An experiment done aboard the International Space Station demonstrates the potential of a resistant fungus to protect astronauts from cosmic radiation. This mushroom has already proven its worth in one of the most hostile places on Earth: the ruined Chernobyl nuclear power plant.
Galactic cosmic radiation remains a troubling impediment to a sustained human presence in space.
This unresolved issue is starting to get a bit urgent, with NASA’s Artemis Moon landing scheduledby 2024, along with promises of manned missions to Mars and the establishment of Martian colonies. A 360-day round trip to the red planetfor example expose unprotected astronauts two thirds of their allowed lifeimmediate exposure, or 662 mSv, making them vulnerable to numerous health risks, including fatal cancers.
SScientists and engineers have proposed various solutions to address the problem, including a Star Trek-I like it deflector shield and a proposal to make radiation protection bricks from the dusty Martian regolith.
But like new investigation loaded in prepress bioRxiv notes, a ready-made solution may already exist in the form of an Extremophilous fungus known as Cladosporium sphaerospermum.
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Scientists first discovered this organism in 1886, and it has been found growing in radioactive environments, including cooling pools at the damaged Chernobyl nuclear power plant plant, where radiation levels are three to five orders of magnitude higher than normal background levels. C. sphaerospermum It is a radioactive melancholic fungus, an organism capable of converting radioactive energy into chemical energy, which it does by using melanin pigments within its cell walls. It sounds strange, but it is analogous to photosynthesis, in which plants convert the energy of visible light into useful energy.
“Melanin may also be the way the fungus protects itself from the harmful effects of radiation, with the ‘side effect’ of an extra energy boost, which has probablygives the fungus finds ideal habitats in radioactive environments “ Nils Averesch, co-author of the study and scientist at NASA’s Ames Research Center, explained in an email
Given the unusual radiation appetite for this mushroom, Averesch co-authors Graham Shunk and Xavier Gómez, former high school students with the Superior orbits “Go for the launch!” The program (a nonprofit STEM field it promotes) and others devised an experiment to determine how much radiation this organism could absorb in space. They also searched assess its suitability as a means of radiation shielding.
“They postulated that if an organism uses radiation, It should also be strong and capable of reducing it, also in space, “Averesch said. “They developed a concept for an experiment that would test this with radiation in space (since space radiation is quite different from radioactive environments on Earth) and were awarded through the Higher Orbits Foundation.”
The place chosen for this experiment was the International Space Station, which presents a unique radiation environment not unlike the surface of Mars.
To run the test, a Petri dish was divided in half, with one side with C. sphaerospermum and an empty side that serves as a negative control. The fungi were allowed to grow for 30 days, while the radiation levels were monitored every 110 seconds with a Geiger counter. The results showed that the fungi were able to adapt to the microgravity environment of the low Earth orbit and live on the incoming radiation. Furthermore, the experiment showed that a 1.7-millimeter-thick growth layer, or “fungal grass” as the researchers described it, blocked the incoming radiation somewhere between 1.82% to 5.04% compared to negative control.
“The error [range] it is due to uncertainty in the mathematical determination of this value, “Averesch said.” While this is not enough to sufficiently protect astronauts, it is a starting point for the further development of a living radiation shield. “
“In the experiment, we were able to demonstrate that the fungus not only thrives in ionizing radiation on earth but also in space, “he said Averesch. “In addition to not being destroyed by radiation … the fungus actually reduces radiation from the measured spectrum. “
The researchers hypothesize that a fungal lawn measuring 8.2 inches (21 centimeters) thick could “largely negate the equivalent annual dose of the radiation environment on the surface of Mars,” as they wrote in the study. C. sphaerospermum Therefore, it is classified as “among the most effective radiation attenuators”, making it a promising candidate to protect astronauts against galactic cosmic radiation.
As an added benefit, the fungus is a self-sufficient, self-replicating substrate capable of living on even the smallest doses of radiation and biomass. It can also be grown with different types of carbon. sources, such as organic waste.
“This significantly reduces the amount of protective material one would have to carry to Mars, which is perhaps what makes it most exciting, since mass en masse is very restrictive in any Mars mission scenario,” Averesch explained.
Averesch said that no single solution will likely solve the problem of space radiation, but that the fungus could be used as part of a multi-component system. The fungus is not harmful to humans, he said, but the exposure is probably minimal, anyway, because the microorGanism could grow within a double wall.
So, a promising start to this possible solution, but more experiments and data are needed necessary. Looking ahead, Averesch would like to conduct further tests with fungal growths “to strengthen the data and results of the study” in preparation for submission. the article to a peer-reviewed scientific journal.
If this solution really worked, future space explorers would be wise to recognize their fellow fungi, creatures capable of withstanding the intense radiation found inside the Chernobyl nuclear power plant. There is something strangely reassuring about that.
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