In a remarkable demonstration of life’s tenacity, moss spores have survived nine months exposed to the harsh conditions of outer space, with an impressive 86% successfully germinating upon their return to Earth. Published November 20 in iScience, the findings suggest that transporting plant life to other celestial bodies—like the Moon or Mars—may be more feasible than previously thought.
Resilience Beyond Earth
Researchers led by biologist Tomomichi Fujita of Hokkaido University sent spores of the Physcomitrium patens moss on an extended orbital voyage aboard the International Space Station. Despite facing extreme vacuum, high radiation levels, and temperature fluctuations, the majority of the spores not only survived but resumed growth when reintroduced to terrestrial conditions.
“Beautiful,” was Fujita’s succinct reaction when observing the germination rate.
The success of this experiment places moss spores among a growing list of organisms—including certain bacteria, lichens, plant seeds, and tardigrades—proven capable of enduring prolonged exposure to space. While initial testing in simulated environments suggested high survival odds, Fujita remained cautious, noting that “multiple stress conditions may have a synergistic bad effect.”
Protective Mechanisms at Play
Astrobiologist Daniela Billi of the University of Rome Tor Vergata wasn’t surprised by the results. The spores’ dormant, dehydrated state provided inherent protection against environmental extremes. Further bolstering their resilience was the sporangium, a natural casing that shielded them from damaging radiation.
However, Billi cautions that maintaining life in an active, hydrated state presents a far greater challenge. Metabolically active seeds are significantly more vulnerable to the combined effects of radiation, vacuum, and microgravity.
Implications for Space Colonization
Despite these hurdles, the ability of dormant plant spores to survive in space has profound implications for long-term space missions and potential colonization efforts. The possibility of transporting and cultivating plants on other planets to provide oxygen, food, and medicine is now more realistic. Fujita envisions future greenhouses on Mars, populated with plant species engineered for resilience.
Next Steps: Assessing Long-Term Damage
The next phase of research will focus on quantifying the DNA damage accumulated by the spores during their nine months in space, and how effectively the resulting plants repair that damage. Billi explains that the unique radiation mix in space—a combination of cosmic and solar radiation not typically encountered on Earth—presents an unprecedented stressor.
Prior experiments, conducted roughly 17 years ago, showed that seeds from mustard and tobacco plants survived over a year and a half in space, although initial generations exhibited impaired growth. However, subsequent generations recovered, demonstrating the capacity for genetic repair.
Ultimately, the success of the Physcomitrium patens spores reinforces the idea that life is remarkably adaptable, and that interplanetary agriculture may soon move from science fiction to scientific reality.
