"In the case of burns, for instance, brand new skin could be bioprinted instead of being grafted from elsewhere on the astronaut's body, doing secondary damage that may not heal easily in the orbital environment," said Tommaso Ghidini, head of the division at the European Space Agency that oversees the project, in a statement.

Scientists were faced with the unique challenges of creating a technique that would still work in zero gravity. So, the team invented a method of 3D printing that would work while upside down. They thickened human blood plasma, which is used to bioprint skin cells, with plant material so it could work in altered gravity. To 3D print bones, they added calcium phosphate bone cement to printed human stem cells. The calcium phosphate works as a structure-supporting material, and is absorbed by the body as the bone grows.

The samples are just the first steps in a long journey to make this type of 3D printing ready for space. A self-contained spacecraft can only hold so much. The project is looking into what kind of onboard facilities would be needed, such as surgical rooms and equipment, for astronauts to perform the 3D bioprinting on their own. For a look at how the team at ESA were able to create the bioprinted skin and bone, take a look at the videos below.