Spacesuit To Lab Coat, Shubhanshu Shukla's Mars Experiment Takes Off

Group Captain Shubhanshu Shukla's new avatar is ready. Apart from being an astronaut and the first Indian to fly to the International Space Station (ISS), he is also a scientist now.

His first peer-reviewed scientific research paper has been published in the US-based journal PLOS One. This work did not come from experiments aboard the ISS, but from a laboratory on Earth -  the Mechanical Engineering Department at the Indian Institute of Science (IISc), Bengaluru, where Group Captain Shukla is pursuing a Master's degree. This is his life beyond the Indian Space Research Organisation (ISRO).

The study explores a fascinating and futuristic question: can bacteria help humans build structures on Mars, despite the Red Planet's toxic soil?

Scientists, and even entrepreneurs like Elon Musk, are already dreaming of having a permanent human outpost on Mars, the habitable planet nearest to Earth. If that were to happen, it would be near impossible to carry construction material from Earth. So what is the next best alternative?

"The idea is to use what's already there," Shukla says. "If we don't have to carry construction material from Earth, and instead use resources available on Mars, it becomes much easier to support long-term missions."

Toxic Challenge On Mars

Mars may look like a barren red desert, but its soil hides a serious chemical challenge. Several space missions have found perchlorate in Martian regolith, a chlorine-based compound that is toxic to most Earth life. Perchlorate can damage cells, disrupt metabolism, and make survival difficult for microbes.

This poses a problem for scientists exploring the idea of "living construction" on Mars, using bacteria to turn loose Martian soil into solid bricks that could one day form roads, landing pads, or even habitats.

Researchers at IISc decided to investigate whether such bacteria could survive perchlorate-rich soil, and whether construction using these microbes was even possible.

The bacterium 'Sporosarcina pasteurii' collected from Bengaluru soils that aided the process

Bacteria That Build Bricks

The research team focused on a process called microbially induced calcite precipitation, or MICP. In simple terms, certain bacteria can act like microscopic masons. When given nutrients such as urea and calcium, they produce calcium carbonate, a natural cement that binds soil particles together into solid, brick-like blocks.

In earlier studies, IISc scientists had already shown that the soil bacterium Sporosarcina pasteurii could turn simulated or artificial lunar or Martian soil into "space bricks." These experiments also relied on guar gum, a natural adhesive derived from guar beans, which helps the bacteria survive and strengthens the bricks.

For this new study, the researchers used a particularly robust bacterial strain isolated from soil in Bengaluru. Genetic analysis showed it to be closely related to Sporosarcina pasteurii, making it well-suited for biocementation.

Stress Makes Strange Things Happen

When the bacteria were exposed to perchlorate at levels similar to those found on Mars, the results were dramatic. The microbes grew more slowly and showed clear signs of stress. Under the microscope, they changed shape, became rounder, and began clumping together into groups that resembled simple multicellular structures.

The stressed bacteria also released large amounts of a sticky substance known as extracellular matrix, or ECM. Using electron microscopy, the researchers observed that this material formed tiny "microbridges" linking bacterial cells to mineral deposits.

So did a natural cement appear in the toxic soil?

On its own, perchlorate was clearly bad news for the bacteria. Growth dropped, survival rates declined, and the chemical acted as a strong stressor. But when the same bacteria were used to make bricks from simulated Martian soil, something unexpected happened.

Stronger Bricks From Toxic Soil

Synthetic Martian soil used in laboratories overseas usually avoids perchlorate because the chemical is flammable. But to understand its real-world impact, the IISc team carefully added magnesium perchlorate to a commercially available Mars Global Simulant-1, a commonly used Martian soil analogue.

The bricks were made using bacteria, calcium, urea, guar gum, and a small amount of nickel chloride - a catalyst that improves the bacteria's cement-forming enzyme. The result surprised the researchers.

Bricks made in the presence of perchlorate were actually stronger, provided guar gum and nickel were also present. Without guar gum, strong bricks could not be formed at all. With it, perchlorate seemed to enhance the final compressive strength. The scientists believe that stress-induced ECM production and additional mineral precipitates may be acting as extra binding agents, effectively improving the "glue" that holds the soil together.

Thinking Decades Ahead

India does not yet have a declared plan for a permanent human settlement on the Moon or Mars. Yet this research shows that Indian scientists are already thinking far ahead, anticipating the materials, methods, and challenges that future explorers may face decades from now.

Such work fits squarely into the idea of in-situ resource utilisation: building using local materials instead of carrying everything from Earth. This approach could dramatically reduce the cost and complexity of deep-space missions.

It could also solve practical problems. Uneven terrain has already caused problems for lunar landers, and stronger, biologically consolidated surfaces could help stabilise landing sites, rover paths, and launch pads.

An Astronaut's First Scientific Medal

For Gaganyatri Shubhanshu Shukla, the publication marks a deeply symbolic moment. PLOS One is among the world's most respected open-access scientific journals, and getting a first paper accepted there is a significant achievement for any young researcher.

In a sense, this publication is the scientific equivalent of being awarded the Ashoka Chakra, not for bravery in battle or heroics in space, but for rigorous, Earth-bound research that looks to humanity's future beyond Earth.

The study also highlights how astronauts are increasingly becoming scientists in their own right, contributing not just through missions, but through research that shapes those missions long before launch.

Incidentally, Group Captain Shukla did seven basic scientific experiments when he was at the ISS on his 20 day Axiom-4 or Mission Akash Ganga sojourn. These were what his principal investigators asked him to do. Maybe now he will be able to conceive more meaningful micro-gravity experiments as part of India's ambitious Gaganyaan.

"Mars is an alien environment," says Aloke Kumar, Associate Professor of Mechanical Engineering at IISc and the study's corresponding author and Group Captain Shukla's research advisor.

"Understanding how Earth organisms respond to such conditions is a very important scientific question we must answer."

For Scientist Shukla, still very much an Astronaut Shukla, the white lab coat may be just as important as the white space suit. And both, it seems, are pointing him toward Mars. Age is on his side - he's only 40.