Researchers also use the term“ radiotrophy” for the broader idea that radiation might help power the organism’ s metabolism, although that idea remains controversial and hard to prove.
CubeLab module on the ISS
Researchers sent the fungus to the International Space Station( ISS) inside a CubeLab module that ran on its own.
The ISS orbits inside much of Earth’ s magnetic protection, but it still gets more radiation than you do on the ground.
The box held two Raspberry Pi computers, a camera with a built‐in light source, temperature and humidity sensors, and two radiation sensors.
A split Petri dish held the samples. One half contained potato dextrose agar with the fungus.
The other half held the same agar without the fungus, so it served as a built‐in negative control( a comparison sample without fungus).
Space radiation on the ISS
One radiation sensor sat under each half of the dish, so both sensors“ looked up” through almost the same materials. Only one side developed a layer of fungal biomass.
That setup mattered because radiation around the ISS changes as the station moves through orbit.
The team also positioned the dish and sensors to face away from Earth. Shielding from the planet and the station’ s structure can change what the detectors record.
Cladosporium sphaerospermum growth
The team kept the inoculated plates cold at about 39 ° F( 4 ° C) during transit so the fungus would not grow much before observations began.
On the ISS, the system took photos every 30 minutes for 576 hours and collected more than a thousand images. It recorded temperature and humidity frequently and logged radiation counts about once every 1.5 minutes, on average.
The full run lasted about 622.5 hours, and each radiation sensor logged tens of thousands of counts.
The researchers needed a way to measure growth without touching the dish. They processed the images and treated brightness changes as a stand‐in for how much fungal material covered the agar.