Analyze This: Insect shells could help builders on Mars
People will have to be resourceful to find ways to create Martian dwellings and tools
This Martian figurine and block have been molded from a material that could be used for building on the Red Planet. The material is made of a mock Martian soil with a bit of chitin. That chitin is found in fungi and the shells of insects and crustaceans.
Javier G. Fernandez, 2020 (CC-BY)
When people make it to Mars, they’ll need somewhere to stay. There aren’t many building materials available on the Red Planet. But a compound found in the shells of insects may help. That’s the finding of a new study.
Because Mars is so far away and bringing supplies from Earth so costly, astronauts will need to make a lot of what they’ll need. “The problem is that you need to do it in a place that is the opposite of Earth,” explains Javier Fernandez. A materials scientist, he works at the Singapore University of Technology and Design. He was part of a team that developed a new material that may work to create buildings on Mars.
Earth has plenty of building materials. There’s abundant stone, wood, metals and more. But on the Red Planet, Fernandez says, “The only thing that you have is the soil, the sand, that covers Mars.” Astronauts also will have whatever wastes they create. The team’s new material uses a mix of Martian soil and a compound found in fungi and the shells of crustaceans and insects. Called a composite (Kum-PAAS-it), this material mix could offer one way to use up the discarded shells of insects that may be grown as food on Mars.
To make their composite, the researchers developed a simple process. First, it removes and modifies a compound, called chitin (KY-tin), from shrimp cells. The process also would work for the chitin in insect shells. Then, the scientists mixed that material with regolith. It’s a rocky mixture that imitates Martian soil. The composite was similar to concrete and brick in strength and in density (or weight per volume). With a mold to shape their composite, the scientists made a working wrench. They also 3-D printed a small model of a Martian habitat.
The researchers tested different recipes for their building material. Those recipes differed in how much chitin and regolith were used. To determine how well these blends would work for building, the scientists tested the materials’ strength and resistance to bending.
Materials that use waste and plentiful resources can help tackle big challenges, Fernandez says. And this composite could make it easier to colonize Mars.
Evaluating recipes
After a chemical treatment that makes it easier to use, chitin becomes “chitosan.” Researchers mixed it with an imitation Martian soil, called “regolith,” in varying ratios (plotted on the x-axis). They measured the properties of these mixtures, called composites. White bars (strength) show how much stress a composite can take before bending. Dark bars (bending resistance) quantify composite’s resistance to bending.
Data Dive:
- The researchers measured the stress a material can take before it bends and its resistance to bending. Why do you think they considered these two qualities when evaluating their composites?
- Look at how the light and dark bars change as the mixture contains more regolith (increasing from left to right on the x-axis). How does the mixture change with increasing amounts of regolith?
- Which ratio of chitosan to regolith is the best for building? Why?
- Which is the worst? Why?
- Think about some common materials used to build: stone, brick, concrete and metal. What other properties might the researchers want to think about in engineering their building materials?
