Researchers find a way to build buildings with dirt and urine

The famous Russian Rocket scientist Konstantin Tsiolkovsky once said, “Earth is the cradle of mankind, but you can’t stay in the cradle forever.” Tsiolkovsky is often hailed as one of the fathers of rocketry and astronautics and is remembered for his belief in mankind’s dominance in space, also known as anthropocosmism. His work in the late 19th and early 20th centuries helped shape space exploration decades before mankind first walked on the Moon.

The second half of Tsiolkovsky’s famous quote refers not only to life on Earth, but also to addiction as we venture further into the cosmos. Even today, as the International Space Station orbits overhead at 28,000 kilometers per hour (17,500 miles per hour), these astronauts need constant resupply from the ground to stay alive. Future astronauts on the Moon may only have to wait three days to receive supplies from Earth, but as we move further into space, especially to Mars, this dependency will no doubt become much greater. more tedious, time-consuming and costly. Therefore, if humanity wants to establish a long-term presence in space, we must learn to use the resources we have.

A team of researchers from the Indian Institute of Science (IISc), in collaboration with the Indian Space Research Organization (ISRO), has developed a sustainable method to make bricks from Martian soil, using bacteria and urea. Mammals, including humans, are major producers of urea. Because they secrete urea as the main nitrogenous waste product, they are called ureotelic animals. Urea plays an important role in the metabolism of nitrogen compounds by animals. These so-called “space bricks” can be used to construct building-like structures on Mars that could facilitate human settlement on the Red Planet.

Credit: Nitin Gupta, PhD student, Department of Mechanical Engineering, Indian Institute of Science (IISc)

The manufacturing method of these space bricks has been published in PLOS One. A porridge is first created by mixing Martian soil (simulant) with guar gum, a bacteria called Sporosarcina pasteurii, urea and nickel chloride (NiCl2). This porridge can be poured into molds of any shape, and within days the bacteria convert the urea into crystals of calcium carbonate. These crystals, along with the biopolymers secreted by the microbes, act like the cement that holds the soil particles together. An advantage of this method is the reduced porosity of the bricks, which has been a problem with other methods used to consolidate Martian brick soil.

“Bacteria infiltrate deep into pores, using their own proteins to bind particles together, decreasing porosity and leading to stronger bricks,” says Aloke Kumar, associate professor in the Department of Mechanical Engineering at IISc, l one of the principal authors of the paper.

The group plans to study the effect of Mars’ atmosphere and weak gravity on the strength of space bricks. The Martian atmosphere is 100 times thinner than Earth’s atmosphere and contains over 95% carbon dioxide, which can significantly affect bacterial growth. The researchers built a device called MARS (Martian AtmospheRe Simulator), which consists of a chamber that replicates the atmospheric conditions found on Mars in the laboratory.

Use of in situ resources

The IISc study published in PLOS One is based on a practice known as in-situ resource utilization (ISRU), which refers to the generation of products from local materials or essentially land life. As noted earlier, the further humanity ventures into space, the more important it will be to generate products from local materials, as resupplies from Earth will be tedious, time-consuming and expensive. The European Space Agency is currently working on the ISRU demonstration mission, the objective of which is to show, by 2025, that the production of water or oxygen on the Moon is feasible. NASA’s Lunar Surface Innovation Initiative will also develop and demonstrate technologies to use the Moon’s resources to produce water, fuel and other supplies, as well as capabilities to dig and build structures on the Moon.

ISRU system concept for autonomous robotic excavation and processing of Mars soil to extract water for use in exploration missions. (Credit: NASA)

indian institute of science

The Indian Institute of Science is a renowned public research university for higher education and research in science, engineering, design and management. It is located in Bangalore, in the Indian state of Karnataka. IISc’s Department of Mechanical Engineering conducts research in areas such as biomechanics and medical devices; fluid mechanics and flow physics; Heat and energy transfer systems; manufacturing and materials; Mechanics of Solids and Structures; mechanisms, designs and optimization; micro- and nano-scale processes and devices; Robotics and Autonomous Systems; and Vibration, Acoustics and Control. Nitin Gupta, who is the second author of the study, holds a Ph.D. student in the mechanical engineering department of the IISc whose research focuses on the mechanical and material characterization of bio-consolidates, made up of lunar soil regolith, using techniques such as XRD, micro-CT, SEM, UTM, TGA and high throughput testing.

What will future ISRU studies reveal about how we can live and work in space in the long term? Only time will tell, and that’s why we do science!

This article was originally published on Universe today by LAURENCE TOGNETTI. Read the original article here.

Marjorie N. McClure