Will humanity one day be able to live on Mars? This question has tormented scientists for decades. A recent experience, however, reminds us to what extent the red planet remains hostile to living things. Researchers at Pennsylvania State University exposed tardigrades, the famously extremely tough microscopic creatures, to a sample of simulated Martian soil. Verdict: the little creatures slowed down their movements before coming to a complete standstill.
However, everything is not to be thrown away in this experiment with paradoxical results. After the astronomers added a little water to the artificial soil, the tardigrades began to move again, including those that had been exposed to it for several days. This indicates that a still unidentified substance would make the soil hostile to biological life, but would lose its effects after rinsing.
Since the beginning of space exploration, scientists have adopted strict protocols to prevent probes and other spacecraft from contaminating their environment with terrestrial organisms. “When considering sending humans to other planets, we need to understand two things: how the environment will affect humans and how humans will affect the environment», Underlines in the columns of The Debrief Corien Bakermans, professor of microbiology at Pennsylvania State University.
According to her, Martian soil probably has a property capable of inhibiting all forms of life. The challenge now is to understand how to neutralize this effect, in order to reduce the risks for future explorers.
Tardigrades, survivors of the extreme
The choice of tardigrades in this experiment was carefully considered. Their ability to withstand freezing temperatures or long periods without food has made them ideal candidates for assessing the possibilities of survival on Mars. However, this is not the first time that these organisms have transformed into statues in the face of a particular environment. When they are dehydrated or exposed to difficult conditions – space vacuum, extreme pressures of the ocean depths – they enter a dormant state, close to the absence of life. Rehydrated, they return to their normal activity.
The team of researchers believes that the substance “very damaging» present in the soil could be dissolved in water or eliminated with salt. A discovery that could weigh heavily in future Martian colonization projects. “Regolith’s defense mechanism could stop contaminantsspecifies the professor. At the same time, it can be washed to promote plant growth or prevent damage to people who come into contact with it.”
There remains a major problem: water is a rare resource during space missions. It is difficult, in these conditions, to imagine a large-scale clean-up. However, American scientists have not said their last word: the team is now interested in other parameters likely to inhibit biological activity, notably temperature or atmospheric pressure, in order to better understand the red planet.
“Regolith is obviously not the only factorspecifies Corien Bakermans. We are beginning to distinguish the different components of this system, in which each element can represent either an obstacle or an advantage. The path before an astronaut sets foot permanently on Mars remains long and strewn with pitfalls, but each experience sheds light on its contours a little more.
