Sending materials into space is expensive, so the more astronauts can make on-site, the better. Engineers at Washington State University (WSU) have now demonstrated how crushed Martian rock could be mixed with a titanium alloy to make 3D-printable building materials.
For the first astronauts who will spend long periods of time on the Moon or Mars, it’s not really an option to just duck down to the shops when you need building supplies or tools. Most of those materials will need to be sent from Earth at great expense. Ideally, astronauts will be able to make use of the resources around them – even if that’s mostly just rock and dirt.
To that end, scientists have been experimenting with ways to make habitats, building materials, tools, parts and other things directly out of regolith, the rocky “soil” that covers the lunar and Martian surfaces. That could include making the desired shapes using 3D printers, high-powered lasers or concentrated sunlight to melt the material, or compressing it into bricks.
For the new study, the WSU researchers tested how Martian dust would work when mixed with a titanium alloy that’s often used in space exploration because it’s strong, lightweight and heat-resistant. Because they obviously can’t get their hands on the real thing, they used an artificial substance designed to mimic the Red Planet regolith.
A high-powered laser heated the mixed materials to temperatures over 2,000 °C (3,632 °F) to melt them. The team then formed this molten fluid into components of different shapes and sizes, and cooled it into a kind of ceramic material. After it had cooled down, they tested its strength and durability.
The team added different amounts of regolith – 5, 10 and 100% by weight (wt%) – to the mix, and found that the resulting materials performed differently. Perhaps surprisingly, 5% turned out to be the optimal amount, as it cooled without cracking or bubbling and was found to perform better than the titanium alloy alone, boasting more than twice the hardness.
The material made of 100% regolith cracked as it cooled, and wore out the fastest in durability tests, meaning it wouldn’t be suitable as a building material. But the team says that it could still function as a coating against radiation.
Of course, there’s still plenty of room for improvement, but the team says this proof of concept study shows that the idea could work. Further refinement could be done by experimenting with different materials and techniques.
“This establishes that it is possible, and maybe we should think in this direction because it’s not just making plastic parts which are weak but metal-ceramic composite parts which are strong and can be used for any kind of structural parts,” said Amit Bandyopadhyay, corresponding author of the study.
The research was published in the International Journal of Applied Ceramic Technology. The team describes the work in the video below.
Source: Washington State University
