Several projects and designs for space settlements have been made over the last years, but there are plenty of objections to colonization. A major concern regarding interplanetary travel is radiation exposure. On Earth, people are protected against radiation. Its magnetic field and atmosphere serve as a shield, but as approaching space, the safety blanket disappears. An astronaut can absorb up to 60% of the maximum recommended lifetime dosage of radiation in a single trip to Mars. Researchers from Stanford and North Carolina universities suggest that a type of fungi could be the solution.
They have been analyzing several species of fungi found in one of the most radioactive places on the planet (Chernobyl) and noticed that they are “feeding” on the extreme levels of radiation. The fungus blocked radiation on the international space station (ISS), so scientists believe it could be adapted for space travel.
The research team discovered that the fungus possesses the ability to multiply in the still-extreme radiation environment through radiosynthesis. In the process of radiosynthesis, fungi like Cladosporium sphaerospermum, use a pigment known as melanin to absorb radiation and then turn gamma rays into chemical energy. Knowing that, they decided to do a study on the ISS to see how the mold would behave in blocking space radiation. The team set up a petri dish with two sides: a control containing no fungi on one side and C. sphaerospermum fungi on the other. A radiation detector was placed underneath the petri dish, which would monitor radiation levels every 110 seconds for 30 days.
The proof-of-concept study showed that the fungi survived just fine in the microgravity environment and were able to block some of the incoming radiation, lowering the levels by nearly 2%. As the fungal layer was quite thin (1.7 mm), it is safe to affirm “this shows the ability of C. sphaerospermum to significantly shield against space radiation,” researchers said. The team deduced that a 21-cm thick layer would “largely negate” the annual dose of radiation one would be exposed to on Mars. Moreover, it could be reduced to just 9 cm if combined with Martian soil.
A big advantage is that since the fungus self-replicates from microscopic amounts, astronauts would then need to carry just a small amount. Once on Mars, it would only take some nutrients for the fungus to grow into a self-healing, self-replicating shield to protect any bases.