NASA and USQ working on the right formula to help grow crops on Mars

A crewed mission to Mars is no small feat. It would take a minimum of six months and more likely nine months or more to travel to Mars, depending on the complex orbital dynamics between Earth and the red planet. Once the astronauts arrive, any sustained presence will require the ability to produce food, hence the joint research into growing food in space and in extraterrestrial environments.

The challenges of living, let alone growing anything on Mars are complex, and range from the impact of solar radiation to finding water that could be used for both oxygen and fuel. 

The Martian climate is also very hostile to life as we know it - temperatures drop to -63 C, and the air pressure is much lower than that on Earth, so water evaporates very quickly. And that’s even before we consider the impacts of global dust storms that can engulf the entire planet. 

The life of a crop on Mars would be very different from one on Earth. Even if it were to be grown in some kind of habitation dome, there are many things to consider when looking at how plants grow.

Firstly the gravity on Mars is only 38% that of Earth - and plants and trees here use gravity as a way to cement their roots into the soil, to help them build wind stresses. Secondly, plants do not grow in isolation but as part of a complex microbiome, consisting of all sorts of bacteria and fungi mainly around the roots, according to Dr Adam Frew, an ecologist from USQ working on the project. 

“The microbiome of a plant on Earth is made up of all sorts of bacteria and fungi, mainly around the roots, providing vital nutrients,” Dr Frew said.

“But in microgravity, plants may struggle to establish that delicate balance of thousands of microorganisms.”

When one considers all these complex issues, and the sterility of space in general, future crops grown on other planets are going to require Earth-grown microbiomes to be taken out into the Solar system, as humans venture to other worlds.

It is because of this that Dr Frew and his team are looking into producing synthetic or constructed microbiomes that could be seeded onto plants, and working with global space agencies in the process who are interested in the research that he and his team are working on.

“These [synthetic microbiomes] are made of real bacteria and fungi, but the composition has been selected to foster growth and health in a particular plant for a specific environment,” Dr Frew said.

“We’re in discussions with NASA because we’re doing that kind of research for different plants in various environments right here on Earth.

“The theory is you give plants the synthetic microbiome that will enable them to produce more antioxidant chemicals and are therefore healthier to eat and don’t contain harmful bacteria.”

Dr Frew said that one of the big problems is disease. So if you have any thoughts about growing potatoes in your own waste, à la “The Martian” you might want to think again. 

The soil on Mars tends to be very salty, and whilst some kinds of potatoes can grow in the highly salty conditions, it is not clear how safe they would be to eat. It is not just the salt in Mars’ soil that will pose challenges, the soil also contains chemicals called perchlorates and heavy metals such as Lead, arsenic and mercury. More reasons to ensure that the microbiome is understood and has the potential to be recreated on Mars. 

“We think that in space, plants struggle to establish the correct microbiome that they would need,” said Dr Frew.

Studies into plant microbiomes are working towards synthesising hardier plants that could tolerate the extremes of space. Of current interest is a type of sweet potato where they have found a type of fungus that boosts growth. This fungus, found in the roots of the plant, exchanges nutrients with the plant through structures called arbuscules; this exchange provides nutrients but helps the plant defend itself from disease. 

Lauren Huth, Research Facilities Coordinator, Institute for Life Sciences and the Environment, USQ said “ it's really about trying to find which recipe is the best one for growing plants in space”. 

With many thousands of different microbiomes found here on Earth, DNA sequencing projects, like the one currently being conducted by the University of South Queensland, of each plant and its successful microbiome cultures  will help to distinguish what each one does and the potential impact they will have growing crops in space. 

It's vital for future human missions, that go beyond exploration objectives, to resolve these problems before any future settlements and human outposts can start springing up around the Solar system.