- Recently, researchers sent mold growing at the site of the Chernobyl accident to the International Space Station for study.
- Mold seems to feed on radiation, so early research shows that it may help protect astronauts from the dangerous radioactivity of space.
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Astronauts carry many risks in space, but exposing themselves to dangerous radiation is one of the greatest. On the International Space Station, astronauts are exposed to up to 160 milliseverts of radiation during a six-month mission, according to NASA, which is about 1,600 chest x-rays and 26 times more than the average US citizen receives. Mars is even worse; an astronaut who made an 18-month journey to the Red Planet would be exposed to 1,000 pieces of radiation or 10,000 chest x-rays.
To protect themselves, astronauts usually rely on radiation shields made of plastics or metals such as aluminum and stainless steel. But they can be severe and vulnerable to damage.
So in 2018, some high school students from Durham County, North Carolina, suggested an unusual solution to this problem: Make a shield out of a uniform.
In particular, they proposed cladosporium sphaerospermum, an organism that appears to feed on nuclear radiation just as most plants feed on sunlight. Mold thrived in the Chernobyl Exclusion Zone, the site of the 1986 nuclear recession, which is still one of the most radioactive sites on Earth.
Students under Graham Schunk, a current sophomore at the North Carolina School of Science and Mathematics, received samples of mold from a company in Minnesota. With the help of research company Space Tango, they exploded into space in December 2018.
At the International Space Station, astronauts placed mold samples in Petri dishes, leaving the empty portion of each dish empty. Geiger counters then measured the radiation level under the dishes every 110 seconds for 30 days. The results showed that the radiation level decreased at the height of the mold growth: the meters measured a decrease in the average radiation level by 2.4% under the sides covered with mold.
Preliminary findings from this experiment were uploaded to the bioRxiv research archive on July 17, but they have not yet been verified. And yet they suggest that mold can act as protection against radiation in space.
This is because mold seems to absorb radiation and convert it into chemical energy in a process called radiosynthesis. This is similar to photosynthesis, a process that most plants use to convert sunlight into energy.
Schunk and other researchers have suggested that if the mold were about 21 centimeters thick, it could provide a person with adequate protection from radiation levels on Mars. The protection would be stronger if the mold surrounded the object completely, they think, instead of just shielding one side, as was done in the study.
Mold also has a great advantage over other types of radiation screens, the researchers also noted, because it can grow and replenish in space. This means that the microscopic amount of C. sphaerospermum may be all that is needed at the start of the launch – so it will not add weight to the rocket. This could be a change of game, as NASA estimates that launching something into space costs about $ 10,000 a pound.
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