Though it may seem unassuming, Earth’s moss is remarkably resilient. It thrives in extreme conditions—from the freezing, low-oxygen heights of the Himalayas to the scorching sands of Death Valley, and even across lava fields of active volcanoes. Now, space can be added to its list of habitats.

Figure 1. Moss Survives 283 Days in Space, Stunning Scientists.

“Most living organisms, including humans, cannot survive even a short time in the vacuum of space,” said Tomomichi Fujita, a biologist at Hokkaido University and co-author of the study. “Yet these moss spores maintained their vitality after nine months of direct exposure, offering compelling evidence that life on Earth has, at the cellular level, built-in mechanisms to withstand the harsh conditions of space.” Figure 1 shows Moss Survives 283 Days in Space, Stunning Scientists.

Preparing the Moss

To investigate, Fujita’s team focused on Physcomitrium patens, a well-studied moss species also known as spreading earthmoss. They exposed the moss to a simulated space environment, featuring intense ultraviolet (UV) radiation, extreme temperature fluctuations, and vacuum conditions.

The researchers then examined three different moss structures: juvenile moss (protenemata), specialized stem cells that form under stress (brood cells), and reproductive sporophytes that contain the spores. Testing these distinct structures allowed the team to identify which part of the moss was most likely to survive the harsh conditions of space.

“We expected that the combined stresses of space—including vacuum, cosmic radiation, extreme temperature swings, and microgravity—would inflict far more damage than any single stress alone,” Fujita explained.

The team found that UV radiation was the most damaging factor, but among the three moss structures, the sporophytes proved the most resilient. All juvenile moss succumbed to the intense UV or extreme temperatures, while brood cells fared slightly better. The sporophytes, however, demonstrated roughly 1,000 times greater tolerance to UV radiation. Remarkably, the spores could survive and germinate after exposure to temperatures as low as −320°F for over a week, as well as endure highs of 131°F for a month.

The researchers attribute this resilience to the protective coating surrounding each spore. This layer absorbs UV radiation and shields the inner spore both physically and chemically, preventing damage. It is likely an evolutionary adaptation that enabled bryophytes—the plant group moss belongs to—to transition from aquatic to terrestrial life around 500 million years ago. Moss has since survived multiple mass extinction events.

Moss Goes to Space

To test this evolutionary advantage in the harshest environment, the team sent the spores beyond Earth’s stratosphere to the International Space Station. Astronauts attached the sporophyte samples to the exterior of the station, where they remained exposed to space for 283 days. In January 2023, the moss returned to Earth aboard SpaceX CRS-16 for analysis.

Over 80% of the spores survived the journey, and all but 11% of them were able to germinate in the lab. Tests of chlorophyll levels showed mostly normal readings, with only a 20% reduction in chlorophyll a—a pigment especially sensitive to changes in light exposure. Despite this minor decrease, the spores’ overall health remained unaffected.

How Long Could Moss Survive in Space?

To estimate how much longer the spores might endure, the team used pre- and post-flight data to build a mathematical model. According to their calculations, the spores could potentially survive up to 15 years—or about 5,600 days—in space. The researchers caution, however, that this is a preliminary estimate based on a single experiment, and a larger dataset would be needed for more accurate predictions.

“Ultimately, we hope this work opens a new frontier for constructing ecosystems on extraterrestrial bodies such as the Moon and Mars,” Fujita said. “I hope our moss research can serve as a starting point for future exploration.”

Source: POPULAR SCIENCE

Cite this article:

Priyadharshini S (2025), Moss Endures 283 Days in Space, Astonishing Biologists, AnaTechMaz, pp.611