Moss in Space: Resilient Spores Thrive on ISS for Nine Months

In the realm of space exploration, the quest for sustainable life-support systems is paramount. While Hollywood depicted survival through potato farming in The Martian, scientists are turning their attention to moss, specifically Physcomitrella patens, commonly known as spreading earthmoss. This remarkable plant, recognized for its pioneering role in transforming barren landscapes into fertile ground, has demonstrated an astonishing ability to survive the harsh conditions of space.

Recent research reveals that moss spores can endure a nine-month journey on the exterior of the International Space Station (ISS) and still retain their ability to reproduce upon returning to Earth. Although this plant may not be suitable for human consumption, its resilience could play a crucial role in future space missions. Dr. Tomomichi Fujita from Hokkaido University, who led the study, emphasized the potential of mosses: “While moss may not be on the menu, its resilience offers insights into developing sustainable life-support systems in space. Mosses could help with oxygen generation, humidity control, or even soil formation.”

This is not the first time the extraordinary survival capabilities of moss have been recognized. Moss species have been sent to the ISS before, showcasing their tolerance for extreme environmental conditions on Earth. Notably, the desert moss Syntrichia caninervis has been found to withstand conditions akin to those on Mars during laboratory experiments.

In a study published in the journal iScience, Fujita and his team investigated the survival of three different moss structures in a simulated space environment. They discovered that spores encased within a protective structure called a sporangium exhibited the highest resilience. These spores successfully germinated after being subjected to ultraviolet (UVC) radiation levels exceeding 100,000 joules per square meter.

Further assessments indicated that these encased spores could withstand vacuum conditions, extreme cold, high temperatures, and radiation in a vacuum. Subsequently, the researchers sent these spores to the ISS aboard the Cygnus NG-17 spacecraft, where they were affixed to the station's exterior in sample holders equipped with varying filter settings. After nine months in space, the samples were returned to Earth for analysis.

Upon examination, all the samples demonstrated impressive germination rates. Notably, even those spores that had been fully exposed to the harsh UV radiation of space achieved an 86% germination rate, compared to a 97% rate for spores that remained on Earth. However, the researchers noted that a certain type of chlorophyll in the space-exposed samples exhibited signs of degradation.

Dr. Fujita remarked, “If such spores can endure long-term exposure during interplanetary travel and then successfully revive upon rehydration and warming, they could one day contribute to establishing basic ecosystems beyond Earth.” He also noted that this study concentrated solely on the survival of moss under space exposure, leaving the question open as to whether moss can germinate and thrive in various extraterrestrial environments, including differing gravity levels, atmospheric compositions, and radiation intensities.

Dr. Agata Zupanska from the Seti Institute, who was not involved in this research, welcomed the findings. She acknowledged that while the resilience of moss is already known, this study provides valuable insights into its potential applications in space biology.

The findings about moss's survival on the ISS offer a promising glimpse into the future of space exploration. As scientists continue to explore the possibilities of using moss and other resilient organisms to create sustainable life-support systems, the dream of establishing ecosystems beyond Earth moves closer to reality. With ongoing research, the role of mosses in future interplanetary habitats could be pivotal in ensuring the survival of human life in the vast expanses of space.