French scientists thrilled at latest Mars landing

Geologists in southeast France among those are eagerly watching as Nasa's latest €2.44billion mission to Mars begins its difficult automated landing sequence.

The Mars Perseverance rover has to perform the entire seven-minute landing sequence on its own, from atmospheric entry and parachute release to a rocket-powered hover as the rover is lowered to the Martian surface, because the sequence takes place faster than a signal could reach Earth from Mars.

Perseverance is the second rover, after Curiosity, to attempt this style of entry into the Martian atmosphere. The entire landing will be broadcast on the CNRS Youtube site.

Once it lands, it will begins a Martian year-long mission (670 days) to sift and drill into the sediments to look for traces of ancient microbial activity.

The most promising examples will be carefully stored in tubes which - it is hoped - will be collected and returned to Earth by later missions.

The intention is that shortly before 22:00 on Thursday, February 18, the rover will land safely in the 45km wide Jezero crater, which - 3.5billion years ago - was filled with liquid water. It is hoped the rover will be able to collect and analyse samples containing the fossilised remains of Martian life.

The site was selected following extensive analysis by geologists at University Lyon 1 of data from the last four Mars exploration missions as part of a European Research Council-sponsored project.

Geologists chose the landing site - selected because it was once filled with water, and also because it is believed that old clay deposits, usually a metre or so below the planet's surface, are close to or on the surface because of wind erosion.

The entire crater has multiple rock types, including clays and carbonates, that have the potential to preserve the type of organic molecules that would hint that life once existed there. The ancient shoreline is of particular interest.

“It's a question of chronology: no Martian exploration mission has yet focused on the period 4 billion years ago, which is that of clays,” Cathy Quantin- Nataf, who led the university's team that found the site, said.

“Given the amount of clay in Martian soil, we can imagine that something important happened 4 billion years ago for the future of life on this planet.”

"This is the first step, that of returning Martian samples. This is something we have awaited for years because we study Mars a lot. First with telescopes, then probes, but we would like to have Martian rocks in our hands," said the French university's Erwin Dehouck.

As well as choosing the landing site, French scientists have developed one of seven dedicated instruments on board the rover. 'SuperCam' will use lasers to analyse the chemical composition of rocks and could detect the presence of organic molecules.