What will it take to grow food on Mars?

From a science fiction novel to a research reality, Anca Delgado says his new project could change the course of space exploration by human astronauts.

Delgado, assistant professor of environmental engineering at School of Sustainable Engineering and the Built Environment, part of the Ira A. Fulton Schools of Engineering at Arizona State University, recently earned a Emerging frontiers of research and innovationor EFRI grant from national science foundation with co-funding from Nasa. The project seeks to address a critical aspect of travel to distant planets: a sustainable food source.

Anca Delgado graduated from ASU with her doctorate in microbiology. After spending time as a postdoctoral research associate, she became an assistant professor in 2017. Photographer: Monica Williams/ASU

With travel to Mars becoming a possibility over the next decade or two, Delgado says his attention has turned to a major problem facing scientists.

“The soil-like material currently on Mars contains a chemical called perchlorate, which on Earth is a contaminant,” says Delgado, who also holds a professorship in the Swette Center for Environmental Biotechnology in ASUs Biodesign Institute. “The concentration of perchlorate in the soils of Mars is of a higher magnitude than anywhere on Earth. Thus, this chemical can have a substantial negative effect on human health if food is grown and consumed there.

With a background in transforming carbon and chlorine compounds in water and soil using microbial processes, Delgado began to look at the challenges on Mars in a new light. Perchlorate salts that are toxic to humans are chlorine compounds. So, could a technique she had been studying for years be applied in the same way?

“On Earth, microorganisms have no problem taking perchlorate and using it to grow their metabolism and get energy,” Delgado says. “They do what’s called a respiratory reaction that leads to perchlorate sanitization because microorganisms convert that perchlorate into non-toxic byproducts.”

In the case of Mars soil remediation, she says microorganisms would use perchlorate as a resource, producing water and chloride from it. Compared to other food-growing operations, the bioremediation process being tested does not require additional resources that are scarce on Mars or would be a burden to transport there.

“There is always the option of growing food crops hydroponically. But with a significant distance to Mars and the lack of readily available water, we need a different kind of plan,” says Delgado. “If it is possible to grow plants directly in the ground, there are advantages in terms of water use and resources to supply Mars.”

A multi-step process

To begin, Delgado and his team of researchers will work to create a material that replicates the ground cover on the surface of Mars, known as Mars regolith. The entire remediation process will be carried out in a controlled environment similar to a greenhouse. This will allow researchers to control where microorganisms are introduced and track the exit of their byproducts without leaving a lasting effect on Mars’ environment.

“For laboratory testing, there are Martian regolith simulants, which are essentially soil-like inorganic materials with similar mineralogical compositions to those that rovers have detected on Mars,” she says. “We will then add the perchlorate salts to simulate this chemical composition as well.”

Microorganisms will then be added to the Martian regolith simulant to produce the chlorine and water by-products, counteracting the addition of the perchlorates. At this point, Delgado says, the microbial biomass or organic matter of the bacteria that removed the perchlorate will also be left behind — an important step in delivering organic carbon to the soil and a requirement for seed germination.

“This process is the most critical step in research,” she says. “We will test plant growth in regolith simulants where microorganisms have completely or partially removed perchlorate concentrations, and refine the process to convert regolith to plant soil.”

A team of experts

Anca Delgado and student in the laboratory

The project will use a Martian regolith simulant and then perchlorate salts will be added to replicate the chemical composition of flooring found on Mars. Photographer: Monica Williams/ASU

In partnership with Delgado, a team of interdisciplinary researchers from across the country. They understand Andrew Palm, associate professor of ocean engineering and marine science at the Florida Institute of Technology. After the Martian regolith simulant is bioremediated by Delgado’s lab, the soil will be shipped to Palmer’s team to begin the seed germination process, growing a variety of commonly eaten plants.

“The best soils for agriculture on Earth were harvested decades ago, so now we’re trying to cultivate new lands that aren’t really meant for agriculture,” Palmer says. “So while this research focuses specifically on Mars, it has the ability to teach and inspire new farming techniques right here at home.”

Throughout the process, soil samples will also be collected and sent to Tucson, Arizona, where Malak Tfailyassociate professor of environmental science at the University of Arizona, will perform a series of tests to determine if the microorganisms were effective in removing perchlorate and producing soil organic carbon.

“Growing crops on Mars is a difficult task and cannot be done alone. It takes a group of interdisciplinary scientists to address these global and social challenges,” says Tfaily. “Given that the main objective of this project is to grow crops on Mars, we need to understand in depth the organic matter-microbe-plant interactions as well as the social and economic implications of this. Therefore, having expertise in multiple disciplines will allow us to ensure that we are asking the right questions.”

The team also includes Timiebi Aganaba, assistant professor of space and society at the School for the Future of Innovation in Society at ASU with a background in space law and emerging borders.

“As someone who started my career in the space program of a developing country, the question I had to answer every day was, ‘When people are starving, have no electricity or water, why should we do we care about space?”, says Aganaba. “With this NSF project, I finally have a very tangible answer because it is clear that there is a link between the concept of food security and space exploration. “

In this case, interest in growing food in the extreme environments of Mars may spark a conversation about hunger and sustainable food sources in Earth’s extreme environments, especially since hunger affects about 10% of the world’s population.

“The societal implications of everything we do in areas beyond national jurisdiction can no longer be ignored,” says Aganaba. “Advances in science and technology, without the potential to impact large and diverse users, lead to innovations that very few care about or benefit from and have no real value in advancing the common good.”

John Larsson, an associate research professor in ASU’s School of Sustainable Engineering and the Built Environment, will also provide support to advance education and outreach activities related to the project. One postdoctoral researcher, three graduate students and several undergraduate students from the three participating universities will participate in the Mars soil growth mission.

Meanwhile, Delgado says today that we work in a world where the future is now.

“I’ve been a science fiction fan all my life, and I think having been exposed to these stories has opened my mind to the work I do now,” she says. “I’m proud to work at a university like ASU that supports great thinkers and collaboration across disciplines and multiple institutions.”

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