Moss Spores Survive Space Conditions, Germinate on Earth

Moss spores have demonstrated the ability to survive the harsh conditions of outer space and successfully germinate back on Earth. According to a study published in the journal iScience on November 20, 2023, researchers from Hokkaido University, led by Tomomichi Fujita, found that more than 80% of the Physcomitrium patens, commonly known as spreading earthmoss, endured nine months of exposure to the vacuum of space aboard the International Space Station.

This research marks a significant milestone, as it is the first documented evidence that an early land plant can survive long-term space conditions. Fujita's curiosity about the moss's potential to withstand extreme environments prompted this investigation, inspired by the plant's ability to thrive in some of the Earth’s most challenging habitats, such as the Himalayas and Antarctic tundra.

The researchers designed an experiment to expose moss sporophytes to simulated space conditions, including intense UV radiation, extreme temperatures, and a vacuum environment. They assessed the resilience of three moss forms: protenemata, brood cells, and sporophytes.

They discovered that sporophytes exhibited remarkable durability, with a UV tolerance approximately 1,000 times greater than the other structures. In March 2022, the team sent hundreds of sporophytes into orbit on the Cygnus NG-17 spacecraft, where they were attached to the ISS for 283 days.

Upon return to Earth in January 2023, over 80% of the spores survived, and nearly all of those that survived were able to germinate in laboratory conditions. Although there was a 20% drop in chlorophyll a levels, the spores remained healthy, suggesting their capability to adapt and thrive even after extreme exposure.

According to Fujita, these findings underscore the resilience of life that originated on Earth and could have profound implications for future studies on extraterrestrial agriculture. The research team is optimistic that this study will pave the way for creating sustainable ecosystems in environments like the Moon and Mars.

They also proposed a mathematical model indicating that these moss spores could potentially survive in similar conditions for up to 5,600 days, or roughly 15 years, although further research is necessary for conclusive validation.

This groundbreaking work was supported by the DX scholarship from Hokkaido University, JSPS KAKENHI, and the Astrobiology Center of National Institutes of Natural Sciences.