Moss Survives Months in Space
A well known adage claims, “A rolling stone gathers no moss.” But, what about a massive Space Station hurtling through the vacuum of outer space as it orbits planet Earth? Can it gather moss?
Japanese researchers from Hokkaido University in Japan wanted to learn more about how this hardy plant would hold up in an extreme exoatmospheric environment. The team placed moss sporophytes on the exterior of the International Space Station. To their surprise, nearly all the sporophytes survived despite outer space’s harsh conditions. The results of the research were published in iScience.
A Hardy Plant
Mosses are both ancient and resilient. Scientists think they evolved more than 400 million years ago. And, although they are less evolutionarily advanced than their seed-bearing cousins, mosses are quite hardy, according to a Cell Press news release.
Moss can thrive in extreme environments where other plants cannot — including the Himalayan peaks, inside active volcanoes, and in the frozen tundras of Antarctica. Tomomichi Fujita, who led the research team said in the news release that, “I began to wonder: could this small yet remarkably robust plant also survive in space?”
His team started testing how different structures of Physcomitrium patens, colloquially known as spreading earthmoss, held up when exposed to low gravity, high UV levels, and fluctuating temperatures they would likely encounter in an extraterrestrial environment. They found that earthmoss’s sporophyte structures could tolerate UV radiation levels that killed juvenile moss and moss stem cells.
The team hypothesized that this was because these sporophytes had developed protective structures that allowed them to survive mass extinction events in Earth’s pre-historic eras.
Moss in Outer Space
In 2022, Space.com reported, a package containing spreading earthmoss spores hitched a ride with the Cygnus cargo spacecraft heading to the International Space Station (ISS). When it arrived, astronauts placed the moss on the station’s exterior where the spores were exposed to space’s extremes.
After spending 238 days clinging to the ISS’s outer shell, the sporophytes headed back to Earth on a Dragon cargo capsule. Back on Earth, Fujita’s team examined the spores. They were shocked to find that a full 80 percent of the moss spores were still alive after nine months in space. Moreover, nearly 90 percent of the spore survivors could still germinate.
“We expected almost zero survival, but the result was the opposite: most of the spores survived,” Fujita explained in the news release. We were genuinely astonished by the extraordinary durability of these tiny plant cells. Most living organisms, including humans, cannot survive even briefly in the vacuum of space.”
He added, “However, the moss spores retained their vitality after nine months of direct exposure. This provides striking evidence that the life that has evolved on Earth possesses, at the cellular level, intrinsic mechanisms to endure the conditions of space.”
A Starting Point
Based on their analysis of the surviving spores, Fujita’s team hypothesized that the spores could have survived in an extraterrestrial environment for much longer than 238 days – possibly thriving on ISS’s exterior for up to 15 years, explained the news release.
For now, the study proves that life can find a way even in space’s icy and airless vacuum. Fujita said, “This study demonstrates the astonishing resilience of life that originated on Earth.”
The team hopes that their research will facilitate future research and open up future possibilities of planting seeds in alien soils or even growing plants in outer space.
As scientists continue to study the possibility of germinating and spreading plant life beyond Earth, these moss spores’ incredible survival story suggests that some forms of life may be better suited to the challenges of an extraterrestrial environment than researchers once expected.
