Chernobyl Fungus Feeding on Gamma Radiation Emerges as a Surprising Contender for Future Space Radiation Shields

A species of fungus found in the irradiated ruins of the Chernobyl Exclusion Zone is receiving renewed interest from space scientists, who are examining whether its unusual resilience could help shield astronauts from cosmic radiation. The organism, often described as a fungus 'feeding on gamma radiation', has become a focal point in early research into biological protection systems for long-duration missions.

The melanised fungi, including Cladosporium sphaerospermum, were first identified clinging to surfaces near the destroyed reactor despite its intense radiation environment. Their cell walls contain melanin, a pigment that appears to absorb and dissipate ionising radiation. Laboratory evidence suggests that melanin can protect fungal cells by neutralising free radicals produced during radiation exposure.

Although the organism's behaviour is striking, scientists emphasise that the idea of deploying such fungi as radiation shields remains at a conceptual stage. Experiments, including a 2022 International Space Station (ISS) trial, confirm that the fungus can endure elevated radiation and slightly lower radiation flux, but turning this into a practical defence for spacecraft or planetary habitats will require far more research.

Scientific Interest Rooted in Chernobyl's Extremes

After the 1986 reactor explosion, the exclusion zone became one of the most radioactive environments on Earth. Yet biologists found black fungi, often growing in streaks along walls and metal structures, displayed radiotropism, meaning they grew towards sources of gamma radiation. This unusual response prompted scientists to investigate whether the organisms were not merely surviving radiation but actively using it.

Subsequent experiments exposed melanised fungi to levels hundreds of times above natural background radiation. These strains consistently outperformed non-melanised varieties, showing enhanced growth that led to the hypothesis of 'radiosynthesis'. This process, still under study, suggests the fungi may convert radiation energy into usable chemical energy in a manner loosely comparable to photosynthesis.

Space-Based Experiments and Practical Barriers

Interest in practical applications increased when C. sphaerospermum was cultivated aboard the ISS. Over 30 days, the fungal layer reduced detected radiation by around two per cent compared with a control. While a limited effect, the findings indicate that melanised fungi may form part of a broader approach to shielding. Some projections suggest that a layer approximately 21 centimetres thick could meaningfully lower radiation exposure on the Martian surface.

However, substantial barriers remain. A biological layer capable of meaningful protection would be bulky, and maintaining fungal growth in microgravity presents engineering challenges. Containment systems, environmental regulation, and long-term stability would all require sophisticated design. Researchers note that melanin provides only partial shielding compared with metals, meaning fungi could complement, but not replace, conventional materials.

Potential Future Uses

Advocates of bio-hybrid space systems argue that integrating fungal shielding with traditional materials or Martian regolith could reduce payload mass, offer limited self-repairing capability, and support more sustainable habitat construction. The idea forms part of a wider move in space science towards using biological processes to meet engineering challenges.

The Chernobyl fungus is far from an operational solution, but its uncanny ability to thrive by effectively feeding on gamma radiation continues to intrigue scientists. As research progresses, it may offer insights into how life itself could contribute to protecting astronauts as humanity pushes deeper into space.