Researchers have confirmed that moss spores can withstand the harsh conditions of outer space for extended periods – nearly nine months on the exterior of the International Space Station (ISS) – and remain viable upon return to Earth. This discovery challenges assumptions about the limits of life and could have significant implications for future space exploration and potential extraterrestrial ecosystems.
Unexpected Survival in Extreme Conditions
The study, led by Tomomichi Fujita of Hokkaido University in Japan, involved exposing spores of Bryum argenteum (spreading earthmoss) to the vacuum, radiation, and temperature fluctuations of space. Despite expectations of near-total mortality, over 80% of the sporophytes survived the 283-day mission. Even more remarkably, nearly 90% of the surviving spores were able to germinate and grow under laboratory conditions.
This resilience is particularly noteworthy given that most organisms, including humans, cannot survive even brief exposure to the vacuum of space. Fujita’s team found that while UV radiation posed the greatest threat, the sporophytes exhibited an extraordinary ability to endure the combined stresses.
Why Moss Matters: Evolutionary Adaptation
Mosses, among the oldest terrestrial plants, evolved over 400 million years ago, predating vascular systems that transport water and nutrients. Their simplicity does not equate to fragility; in fact, many species thrive in extreme environments on Earth – from Arctic tundra to deserts.
This study suggests that this inherent hardiness extends beyond our planet. The moss spores possess intrinsic cellular mechanisms that allow them to withstand conditions lethal to most other life forms. This isn’t entirely surprising; similar resilience has been observed in bacteria and tardigrades. However, the survival rate of moss spores after such prolonged exposure is exceptionally high.
Implications for Space Exploration
The research could pave the way for establishing sustainable ecosystems on other planets. Fujita hopes this work will serve as a starting point for building life-support systems on the Moon, Mars, or beyond.
Mathematical modeling suggests that the sporophytes could survive in space for approximately 5,600 days, indicating a far greater tolerance than initially anticipated. While chlorophyll a levels were reduced by 20% during the mission, the spores remained functional.
“This study demonstrates the astonishing resilience of life that originated on Earth,” Fujita stated. This finding highlights the potential for using simple organisms like moss to create self-sustaining environments in extraterrestrial settings.
The ability to cultivate plants in space would not only provide food and oxygen for future astronauts but also contribute to psychological well-being by offering a connection to Earth’s biosphere. This research underscores the remarkable adaptability of life and opens new possibilities for long-term space colonization.
