Researchers at IIT-Madras have tasted success in extracting silicon carbide from (simulated) moon soil — a development that could lead to the making of silicon carbide-based composites for building lunar habitats.
Nithya Srimurugan, a PhD student, and his professor Dr Sathyan Subbiah at the Department of Mechanical Engineering worked on extracting useful materials from lunar regolith.
Lunar regolith is not easy to get — after all, only 382 kg of moon rocks and soil have been brought to the earth, and nobody is going to dispense it freely to every researcher. But, fortunately, there are entities that make simulated lunar soil for research. Srimurugan got some from Space Resource Technologies and Exolith Labs.
Moon has two distinct terrains — the plains, known as maria (plural for mare), and highlands. Each has its own composition and characteristics. Highlands are rich in silicon (among other elements such as aluminium and calcium). These elements exist as oxides — to get the metals you have to drive out the oxygen.
Srimurugan wanted to make silicon carbide — the light and strong stuff with which we make abrasives. Silicon carbide is a combination of silicon and carbon. Where do we go for carbon on the moon? The breath exhaled by those living there will be made up of carbon dioxide, but this does not react with anything.
However, at the International Space Station, a boarding-cum-research lab that orbits 400 km above the earth, the Sabatier process is used to convert the carbon dioxide exhaled by the astronauts into methane and water by adding hydrogen from electrolysers.
At the ISS, the methane is vented into space, but it is precious for Srimurugan. When he combined the highland regolith simulant and with methane at high temperature, he was able to get silicon carbide.
In a chat with Quantum, Srimurugan stressed that more research is needed to produce bigger quantities of silicon carbide from lunar regolith, en route to making composites for building habitats on the moon. But his work, which is currently under review, marks a good beginning.
