In the heart of one of the world's most infamous nuclear disaster zones, a remarkable organism has evolved a survival trick that could revolutionise human space exploration. Deep inside the ruins of Chernobyl's Reactor No. 4, a peculiar fungus doesn't just endure extreme radiation – it consumes it.
The Radioactive Discovery in the Exclusion Zone
Cladosporium sphaerospermum was first identified in the late 1990s by Ukrainian microbiologist Nelli Zhdanova of the National Academy of Sciences. It was one of 39 species found thriving on the walls of the reactor unit, which catastrophically melted down in 1986. That disaster led to the permanent evacuation of the city of Pripyat and the creation of a 19-mile exclusion zone that remains in place today.
The fungus, which can appear as olive green, brown, or black and is often mistaken for common black mould, possesses a suite of extraordinary adaptations. It is xerotolerant, meaning it can grow with very little water. While its spores can cause respiratory irritation in humans, its most significant feature lies in its melanin – the same pigment that colours human skin and hair.
From Radiosynthesis to Space Shields
Researchers believe the melanin in Cladosporium sphaerospermum allows it to perform a process analogous to photosynthesis. Instead of using sunlight, however, it absorbs radiation and converts it into chemical energy, a mechanism dubbed radiosynthesis.
This unique ability has captured the attention of space scientists. Biochemist Nils Averesch from the University of Florida explained to the BBC that the fungus shows remarkable resilience to cosmic rays – the high-energy radiation from supernovas and our Sun that poses a severe health risk to astronauts on long-duration missions.
With the US Artemis programme aiming for a lunar return by 2024 and a permanent base by 2028, and with ambitions for crewed missions to Mars, finding effective radiation shielding is a critical hurdle. As Averesch noted, 'The foremost threat to the short – and long-term health of astronauts on long-duration deep-space missions is radiation.'
Fungal Furniture for Future Space Habitats
In a groundbreaking experiment in 2018, samples of the fungus were sent to the International Space Station. Over 26 days, exposed to the full spectrum of cosmic radiation, the fungi grew 1.21 times faster than control samples on Earth. While micro-gravity may have played a role, tests confirmed the melanin acted almost like a biological force field. Remarkably, even a thin layer of the mould in a petri dish provided measurable protection.
This has led to visionary proposals. NASA astrobiologist Lynn J. Rothschild has suggested the future possibility of constructing fungal furniture or wall panels within spacecraft or planetary habitats to act as living, self-sustaining radiation barriers.
The potential applications extend beyond space travel. The same properties that allow the fungus to thrive in Chernobyl could eventually be harnessed to help clean up radioactive waste sites on Earth. What began as a biological curiosity in a concrete sarcophagus in Ukraine may well become a cornerstone technology for humanity's journey to the stars.
