Moss are known for surviving in places that challenge most life, including the Himalayan peaks, the scorching deserts of Death Valley, the Antarctic tundra, and the cooling surfaces of energetic volcanoes. Their remarkable stability led researchers to look at moss sporophytes, the reproductive structures that hold the spores, in a good tougher setting: the outer space. According to a study published within the journal Nov. 20, greater than 80 percent of those ovules endured 9 months outside the International Space Station (ISS) and still returned to Earth still able to reproducing. This is the primary evidence that an early land plant can survive long-term exposure to space conditions.
“Most organisms, including humans, cannot survive even briefly in the vacuum of space,” says lead writer Tomomichi Fujita of Hokkaido University. “However, the moss spores retained their viability after nine months of direct exposure. This provides compelling evidence that life that has evolved on Earth has, at the cellular level, internal mechanisms to withstand the conditions of space.”
Asking if moss can survive beyond Earth?
Fujita began exploring the potential for “space mass” while studying military evolution. He was impressed by the masses’ ability to colonize the harshest environments on Earth. “I wondered: Can this small but remarkably strong plant survive in space?”
To investigate, Fujita’s team exposed F, also generally known as expanding Earth mass, to a simulated space environment, including intense UV radiation, extremely high and low temperatures, and vacuum-like conditions.
Examining the structure of moss Under this Extreme stress
The researchers compared three types of moss: proteinemata (juvenile moss), brood cells (stress-induced stem cells), and sporophytes (encapsulated spores). Their goal was to find out which structure had the best potential for bearing space.
“We expected that the combined stresses of space, including the vacuum, cosmic radiation, extreme temperature fluctuations, and microgravity, would do more damage than any stress alone.”
Their experiments showed that UV radiation posed the best threat, and sporophytes clearly outperformed other structures. Juvenile moss didn’t survive strong UV exposure or extreme temperatures. Broodcells performed higher but still fell short. In contrast, encapsulated spores exhibited ~1,000x greater UV tolerance and were capable of germinate even after exposure to −196 °C for greater than every week or 55 °C for a full month.
Why did the worn-out spores survive the cruel conditions?
The team concluded that every distal surrounding structure absorbs potentially harmful UV light and provides physical and chemical shielding. They suggest that this protective feature could have helped ancient bryophytes, a bunch of plants that include mosses, move from water to land about 500 to 500 million years ago and avoid repeated mass extinctions.
To determine whether these adaptations hold in real space, the researchers sent the sporophytes into orbit.
Mass launch for ISS for real-world trial
In March 2022, tons of of sporophytes traveled to the ISS aboard the Cygnus NG-17 spacecraft. After their arrival, the astronauts planted samples on the station’s exterior, exposing them to space for 283 days. The samples later returned to Earth on SpaceX CRS-16 in January 2023 and were brought back to the lab for evaluation.
“We expected almost zero survival, but the result was the opposite: most of the spores survived,” says Fujita. “We were genuinely surprised by the extraordinary stability of these tiny plant cells.”
Strong survival and a healthy return to Earth
More than 80% of the spores survived your complete journey, and all but 11% of those who survived successfully germinated within the laboratory. Chlorophyll measurements showed normal levels for just about all pigments, aside from a 20% decrease in chlorophyll a, a light-sensitive compound. Despite this reduction, the ovary remained healthy.
“This study shows the amazing resilience of life that has evolved on Earth.”
The team also used their data to construct a mathematical model that estimated how long an egg could last under such conditions. Their calculations suggest a possible survival period of 5,600 days, or about 15 years, although they stress that more data are needed for a firm conclusion.
Implications for all times beyond Earth
The researchers hope the findings support future studies of how extraterrestrial soils can sustain flora and encourage efforts to make use of wetlands in the event of agricultural systems for off-world environments.
“Ultimately, we hope this work opens a new frontier towards building ecosystems in extraterrestrial environments such as the Moon and Mars.” “I hope our mass research will serve as a starting point.”
This work was supported by a DX Scholarship from Hokkaido University, JSPS Kokanee, and the Astronomer Center of the National Institutes of Natural Sciences.