Scientists prove human gut bacteria can survive space travel without us

Space travel is not for the weak. Astronauts suffer from motion sickness, disorientation and cardiovascular stress even before reaching orbit. Fortunately, the bacteria that live inside us are much more resistant. A new study shows that a gut bacteria essential to human health can survive the stress of launching into space aboard a rocket, the microgravity environment and re-entry into Earth’s atmosphere.

A group of Australian scientists launched spores of Bacillus subtilis, a Gram-positive bacteria that lives in our intestinal tract, to the edge of space to see how the microbes behaved. Upon examination after the bacteria returned to Earth, scientists found that the microbes had undergone no changes in their ability to grow and their structure remained intact.

The results are detailed in a study published Monday in npj Microgravity. The work indicates that the bacteria would likely function as needed in the intestines of any human en route to Mars – crucial information for astronauts’ health. But it also suggests that contamination of Mars by terrestrial bacteria of human origin may be inevitable.

Space bacteria

Previous experiments aboard the International Space Station (ISS) have shown that certain types of bacteria can survive in space. However, little research has been done on the effects of rocket launch and reentry on the survival rates of human gut bacteria.

To test the bacteria, researchers packed spores aboard a sounding rocket and launched it to an altitude of about 260 kilometers above the Earth’s surface. During the second stage burn, the rocket experienced a maximum acceleration of 13 G (13 times the force of Earth’s gravity).

Once the desired altitude was reached, the researchers began a brief period of weightlessness that lasted about six minutes, with the main engine shutting down. After that, the rocket began its descent toward Earth, decelerating with forces of up to 30 G while rotating at a speed of 220 times per second.

After the grueling trip, the researchers examined the bacterial spores to see how they behaved during the rocket’s launch and reentry. Surprisingly, the bacteria showed no change in its structure nor did the extreme forces affect its ability to grow.

“Our research has shown that a type of bacteria important to our health can withstand rapid changes in gravity, accelerations and decelerations,” Elena Ivanova, a professor at the Royal Melbourne Institute of Technology in Australia and co-author of the study, said in a statement. “This has expanded our understanding of the effects of long-term spaceflight on the 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.”

However, the idea of ​​bacteria surviving and thriving en route to the Red Planet doesn’t always spark enthusiasm. The findings follow a separate study published last year that warned that bacteria not only had the potential to survive a trip to Mars, but also felt at home in Martian soil. As space agencies plan human missions to Mars, there is growing concern that these missions could contaminate the Martian environment without Earth microbes. This could lead to erroneous discoveries of life on the planet, but it could also pose an immediate risk to the astronauts themselves – or even to any life that might be on Mars in the first place.