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Taking a whiz on Mars, it’s a must-do for future Red Planet crews.

But doing so turns out to be good for on-the-spot cultivation of food to help sustain the extraterrestrial experience.

A new study suggests the possibility of using a blend of astronaut urine and Mars regolith to grow cyanobacterium called Synechococcus nidulans.

“We chose to investigate Synechococcus nidulans because it is an extremophile cyanobacterium capable of adapting to extreme environments such [as] the ones taking place on Mars,” explains Alessandro Concas of the Department of Mechanical, Chemical and Materials Engineering at the University of Cagliari in Italy.

Concas is lead author of a paper – “Modeling and experimental assessment of Synechococcus nidulans cultivation using simulated Martian medium and astronauts’ urine” – set to appear in the journal, Acta Astronautica.

Planting life on Mars – future “Martians” set up habitats on the Red Planet.
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Potential food source

Concas and colleagues report that, while efforts are being made to develop novel techniques to cultivate microalgae on Mars, “further research activity is needed to verify the possibility to use microalgae and cyanobacteria as potential food source” in the framework of human expeditions to Mars that rely on in-situ (living off the land) resource utilization (ISRU) technologies.

The research paper explains that, while urine could supply macronutrients such as phosphates and ammonium, “regolith leachate” could provide relevant micronutrients and in particular iron which is known to strongly affect the growth microalgae and cyanobacteria.

Nutritional characteristics

The investigators also make note of the nutritional characteristics of the biomass produced using the selected growth media were investigated for the first time.

“The experimental results have been interpreted by a mathematical model that allows the identification of the set of operating conditions to maximize the biomass, and thus food productivity,” the research team explains.

Starships on Mars.
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The team investigated the capability of the autotrophic strain Chrococcidiopsis sp. CCMEE 029 to tolerate perchlorate salts that are typically found top-side on the Red Planet.

Edible biomass

The results of the research show that the growth of this strain was not affected by Mars-relevant concentrations of Magnesium (Mg) or Calcium (Ca) perchlorate, thus demonstrating that Chrococidiopsis is a good candidate for bio-ISRU contexts on Mars.

According to Concas and collaborators, the results of this activity provide a first assessment on the possibility of growing this strain within a pressurized and heated dome on Mars to produce edible biomass and photosynthetic oxygen.

The growth of microalgae as food for astronauts is one of the main challenges ahead to support humans on Mars.

“The possibility of cultivating the cyanobacterium Synechococcus nidulans in a medium consisting of a mixture of simulated regolith leachate and astronauts’ urine, called Martian Medium, is investigated with the aim of reducing the payload deriving from nutrients to bring from Earth,” the paper notes.