ISS experiment reveals how we could mine rocks in space with 400% efficiency

Getting minerals in space may be a little easier than we thought, with the help of some of the smallest inhabitants on Earth.

Experiments aboard the International Space Station have shown that bacteria can improve space mining efficiency by more than 400 percent, offering a much easier way to access materials such as magnesium, iron and rare earth minerals that we use extensively in the world. electronics and alloys.

Here on Earth, bacteria play a very important role in extracting minerals from the soil. They are involved in natural atmospheric agents and in the degradation of rocks, releasing the minerals contained in them.

This bacterial ability to leach metals from their environment has been harnessed to aid in human mining operations; called biomining, it has a number of benefits. It can help reduce dependence on cyanide for gold mining, for example. Bacteria can also help decontaminate polluted soils.

In space environments, such as asteroids, the Moon and even Mars, mining will be a valuable tool as we set up human outposts. Transporting material from Earth is expensive; even the least expensive option, SpaceX’s Falcon Heavy, costs $ 1,500 per kilogram (2.2 lb) of payload. So the scientists studied the feasibility of biomination in space.

‘Microorganisms are very versatile and as we move through space, they can be used to carry out a variety of processes,’ explained astrobiologist Rosa Santomartino of the University of Edinburgh in the UK. “Elementary mining is potentially one of them.”

Over a 10-year period, the team developed a small matchbox-sized device called a biomining reactor that could easily be transported and installed on the International Space Station. Then, in July 2019, 18 of these biomining reactors were shipped to the ISS for experiments in low Earth orbit.

(Cockell et al., Nature Communications, 2020)

Each biomining reactor contained a bacterial solution that submerged a small piece of basalt, a type of volcanic rock abundant on the Moon. Over a three-week period, the basalt in each reactor was exposed to the bacterial solution to determine if the bacteria could perform the same degrading function as rocks in a low gravity environment.

In simulating Mars gravity, simulated Earth gravity (using a centrifuge), and microgravity, the team performed experiments with separate solutions of three different bacteria: Sphingomonas desiccabilis, Bacillus subtilis is Cupriavidus metallidurans. A bacteria-free control solution was used as a reference base.

The researchers found that there were no significant differences in bacterial leaching performance based on severity and per conditions B. subtilis is C. metallidurans, the extraction of rare earth minerals was respectively less and not significantly different from the control solution.

however, the S. desiccabilis The solution led to the extraction of significantly more rare earth minerals from basalt than the control solution.

“For S. desiccabilis, in all individual rare earth elements and in all three gravity conditions on the ISS, the organism leached 111.9% to 429.2% of the non-biological controls, “the researchers wrote in their paper.

Since microgravity has previously been shown to influence microbial processes, the similarity between the concentrations of mined minerals under all three gravity conditions was a surprise. However, the team noted that all three bacteria reached similar concentrations in all three gravity conditions, likely because they had enough nutrients to do so.

They concluded that, with sufficient nutrients, biomination is therefore possible under a range of gravity conditions.

“Our experiments support the scientific and technical feasibility of biologically enhanced elemental extraction throughout the Solar System,” said astrobiologist Charles Cockell of the University of Edinburgh.

“While it is not economically feasible to mine these elements into space and bring them to Earth, space biomination could potentially support a self-sufficient human presence in space.

“For example, our findings suggest that the construction of robotic and man-made mines in the Moon region Oceanus Procellarum, which has rocks with enriched concentrations of rare earth elements, could be a fruitful direction of human scientific and economic development beyond the earth . “

The research was published in Nature Communications.