What’s in News:

• Researchers from the Indian Space Research Organisation (ISRO) and the Indian Institute of Science (IISc) have developed a way to make bricks from Martian soil with the help of bacteria and urea.
• These ‘space bricks’ can be used to construct building-like structures on Mars that could facilitate human settlement on Mars.

The process used by the researchers

• The team first made the slurry by mixing Martian soil with guar gum, a bacterium called Sporosarcina pasteurii, urea and nickel chloride (NiCl 2). 
• This slurry can be poured into moulds of any desired shape, and over a few days the bacteria convert the urea into crystals of calcium carbonate. 
• These crystals, along with biopolymers secreted by the microbes, act as cement holding the soil particles together.

Advantages of this method

• This method ensures that the bricks are less porous, which was a problem with other methods used to make Martian bricks. The bacteria seep deep into the pore spaces, using their own proteins to bind the particles together, decreasing porosity and leading to stronger bricks.
• The current slurry-casting method can also produce bricks of complex shapes.

Challenges faced by the researchers

• The composition of Martian soil has a lot of iron that causes toxicity to organisms and it doesnt let bacteria grow at all. Adding nickel chloride was the key step in making the soil hospitable to the bacteria.
• The Martian atmosphere is a hundred times thinner than that of Earth’s, and contains over 95% carbon dioxide, which may significantly affect bacterial growth.

References:

1. https://www.thehindu.com/news/national/karnataka/isro-iisc-researchers-develop-way-to-make-bricks-from-martian-soil/article65338661.ece
2. https://www.newindianexpress.com/cities/bengaluru/2022/apr/20/want-to-build-a-house-on-mars-iisc-and-isro-researchers-now-have-bricks-just-for-you-2444379.html