Cape Canaveral (United States) (AFP)

NASA is launching its Perseverance mobile robot to Mars on Thursday, designed to uncover traces of ancient microbes that may have swarmed the planet three billion years ago. The rover also carries a mini-helicopter which will attempt the first flight of an aircraft on another planet.

The United Launch Alliance Atlas V rocket launch is scheduled for 07:50 (11:50 GMT) from Cape Canaveral, Florida.

If it arrives intact on February 18, 2021, Perseverance will be only the fifth rover to make the trip since 1997. All are Americans.

China launched its first Martian rover last week, which should land in May 2021. Mars could therefore have three rovers in operation next year, with the American Curiosity, which has traveled 23 km on the red planet since 2012.

- Helicopter on board -

The new rover, built at the legendary NASA Jet Propulsion Laboratory in Pasadena, California, is an improved version of Curiosity: its six wheels are more robust, it is faster, smarter and can be self-piloted over 200 meters by day.

As big as a 4x4 (three meters long), it weighs a ton, has 19 cameras and two microphones, which could be the first to record Martian sound. Its robotic arm measures two meters. A plutonium generator will recharge its batteries.

Once safely, NASA will attempt to take off the Ingenuity helicopter, 1.8 kg, in the very fine air of Mars, dense as 1% of the Earth's atmosphere. The aim is to prove the feasibility of the concept.

NASA is very interested in planetary exploration from the air, because rovers can only travel a few tens of kilometers in their life, and are vulnerable to sand dunes and other reliefs, although Perseverance will be able to climb obstacles 40 high. cm. A first flying drone (Dragonfly) will be sent in 2026 to Titan, Saturn's largest moon.

Perseverance's main mission will be to search for traces of past life on Mars, as scientists believe they have good evidence that over three billion years ago the planet was warmer and covered with rivers and lakes, ingredients that gave birth, at least on Earth, to microbes ... Before the red planet became cold and dry, for a reason that still eludes planetologists.

Another first: Perseverance will take around thirty rock samples in tubes, which a future American-European mission will recover to be brought back to Earth, no earlier than 2031.

The indisputable proof of past life on Mars will most likely not be confirmed, if it exists, until these samples are analyzed next decade, Thomas Zurbuchen, NASA chief scientist, said Tuesday.

- What a life? -

"We are probably looking for a very primitive life form, not advanced forms like bones or fern fossils," said Ken Farley, project scientist at Caltech University.

NASA chose to land in the 3.8 billion-year-old Jezero crater, specifically in what strongly resembles an ancient delta.

Deltas are formed when rivers deposit sediment in a body of water. "Deltas are great places to preserve organics and other types of biosignatures," says Tanja Bosak of MIT and member of the science team.

The advantage of Mars, unlike Earth, is that the crust is not constantly being renewed by plate tectonics. On Earth, it is extremely difficult to find land untouched for three billion years.

"Mars preserves an incredibly complex and diverse geology on its surface," said Lori Glaze, head of NASA's planetary exploration programs. The whole history of Mars remains etched on the surface.

More than 350 geologists, geochemists, astrobiologists, atmospheric specialists and other scientists from around the world are taking part in the mission, which will last at least two years, and probably much longer if the experience of the people is to be believed. previous rovers, very enduring.

© 2020 AFP