First settlers on the Moon and Mars could build their houses out of potatoes and salt
First, it was mushrooms. Now potatoes are the latest foodstuff paving the way for the houses of the future.
Scientists from the University of Manchester have created a new building material dubbed ‘StarCrete’ that with the help of potato starch - and a pinch of salt - could help build extraterrestrial dwellings.
It comes after the American architecture firm Red House announced in February that it was working with NASA and the Massachusetts Institute of Technology (MIT) to build homes made of fungus and dehydrated algae in space.
Ensuring a sustained human presence on the lunar and Martian surfaces demands solving several puzzles, among them figuring out how to build robust and sustainable habitats that provide a shielding layer against radiation, as well as finding high-strength materials from in situ resources.
Ideally, the production of such materials would also be achieved through relatively simple, low-energy processes that also support other critical systems, such as eating or breathing.
The University of Manchester team believe one possible solution to the problem could be potato starch which would be bound together with lunar soil.
In their experiments, scientists used ordinary starch with a pinch of salt - magnesium chloride, obtainable from the Martian surface or bizarrely, from the tears of astronauts - to glue and structure martian soil and to produce “a high-strength biocomposite material” that they have named “StarCrete”.
The simulated martial soil was sourced from a company called Exolith Labs which makes high-fidelity regolith simulants - dust, broken rocks, and other related materials - available to researchers and students around the globe.
In an article published in the scientific journal Open Engineering, the scientists said the results provided a material that is twice as strong as ordinary concrete and “perfectly suited” for construction work in extra-terrestrial environments.
“After optimisation, lunar and Martian StarCrete achieved compressive strengths within the domain of high-strength concrete and surpass most other proposed technology solutions despite being a relatively low-energy process,” the study authors said.
Why is potato starch so special?
“Fundamentally, potato starch forms like a sticky mixture and it forms a better glue than the other starches,” Dr Aled Roberts, the lead researcher, told Euronews Next.
It also negates the need to mine or source water.
“The great thing about using potato starch is that we know will be producing some form of starch anyway to feed the astronauts; so we can just produce more of that and use it for construction instead,” said Roberts.
And if scientists can't figure out how to grow potatoes or other food reliably in extraterrestrial settings, “we can just take loads of potato starch and use that as a binder. And the advantage there is that in any case of emergency astronauts can eat it too.”
The team calculates that a sack (25 kg) of dehydrated potatoes (crisps) contains enough starch to produce almost half a tonne of StarCrete, which is equivalent to over 213 brick’s worth of material.
But the real number might be even less. The calculations on their research paper were based on their effort to optimise the materials as strong as possible.
“But actually, if we were going to do it in reality, we wouldn't optimise it to make it as strong as possible; we just need it strong enough for the application which is much less, especially, when you consider this lower gravity on the Moon and Mars,” Roberts said.
The official potato starch-building material ratio is pending, as “NASA isn't sure on how thick they're going to need to make the walls and ceilings just yet because it depends on how much radiation you're willing to tolerate,” he explained.
The research builds on previous work that used astronauts’ blood and urine as a binding agent, which was ultimately determined as “not feasible”.
“The number one priority will be keeping the crew safe, healthy and happy. And if we happen to tax them for their blood plasma, it's going to put their health and well-being at risk,” Roberts said.
However, the blood and urine option could one say save some lives, Roberts believes.
“If in the case of a disaster, in an emergency situation, someone needs to make some pretty strong material quickly then knowing that you can use plasma is useful, knowledge is never in itself a bad thing,” he said.
Is potato starch really a tangible idea for building extraterrestrial habitats?
“I think it's got a good chance, but there's still a long way to go before we actually start building habitats on the Moon and Mars,” Roberts said.
So by that time, we'll probably have lots of other discoveries… someone's probably going to come up with a better idea and innovate. And that's just kind of how it always, always works”.
Roberts' start-up DeakinBio will continue on the lookout for other plant-based binders to build houses on Mars and the Moon, as well as explore “some other crazy ideas just to see what comes from it”.
But for now, they are also studying how to apply their technology on Earth to create clean, sustainable alternatives to concrete and ceramic tiles.