have been exploring how a future moon base might be built from materials on the lunar surface. Inspired by LEGO building, they have used dust from a meteorite to 3D-print “space bricks” to test the idea.

The idea seems simple. Rather than take building materials all the way to the moon, we could use what is already there to construct a moon base. The surface of the moon is covered with a layer of rock and mineral fragments known as lunar regolith. This material could be used to make space bricks. The only problem was that there’s not much lunar regolith available on Earth to experiment with.

Undeterred, ESA scientists came up with a solution: they made their own version of lunar regolith by grinding up a 4.5-billion-year-old meteorite. The dust from the meteorite formed the basis of a mixture that was then used to 3D print some LEGO-style space bricks.

ESA’s space bricks click together in the same way as regular LEGO bricks but are a bit rougher—and only come in one color—a stylish space gray! The space bricks gave ESA’s space engineers the flexibility to build and test a variety of structures using this new material.