Space travel requires us to be able to make use of materials which are present on extraterrestrial surfaces. Until now, much of the research into 3D printing objects from extraterrestrial materials has been done with hard materials. According to 3DPrint.com, however, two teams have decided to take an approach similar to 3D painting, a process that works with more malleable materials to extrude objects.
What are the teams printing with?
The teams have both decided to use a mixture of nearly 90% simulated Regolith from volcanic soil, which NASA has deemed a close alternative to martian and lunar regolith. The mixture also contains a surfactant, plasticizer, an evaporant, and polylactide-co-glycolide (PLGA), a biopolymer which acts as an elastomeric binder, allowing the products to retain their original shape even after being deformed.
These normally rough, harsh materials can be exposed to these agents to produce a malleable compound which is used to print bricks, cylinders, and even tools for use in foreign environments. While traditional methods produced brittle finished items, the processes these teams used produced objects capable of being compressed and retaining their shape without cracking.
How does it work?
The additives blend into a mixture comprised of roughly 85% simulated regolith to create a semi-solid which can print with a variety of nozzle sizes and extrusion pressures, making it a highly adaptable compound. Beyond nozzle and pressure adaptability, the material can print into divots in the previously printed layer, so long as the first layer adhered properly.
The materials had issues adhering initially, so the Northwestern University team tested sandpaper and silicon carbide paper–both saw successful adhesion at the first layer of printing. The finished products were also easy to remove upon completion and had little or no time between print completion and handling.
How effective is it?
The processes resulted in parts with flexibility and reasonable tensile strength. The parts were subjected to intense flexing and showed no cracks under pressure of testing. While the material was generated from Hawaiian volcanic soil, it was deemed by NASA to be an effective mimic for the lunar and martian regolith properties needed for testing.
The processes succeeded in creating parts which had desirable properties while also remaining materially efficient. The binding agents and polymers are often found in urine and other biological waste, allowing for every resource to be reused and recycled.
What does this mean for expansion beyond Earth?
While the stand-in material in the experiments was not true martian or lunar regolith, NASA determined that it was close enough of an analog to begin testing. The final tests will have to be with true regolith from the respective surfaces, but for now, it seems completely feasible to visit other planets and print livable structures from preexisting resources.
RoboHub has reported projects involving inflatable domes surrounded by these 3D printed structures for dwellings on other planets.
3D printing in space was the first hurdle, printing with extraterrestrial resources was next. As humans continue to expand their understanding of the space around them, they will likely expand their ability to inhabit the surrounding areas. A blockchain startup has emerged with the purpose of creating Mars specific cryptocurrency.
3D printing is far from a new science, but the scope of its applications has expended time and again over recent years. First we moved 3D printing into space and now we expand into using extraterrestrial materials for 3D printing applications. The time draws near when we will move out and expand into space.