Spaceflight tests reveal hardy microbes vital for astronaut health
Microbes essential for human health have proved remarkably resilient against the extreme forces of space travel. In a pioneering experiment, researchers tested the well-known gut and immune-supporting bacterium Bacillus subtilis by sending its spores on a sounding rocket flight. The goal: to understand how such microorganisms would endure the launch, brief microgravity, and the brutal stresses of reentry as humanity paves the way for long-duration missions beyond Earth.
What was tested and how
Scientists from the Royal Melbourne Institute of Technology (RMIT) in Australia placed Bacillus subtilis spores in a 3D-printed microtube holder and launched them on a sounding rocket. During the flight, the samples faced accelerations up to 13 g, about six minutes of near-weightlessness at roughly 162 miles (260 kilometers) altitude, and decelerations reaching 30 g during descent, with the capsule spinning about 220 times per second. Such conditions simulate, on a smaller scale, the stresses astronauts experience during a real space mission.
Why Bacillus subtilis matters for space health
Bacillus subtilis is known to support human health by aiding gut function, modulating the immune system, and improving blood circulation. If these spores can maintain integrity and viability through the harsh phases of spaceflight, they could be crucial in sustaining the astronauts’ microbiome during long journeys, including missions to the Moon, Mars, and beyond.
Key findings and implications
Post-recovery analyses showed that the spores preserved their structural integrity and grew as they would on Earth. This finding, reported by the research team, indicates that certain beneficial microbes can withstand rapid gravity changes, accelerations, and deaccelerations. The study provides a real-world benchmark for how microbes behave under the full spectrum of rocket flight stresses, not just laboratory simulations.
Dr. Elena Ivanova, a co-author from RMIT, emphasized the broader significance: resilient microbes could inform the design of life support systems for space habitats, enabling reliable waste recycling, food production, and plant growth. A healthy microbiome is linked to digestion, immunity, and overall well-being—areas that become increasingly critical on prolonged missions where resupply from Earth is limited.
Looking ahead: life support and beyond
The experiment represents the first effort to test bacteria under authentic spaceflight conditions outside controlled lab environments. Beyond confirming microbial resilience, the work lays groundwork for integrating robust microorganisms into closed-loop life support systems. Such systems would support astronauts by recycling waste, producing nutrients, and sustaining healthy environments in spacecraft and off-world bases.
While Bacillus subtilis spores are notably hardy, the study also serves as a springboard for evaluating other health-linked microbes used in human care and agriculture. Researchers envision a future in which a carefully curated microbiome is transported alongside crews, helping to regulate digestion, immunity, and even mood—key components of mission success on long-duration expeditions.
Earth benefits and the search for life
Understanding microbial resilience in extreme environments has terrestrial value as well. Insights into how microbes withstand rapid environmental changes could spur new antibacterial strategies, inform treatments for antibiotic resistance, and guide life-detection missions on planets and moons where conditions may initially seem hostile to life. Ivanova notes that the findings could aid in recognizing microbial life that thrives in environments once deemed uninhabitable, sharpening astrobiological search efforts.
Bottom line
The resilience of Bacillus subtilis spores under rocket flight stresses offers a hopeful glimpse into the future of human space exploration. If essential microbes remain viable through launch, microgravity, and reentry, astronauts could benefit from more stable microbiomes, robust life support systems, and healthier, more sustainable long-duration missions.
