Mars: what are the risks of a delivery of extraterrestrial matter to Earth?

Ever since Perseverance began collecting rock samples from the surface of Mars, scientists have had only one thing on their mind: bringing that extraterrestrial dust back to Earth. A technological challenge. But a challenge also in terms of protection. Because, what would happen if a form of life were hiding in these samples and found its way to us?

In February 2021, the NASA rover Perseverance landed on Mars. His mission: to look for traces of life on the red planet. Traces that could be hiding in the rock samples he is responsible for collecting. A first sampling took place last September. The sample was stored in the hermetic box provided for this purpose. Seven others have already experienced the same fate. Waiting to be picked up by another mission. Then brought back to Earth to be analyzed in detail.

And it is precisely this last point that raises questions today. How the Nasa does it intend to protect our planet from possible germs Martians embarked on the journey? Because even if the probability that the life exists on mars is low, it is not zero.

The plan is the following. Be careful, it is a bit complicated. Because it requires the intervention of several machines. First, a sample return probe to Earth — provided by the European Space Agency (ESA) — called Earth Return Orbiter. It should be launched in 2027. Then, a recovery rover, the Mars Fetch Rover — still provided by ESA –, and its landing platform which should be ready to leave for Mars in 2028. Finally, a sort of rocket martian, the Mars Ascient Vehicle, which would also take off in 2028. The idea, therefore, is for the rover to recover the sealed samples. Samples launched with the rocket to join theorbit Of March. Everything would then be recovered by the return probe.

A real risk of contamination

In operation, it is intended that the sample container be heat sterilized. At nearly 500°C. To eliminate, at least on the container, any possible biomolecule that could present any danger. Preserving, despite everything intact, the samples of rock that is inside. The operation looks delicate.

Then NASA engineers plan to retrieve the whole thing somewhere in the desert of Utah (USA). But voices are already rising. That of the International Committee Against the Return of Samples from Mars, for example. How to ensure that after a crash at almost 150 km/h, the sample container will not be damaged? What would happen then if organisms pathogens Martians found themselves free to propagate on Earth?

The scientists who have worked on the question have their idea. According to them, whatever life forms might exist on Mars would certainly be ill-suited to life on Earth. To life in a completely different environment. Assuming that life really exists today on Mars… What the experts judge “highly unlikely”.

Despite everything, scientists expect “take a position of protection of the Earth”at least until we know “what’s out there”. But ultimately, the real danger would rather be that of a contamination valuable Martian samples with terrestrial material. As if the billions of dollars invested went up in smoke. So even if the scientists expect some reluctance from the public, especially after the Covid-19 pandemic that we have experienced, they remain impatient. After having “looked at this world through the eyes of robots»they hope to finally be able to see with their own eyes “that famous red dust”.