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British scientists have shown how astronauts on the moon or Mars could someday extract important metals using bacteria.
In a first-of-its-kind experiment on the International Space Station (ISS), microbes digested the rock to release rare earth elements (REEs).
REEs are incorporated into electronics and alloys in particular.
Researchers tell Nature Communications journal that bio-mining could help make future space exploration more sustainable.
At present, everything needed to survive on another world has to be transported from Earth: from the air an astronaut would breathe to whatever material they might need for repairs.
Transporting all that mass is energy-consuming and expensive, which is why it is now focusing more and more on trying to find ways to use existing resources.
“Wherever you are in space, whether you are building a settlement on asteroids, on the Moon or on Mars, you will need elements to build your civilization,” said the prof. .
“What our BioRock experiment demonstrated is that bio-mining is just one way we could extract useful elements from rocks to support a long-term human presence beyond Earth.”
Prof Cockell’s team developed small bioreactors. These are essentially small boxes containing basalt rock and a community of microbes known to leach metals from minerals.
The reactors were sent to the ISS and placed in a centrifuge where they were spun at different speeds to simulate gravity on Earth and Mars. A third box was allowed to experiment with the entire floating “zero-G” environment of the orbiting laboratory.
The team wanted to find out whether the microorganisms that normally extract REEs from rock here on earth will do the same in space as well.
It wasn’t obvious. Reduced gravity can stress microbes, causing them to behave in different ways. And for two species of bacteria in the BioRock experiment, their willingness to remove metals was very low.
But for an organism called Sphingomonas desiccabilis – was unaffected and happily extracted more REE from basalt, including neodymium, cerium and lanthanum.
“This is the first time in space that anyone has deliberately removed an economically viable element from an extraterrestrial analog material such as basalt,” said Prof. Cockell. “It really is the first mining experiment in space, if you will. We haven’t actually created economically useful quantities of rare earth elements, but we have demonstrated the principle,” he told BBC News.
About 20% of the world’s copper and gold is currently mined with the help of microbial processes.
In recent years there has been a lot of talk about mining planets and asteroids to obtain raw materials that could then be returned to Earth.
Professor Cockell still cannot see the economic reasons for this; it would be even cheaper to look for – and mine – minerals here on Earth, he says. But the argument for using resources in situ on other worlds is compelling, according to him.
Astronauts from the US space agency (NASA) will try to use the buried ice for drinking water when they return to the moon at the end of this decade. And as early as next year, the American Perseverance rover will perform an experiment that tries to produce oxygen from Mars’ carbon dioxide atmosphere, a potential turning point for any human settlement on the Red Planet.
Also, just this week, the European Space Agency (ESA) gave a contract to the British company Metalysis to develop its process to extract oxygen from lunar dust while producing aluminum, iron and other metal powders.
“The oxygen that we can release could be used as a propellant or to sustain life, or a presence on the moon. And the metal can be used to build different types of structures,” Metalysis CEO Ian Mellor told the BBC. .
As for the Edinburgh job, ways are being sought to improve efficiency.
BioRock on the ISS will soon be followed by BioAsteroid, a repeat experiment with the reactor but with shattered asteroid material rather than the Icelandic volcanic rock blocks used in the first study.
Professor Cockell said he also expected scientists to study at one time or another how mining bacteria could be designed to increase their productivity of useful products.
BioRock has received funding from ESA and the British Space Agency.
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