New evidence from an Australian-led study shows Bacillus subtilis spores can endure the harsh dynamics of spaceflight
As space agencies outline bold plans to send crews to Mars within decades, scientists are racing to understand how living organisms cope with the extreme conditions of space travel. A recent Australian-led study provides a critical clue: the spores of Bacillus subtilis, a bacterium linked to human health, can survive rapid acceleration, short bursts of microgravity, and rapid deceleration during re-entry.
The research, which marks one of the first attempts to test bacterial resilience in real-world spaceflight conditions outside the traditional lab, involved launching spores high into the atmosphere and analyzing them after their rocket returned to Earth. The team’s aim was to simulate the flight profile that future crewed missions might experience, while isolating the survivability factors that could affect human health on long journeys.
“Our research showed an important type of bacteria for our health can withstand rapid gravity changes, acceleration and deceleration,” said Distinguished Professor Elena Ivanova from RMIT University, a co-author of the study. “It’s broadened our understanding on the effects of long-term spaceflight on microorganisms that live in our bodies and keep us healthy.”
The findings have multiple implications for space exploration. First, they enhance our understanding of how beneficial microbes behave in space, which is crucial for maintaining crew health over extended missions. Bacillus subtilis is known to contribute to digestion, immune support, and cardiovascular health in humans, making its stability under spaceflight conditions particularly relevant for life support systems that keep astronauts healthy on journeys to Mars.
Secondly, the study offers valuable data for designing life support architectures that rely on microbial processes. If hardy bacteria persist through the most intense phases of launch and re-entry, engineers and life-support researchers can adjust systems to work with, rather than against, microbial actors. This could involve optimizing bioreactors for air and water recycling or tailoring probiotic strategies to preserve the astronauts’ microbiome during transit.
While human crews on space stations have lived in orbit since the 1970s, the long-duration, deep-space missions envisioned for a Mars expedition present a different set of challenges. The current work underscores that certain microorganisms integral to human health can endure the mechanical and environmental stresses of ascent and re-entry, which are not fully captured by conventional laboratory simulations. Researchers hope to expand this line of inquiry to include a broader range of microbes and more complex simulants of spacecraft life-support systems.
The study’s insights also carry implications for pharmaceutical and life-science experiments conducted in microgravity. By understanding which microorganisms survive under high-stress conditions, scientists can design experiments that probe microbial biology in space with greater precision and safety. In turn, this knowledge could accelerate the development of therapies and health-maintenance strategies tailored to space travelers.
Looking ahead, the researchers emphasize the need for continued, real-world testing of microbes in space-like conditions. As humanity plans for durable off-world living, the resilience of Bacillus subtilis reminds us that the microscopic inhabitants of the human body will play a pivotal role in keeping astronauts healthy, resilient, and capable of thriving on a distant world. The findings from these early experiments lay a foundation for future studies that will refine how we protect and nurture human life as we push further into the solar system.
