One of the potential problems that the exploration of mars for humanity is that certain bacteria strains they can survive despite the harsh environment of the “red planet” and future astronauts and space tourists could inadvertently contaminate Mars, but they could also bring new diseases to Earth.
“Our model organisms serve as indicators of direct contamination of Mars and reverse contamination of Earth, which should be avoided,” says Michael Daly, Professor of Pathology at the Uniformed Services University of the Health Sciences (USU) and a member of the Committee. of Planetary Protection of the National Academies, which led the study.
These are the conclusions of a new study published in Astrobiology in which the harsh conditions of ionizing radiation on Mars were simulated to see how long dry and frozen terrestrial bacteria and fungi could survive.
In this unpublished study, a team of researchers, including Brian Hoffman and Ajay Sharma of Northwestern University, USA, further commented that “we concluded that terrestrial contamination on Mars would be essentially permanent.” , over periods of thousands of years. This could complicate scientific efforts to search for Martian life. Likewise, if microbes evolved on Mars, they might be able to survive to the present day. That means returning samples from Mars could contaminate Earth.”
But specifically, there is a terrestrial bacterium that could survive the Martian environment, it is ‘Deinococcus radiodurans’ (affectionately known as ‘Conan the Bacteria’). In the experiments, it survived astronomical amounts of radiation in a cold and arid environment, surpassing with you grow Bacillus spores, which can survive on Earth for millions of years.
This is especially due to the amount of manganese antioxidants that would help them resist high doses of radiation.
The researchers found that the Conan bacterium, when suspended in liquid, can survive 25,000 radiation (or “gray”) units, the equivalent of about 1.2 million years just below the surface of Mars. But the new study found that when the abundant bacteria dries out, freezes and burrows deep, which would be typical of a Martian environment, it could withstand 140,000 grays of radiation. This dose is 28,000 times higher than that which would kill a human being.
Although the Conan bacterium could only survive for a few hours on the surface while bathed in ultraviolet light, its lifespan improves dramatically when it is in the shade or directly below the surface of Mars. Buried just 10 centimeters below the Martian surface, the survival period increases to 1.5 million years.