In 2022, a species of moss survived for nine months outside the International Space Station (ISS), enduring the harsh conditions of space. The study, published Thursday (November 20) in the journal iScience, explored whether moss, an early land plant known for its resilience, could withstand long-term exposure to the vacuum of space.
Researchers from Hokkaido University in Japan, led by Professor Tomomichi Fujita, attached moss spores to the ISS exterior. They found that over 80% of the spores survived and were capable of reproducing upon their return to Earth. Fujita explained that this experiment shows how life on Earth has developed intrinsic mechanisms to endure space conditions. Mosses, which descended from ancestral plants that colonized dry land around 450 million years ago, are known for their hardiness in extreme environments, from the Antarctic tundra to volcanic lava fields.
The study focused on a type of moss called Physcomitrium patens. Researchers initially tested the moss in simulated space conditions on Earth, exposing it to extreme temperatures, vacuum conditions, and high levels of UV radiation. They found that sporophytes, the reproductive structures of the moss, were particularly resilient. In March 2022, hundreds of these sporophytes were sent to the ISS aboard a Northrop Grumman spacecraft. After 283 days in space, the samples returned to Earth in January 2023 on a SpaceX mission.
The findings suggest that moss spores could survive in space for much longer, potentially up to 15 years. This resilience could be used to develop agricultural systems in space and explore the potential for growing plants on extraterrestrial soils. Fujita hopes this research will pave the way for constructing ecosystems in environments like the Moon and Mars.