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NASA's Mars 2020 rover, with its extended robotic arm, in an artistic rendering of 2017. (NASA / JPL-Caltech)
In search of ancient life on Mars, NASA will send its next rover to explore the Jezero crater, site of an ancient delta and lake.
The rover, scheduled for launch in 2020, is equipped with a drilling system capable of collecting and storing rock samples containing clues about Mars' ancient past. Once the samples are cached, NASA hopes to send follow-up missions to retrieve the samples and send them back to Earth.
"Getting samples of this lake-delta system will revolutionize our understanding of Mars and its ability to shelter life," said Thomas Zurbuchen, deputy administrator of science at NASA.
The selection of the landing site came after years of research and days of fierce debate about the best place to look for evidence of ancient life in an extraterrestrial world. Alternatives include Columbia Hills, an ancient source of hot water explored by the now-defunct Rover Spirit, and Northeast Syrtis, a network of ancient mesas that may have harbored groundwater. .
In the end, Zurbuchen said that Jezero was selected for the diversity of his field. Each type of rock present on the site – clays likely to preserve the signs of ancient organisms to volcanic rocks evoking the evolution of the planet on Mars – should allow the rover to reach its two main scientific objectives. First, to determine what the environment of the red planet looked like in the past. And secondly, to find out if life ever happened there.
The results of previous missions revealed that Mars was not always the desert and sorry world we see today. Sleeping volcanoes suggest that it has already had intense volcanic activity. And reliefs such as the dry delta of the Jezero crater show that liquid water existed on the surface – which means that Mars may have a thicker atmosphere that prevented the water from evaporating.
This new vision of Mars resembles what we know on the primitive Earth. And scientists know that microbial life started here 4 billion years ago.
If it happened here, why not here?
The crater of Jezero is the site of an ancient delta that has entered a lake of craters.
Mudstones formed from sediment slowly dumped into the lake may contain carbonates and even biological remains (if biology has ever existed).
But the windswept sand formations known as "wrinkles" are a danger to the rover here and on other sites.
Mudstones formed from sediment slowly dumped into the lake may contain carbonates and even biological remains (if biology has ever existed).
But the windswept sand formations known as "wrinkles" are a danger to the rover here and on other sites.
Mudstones formed from sediment slowly dumped into the lake may contain carbonates and even biological remains (if biology has ever existed).
But the windswept sand formations known as "wrinkles" are a danger to the rover here and on other sites.
Mudstones formed from sediment slowly dumped into the lake may contain carbonates and even biological remains (if biology has ever existed).
But the windswept sand formations known as "wrinkles" are a danger to the rover here and on other sites.
The Washington Post
Source: NASA / JPL / University of Arizona
Jezero Crater is the best place on Mars to probe the issue, said Tim Goudge, a geologist at the University of Texas at Austin, who is one of the site's leading advocates. Scientists love deltas because of the way they collect sediments from a watershed and deposit them in layers, which eventually harden into rocks. Most of the oldest fossils found on Earth come from this type of environment.
If a microbe swims in the waterways of Mars, its organic remains could still be buried in the mudstones along the rim of the crater of Jezero.
"Sedimentary rocks tell us the story of what happens on a site," said Goudge. "It's saved in layers and you can read them as a book."
In a note announcing his selection, Zurbuchen pointed out that Jezero offered exploration opportunities after its initial mission, which will last a year and a half Martian (or about 2.8 terrestrial years). The crater is not far from an area known as Midway, which shares many features with northeastern Syrtis. At a recent workshop to assess potential landing sites, members of the project's scientific team for March 2020 said that an extended mission linking Jezero to Midway could allow scientists to explore the best of both sites.
The Jezero crater is a more dangerous environment than NASA usually lands. Landers often have to come up with what scientists jokingly call "parking" – a flat, flat area – and then travel long distances to reach the rocks. interest. However, an innovative new technology called Ground Navigation (TRN), which allows the spacecraft to compare images from the landscape below it to a known hazard map, should allow the vehicle to all security.
As TRN has never been deployed before, Zurbuchen has asked engineers to provide him with additional analysis of the technology. Without the assurance that the technology will work as expected, the complex environment of Jezero could pose a risk of landing too high. But Zurbuchen is satisfied with the progress made so far by TRN.
Read more:
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