Space lovers who The dream of one day colonizing Mars has to face the reality of the planet’s limited natural resources, especially when it comes to building materials. A team of scientists from the Singapore University of Technology and Design discovered that the organic polymer chitin, found in the exoskeleton of insects and crustaceans, can be easily converted into a viable building material for basic tools and habitats using simple chemistry. This would require minimal energy consumption and no special equipment to be transported. The scientists described their experiments in an article recently published in the journal Plus one.
“The technology was originally developed to create circular ecosystems in urban environments,” said co-author Javier Fernandez. “However, because of its efficiency, it is also the most efficient and scalable method for producing materials in a closed artificial ecosystem in the extremely scarce environment of a lifeless planet or satellite.”
As we previously reported, NASA has announced an ambitious plan to bring American astronauts back to the moon and establish a permanent base there to eventually place astronauts on Mars. Materials science will be vital to the success of the Artemis Moon program, especially when it comes to the materials needed to build a viable moon (or Martian) base. For example, concrete requires a significant amount of added water to be used on site, and there is a marked water shortage on both the Moon and Mars. And the transport costs would be prohibitively high. NASA estimates that it would cost around $ 10,000 to transport just 1 pound of material into orbit.
Therefore, great attention has been paid to the possibility of using existing materials on the moon itself to build a moon base. Previous proposals called for 3D printing with Sorel cement, which requires significant amounts of chemicals and water (consumables), and a stone-like material that requires both water and phosphoric acid as a liquid binder. And back in March, an article by an international team of scientists suggested that astronauts building a base on the moon could use the urea in their urine as a plasticizer to turn lunar soil into a concrete-like building material.
As on the moon, any plan to build a habitable base on Mars must employ manufacturing technologies that utilize the regolith of the red planet. However, the authors of the current paper suggest that most terrestrial manufacturing strategies that could fit into the bill typically require specialized equipment and a lot of energy. “However, nature presents successful strategies of life that adapt to harsh environments,” the authors wrote. “In biological organisms, rigid structures are formed in that inorganic fillers with low energy costs (e.g. calcium carbonate) come from the environment and are incorporated into an organic matrix (e.g. chitin) that is produced at relatively high metabolic costs.”
Fernandez and colleagues claim that chitin is likely part of a planned artificial ecosystem because it is so abundant in nature. For example, it is the main component of fish scales and fungal cell walls, as well as the exoskeleton of crustaceans and insects. In fact, insects have already been selected as a key source of protein for a possible Mars base. And since the chitin component of insects has limited nutritional value to humans, extraction into building materials “cannot hinder or compete with the food supply,” the authors write. “Rather, it’s a by-product of it.”
For their experiments, the researchers relied on fairly simple chemistry. They took chitosan extracted from shrimp, dissolved it in acetic acid – a common by-product of aerobic and anaerobic fermentation – and combined it with a mineral equivalent to Martian soil to make their building material, which contains chitin. They tested its properties by making various objects out of it, in particular a function key, which they tested by tightening a hexagonal screw. While it was recognized that this was unlikely to replace metallic tools for certain critical space applications, it was found to be robust enough to maintain sufficient torque for small daily tasks.