On target ! By choosing Jezero crater for the rover’s perilous arrival on Mars
Perseverance on February 18, 2021, NASA and all the researchers collaborating on this mission hoped to target, on the basis of satellite images, an ancient lake area suitable for the search for traces of life. The very first results transmitted by the Martian robot, and unveiled Thursday in the review Science, confirm that they had flair: the crater owes its shape to a huge expanse of water “about 35 km in diameter” and dating back 3.6 billion years.
This certainty was established thanks to the images transmitted by SuperCam, the hyper-sophisticated instrument built in Toulouse and which serves as the rover’s homing head. Thanks to him, Perseverance was able to observe details “of less than 10 centimeters” while standing 2 km away from the area of interest to the specialists. And, according to the study, led by Nicolas Mangold, CNRS geologist from the planetology and geodynamics laboratory, “the inclined sedimentary strata, sandwiched between horizontal strata” found in Jezero do indeed have a geometry “typical of deltas on Earth” .
“We are in the right place”
“We expected this pleasant surprise a little, there we are reassured”, reacts Sylvestre Maurice, astronomer at the Institute for Research in Astrophysics and Planetology of Toulouse (Irap), the cradle of SuperCam. “We now know that we are in the right place and that it is conducive to looking for traces of life there,” enthuses the researcher. Clay and sandy sediments are indeed “very good candidates” for finding any organic matter.
The images also revealed large pebbles and large boulders one meter across, witnesses to “strong river currents” and probably “major climate change” whose nature has yet to be determined. The large boulders could also provide “fragments of Martian crust”.
Jezero will only reveal its ultimate secrets when the samples – sediment or crust – will be analyzed on Earth… by 2030. “SuperCam will continue to document its environment and the geological context. This will make it possible to select the most interesting samples which will have to be recovered by the mission which will arrive on Mars around 2026 ”, explains Sylvestre Maurice.
For the anecdote, this “lake of promises” is unveiled in full “solar conjunction” of Mars, this period of approximately two weeks, which returns every two years, and during which the sun intervenes between the Red Planet and the Earth, making all communication impossible with Martian instruments.