In a major boon to human space travel, new research has proven that the bacteria essential to our long-term health are fully capable of withstanding the rigors associated with rocket launches and microgravity.
The survival of bacteria as they withstand the forces encountered during rocket flights is a significant issue in planning long-term, crewed missions to Mars. One such bacterium, Bacillus subtilis, has been proven to withstand the extremes of acceleration, deceleration, and even short-term microgravity in a first-of-its-kind study by Australian researchers.
Testing Bacteria Survivability
Despite decades of humans safely living aboard space stations for relatively brief periods of time, questions remain about the viability of certain bacteria that balance the body over decades. For their research, the team conducted what they believe to be the first experiments ever to launch bacterial spores high into the air and collect the returned samples, instead of recreating similar conditions inside a lab. This represents an important step in understanding how living organisms respond to the space environment.
“Our research showed an important type of bacteria for our health can withstand rapid gravity changes, acceleration and [deceleration],” said co-author Distinguished Professor Elena Ivanova of RMIT University. “It’s broadened our understanding on the effects of long-term spaceflight on microorganisms that live in our bodies and keep us healthy.
“This means we can design better life support systems for astronauts to keep them healthy during long missions,” Elena added. “Researchers and pharmaceutical companies can also use this data to conduct innovative life science experiments in microgravity.”
Launching the Rocket
The rocket used in the test was a sounding rocket, typically used for research in the upper atmosphere. B. Subtilis was chosen for its hardiness to undergo the journey into the atmosphere, where it faced up to 13 g as the rocket burned through its second stage. Selecting B. subtilis sets an essential benchmark for the upper limit of bacterial survivability in space launch conditions, on which future research can build by testing more delicate strains.
Some 260 kilometers above the ground, the rocket experienced six minutes of weightlessness as the main engine shut off, marking the beginning of a period of microgravity. Ending the serenity of weightlessness, the bacteria then experienced their most extreme forces yet.
Deceleration hit the rocket with an even higher 30 g than it experienced on ascent, while it spun out 220 times per second. Despite the extreme conditions, follow-up testing of the bacteria revealed that they possessed the same structure and growth capabilities as before the test.
Applications On Earth and Beyond
“This research enhances our understanding of how life can endure harsh conditions, providing valuable insights for future missions to Mars and beyond,” said co-author Associate Professor Gail Iles of RMIT. “By ensuring these microbes can endure high acceleration, near-weightlessness and rapid deceleration, we can better support astronauts’ health and develop sustainable life support systems.”
The team also envisions earthbound applications for their bacteria research, increasing understanding of how microorganisms survive in some of the planet’s most extreme and inhospitable regions. Another application for the work could also be in finding new ways to handle antibiotic-resistant bacteria. Despite the promise of their research, the team cautions that such applications of their discoveries remain a long way off.
Additionally, the team sees one final, yet intriguing possibility for their work, having less to do with keeping humans alive in the challenging environments of space and extraterrestrial worlds, but rather in discovering organisms that are already adapted to thrive there.
“Broader knowledge of microbial resilience in harsh environments could also open new possibilities for discovering life on other planets,” Iles said “It could guide the development of more effective life-detection missions, helping us to identify and study microbial life forms that could thrive in environments previously thought to be uninhabitable.”
The paper, “Effects of Extreme Acceleration, Microgravity, and Deceleration on Bacillus subtilis Onboard a Suborbital Space Flight,” appeared in npj Microgravity on October 6, 2025.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.