A study published in iScience reports Physcomitrium patens moss spores survived nine months on the exterior of the International Space Station, with more than 80% surviving and germination rates reaching up to 97% for spores shielded from UV light.

The findings suggest mosses could serve as a starting point for off-world plant cultivation and initial ecosystems on the Moon or Mars, informing future extraterrestrial agriculture and habitat support.

Remarkably, the spores germinated after being returned to Earth, indicating potential for revival post-mission.

Experts caution the study does not address cosmic ionizing radiation beyond ISS protection, a major challenge for deeper space missions.

Dr. Tomomichi Fujita emphasizes that the study covers survival and early revival, while highlighting the need for further research on growth and viability in varied space environments.

The research does not claim evidence of extraterrestrial life but supports the idea that life's building blocks could be widespread and persistent beyond Earth.

Related experiments on the ISS with Antarctic mosses exposed to radiation are being conducted to observe recovery under low gravity, with results pending.

While spore resilience is promising, ISS conditions do not replicate deep-space environments, so growing plants in true space conditions remains a broader challenge.

Dr. Agata Zupanska notes that external ISS conditions differ from deep space, and the practical goal is extraterrestrial plant growth, not just surviving spores.

Astrobiologist Daniela Billi points out that the dormant, dehydrated state and protective sporangium likely aided survival, whereas hydrated, active samples would face greater radiation and environmental stress.

SETI Institute scientist Agata Zupanska highlights radiation as a core concern for seed viability in deep space and notes moss is highly radiation-resistant on Earth.

Physcomitrium patens is a model organism in plant biology due to its sequenced genome and relevance to studying plant evolution and stress tolerance.