Nov 27, 2025 21:00:00

Moss can survive in the vacuum of space for up to nine months

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A research team led by Professor Tomomichi Fujita of Hokkaido University has confirmed that the moss Physcomitrella patens, a widely used model organism, maintains a high survival rate even after being exposed to the harsh conditions of space outside the International Space Station (ISS) for nine months, and that it germinates after returning to Earth.

Extreme environmental tolerance and space survivability of the moss, Physcomitrium patens: iScience
https://www.cell.com/iscience/fulltext/S2589-0042(25)02088-7

Moss Survives 9 Months in Space Vacuum
https://scienceclock.com/moss-survives-9-months-in-space-vacuum/

Moss in space: spores survive nine-month ride on outside of ISS | Biology | The Guardian
https://www.theguardian.com/science/2025/nov/20/moss-spores-survive-outside-international-space-station-iss

Mosses are the first group of plants to move from water onto land approximately 500 million years ago, and have an evolutionary history of adapting to harsh environments such as dryness, ultraviolet rays, and sudden temperature changes. Previous space experiments have mainly focused on seed plants such as crops, but this time, to verify the tolerance of mosses to extreme environments, a long-term exposure experiment was conducted using the Kibo Exposed Facility on the ISS.

Prior to the experiment, the research team conducted stress tests on Earth that mimicked the space environment, exposing different tissues of the moss , namely the protonema, asexual buds , and spores enclosed in sporangia, to intense ultraviolet light, freezing at -80°C, heating at 55°C, and a vacuum.

The survival rate of protonemata was 0% at an ultraviolet irradiation dose of 10kJ/ ^m² , but the spores enclosed in sporangia maintained a 27% germination rate even when exposed to 12MJ/ ^m² , more than 1,000 times that amount. Regarding resistance to temperature changes, protonemata died within four days when frozen at -80°C or exposed to a high temperature of 55°C, but 80% of spores survived under frozen conditions and 36% under high temperature conditions even after 30 days.

Based on the results of this ground experiment, an exposure experiment was conducted outside the ISS for 283 days.

The specimen, Physcomitrella patens, was exposed to a vacuum, microgravity, extreme temperature changes, and space radiation. However, when it was cultured after returning to Earth, it recorded a germination rate of 97% under conditions where ultraviolet rays were blocked, and 86% under conditions where it was exposed to direct ultraviolet rays.

Although the intense ultraviolet rays in space caused some decomposition of chlorophyll a, a pigment essential for photosynthesis, other pigments remained stable, and it was confirmed that this did not significantly impede growth after germination.

Professor Fujita said of the results, 'This survival rate defies expectations,' suggesting that mosses could potentially be used as the foundation of ecosystems in future extraterrestrial environments, such as the Moon or Mars, helping to produce oxygen and form soil. However, experts point out that this experiment only demonstrated the plants' ability to survive in a dormant state, and further research is needed to determine whether plants can actually grow and thrive in different gravity and atmospheric compositions.