When will humans land on Mars? A recent report suggested 2038 as the most likely launch year for a crewed Mars mission—largely because that’s when Earth and Mars are closest in the late-2030s—with 2048 classed as the date for a “late launch.”
Human settlement on the red planet could come much later, but if and when it happens there will be huge challenges to overcome. Where will future Martians live? What will they eat? Both of those questions are beginning to be investigated by scientists—and some of the early answers are a bit strange.
Two recent research papers have highlighted the possible importance of human waste and kombucha in building and sustaining a colony on the red planet.
Smelly ‘space bricks’ on Mars
The first whiff of a plan to build settlements on Mars comes from a study published in the journal PLOS One that reveals bacteria and urea from astronauts’ urine could be used to make “space bricks.”
Researchers from the Indian Institute of Science (IISc), in collaboration with the Indian Space Research Organisation (ISRO), think that the recipe will require Martian soil, guar gum, a bacterium called Sporosarcina pasteurii, urea and nickel chloride (NiCl2). The resulting space slurry could then be poured into moulds of any shape with the bacteria converting the urea into crystals of calcium carbonate. The result would be a kind of cement to hold the soil particles together—and bricks.
“The bacteria seep deep into the pore spaces, using their own proteins to bind the particles together, decreasing porosity and leading to stronger bricks,” said Aloke Kumar, Associate Professor in the Department of Mechanical Engineering at IISc, one of the senior authors of the paper.
Adding nickel chloride is key because without it the iron-rich Martian soil is toxic to the bacteria.
Next up is a project to test if these “space bricks” will hold up to the effects of Mars’ thin atmosphere and low gravity, using a chamber that reproduces in the lab the atmospheric conditions found on Mars.
Mushroom tea on Mars
A second breakthrough into sustaining human life on Mars comes from kombucha, whose survival in Mars-like conditions was studied by a team of scientists in Germany and Brazil as part of the Biology and Mars Experiment (BIOMEX) project.
Sometimes called tea fungus or mushroom tea, kombucha is produced by fermenting sugared tea using kombucha cultures, a symbiotic culture of bacteria and yeast.
The latest paper, published this month in Frontiers in Microbiology, reveals that the popular black or green tea’s fermentation process allows a cellulose-producing bacterial species to survive.
That’s important because cellulose—which is probably responsible for the bacteria surviving in extraterrestrial conditions—could be used on Mars as a preservative, a food additive and a fibre supplement in extraterrestrial settlements.
Cellulose-based membranes or films could also be useful for producing various consumer goods.
“We found that the simulated Martian environment drastically disrupted the microbial ecology of kombucha cultures,” said Bertram Brenig, head of the University of Göttingen’s Institute of Veterinary Medicine. “However, we were surprised to discover that the cellulose-producing bacteria of the genus Komagataeibacter survived.”
The same team previously sent kombucha cultures to the International Space Station (ISS) in 2014.
It’s useful information for future Mars colonists, but it also suggests that bacterial cellulose could be a biomarker for extraterrestrial life.
If humans are ever to settle Mars then a lot of science has to be done in advance. “I’m so excited that many researchers across the world are thinking about colonising other planets,” said Kumar on the “space bricks” team. “It may not happen quickly, but people are actively working on it.”
Wishing you clear skies and wide eyes.