In one of the most surprising biological discoveries of recent years, scientists have confirmed that a humble species of moss can survive the brutal conditions of outer space. The experiment, led by an international team working on Japan’s Kibo module aboard the International Space Station (ISS), revealed that Physcomitrium patens, a common moss found on Earth, endured nine months of exposure to vacuum, cosmic radiation, intense ultraviolet light, and extreme temperature swings—and still came back to life.
This result not only shows how tough simple plant life can be, but also provides new clues for future space exploration, long-term habitat building, and even the possibility of life traveling between planets.
A Small Plant With Big Survival Skills
For the experiment, scientists placed moss samples outside the ISS, where conditions are far harsher than anything found on Earth. Without the atmosphere to protect them, organisms are blasted by UV rays, bombarded by radiation, and subjected to temperatures that swing from boiling to freezing within minutes. Most living things die within seconds in such an environment.
But this moss didn’t just survive—it thrived once it returned home.
When the samples were brought back to Earth, researchers found that more than 80% of the spores were still viable. Even more impressive, many of them started reproducing again almost immediately, as if nothing unusual had happened.
The experiment analyzed three different moss cell types, but the real stars were the sporophytes. These structures, which naturally protect and distribute spores, acted like tiny biological shields. Their outer layers helped guard the spores from light damage, radiation, and moisture loss—giving them a remarkable ability to withstand the stress of space.
Could Moss Stay Alive in Space for 15 Years?
One of the most exciting conclusions from this study is the estimated long-term survival potential. By examining the condition of the spores, scientists calculated that Physcomitrium patens could remain viable in the vacuum of space for up to 15 years. That’s longer than the lifespan of many small satellites orbiting Earth.
While the moss pigments suffered noticeable damage, the core biological structures stayed intact. This means moss may belong to a rare group of Earth organisms capable of surviving long periods beyond our atmosphere.
Why This Discovery Matters for Space Exploration
The idea of growing plants in space is nothing new. Most experiments have focused on food crops, such as lettuce, tomatoes, and wheat, because astronauts will eventually need sustainable diets on the Moon or Mars. But moss offers something completely different—and equally valuable.
Moss is:
Lightweight
Low-maintenance
Highly resilient
Capable of growing in poor soils
Useful for water and air cycling
These traits make it an ideal early colonizer in off-Earth environments. If humans ever build long-term bases on the Moon or Mars, moss could help prepare the surface by creating organic material, keeping humidity stable, or even improving air quality inside habitats.
In other words, moss could act as a pioneer species—a lifeform that arrives first, survives easily, and helps make the environment more suitable for other plants.
A Boost for the Panspermia Theory
The findings also lend weight to the scientific theory known as panspermia. This idea suggests that life might naturally travel between planets, carried by rocks or debris blasted into space by asteroid impacts or volcanic eruptions.
If moss spores can survive 15 years in space, it becomes more believable that microscopic life could drift across the solar system over long periods and still remain viable. While this doesn’t prove panspermia, it certainly keeps the door open.
A New Chapter for Space Biology
This groundbreaking study adds moss to a shortlist of Earth organisms—such as tardigrades and certain microbes—that can withstand outer space without artificial protection. The results offer new opportunities for space farming, extraterrestrial ecosystem design, and deeper understanding of life’s limits.
Most importantly, this research shows that even some of the simplest plants on Earth possess extraordinary survival abilities. As we prepare for future missions to the Moon, Mars, and beyond, discoveries like this remind us that the natural world still has surprises waiting on Earth and in space.
Source:
“Extreme environmental tolerance and space survivability of the moss, Physcomitrium patens.” iScience, 2025.