AFP, published Thursday, September 15, 2022 at 10:32 pm
The Perseverance rover has reached a milestone in its search for traces of ancient life on Mars with the collection of the “most valuable” samples to date, containing potential bio-signatures whose nature will need to be confirmed once on Earth, NASA announced Thursday.
If this is not yet proof that life once existed on the red planet, these samples thus far represent the best chance of one day being able to detect with certainty a possible ancient microbial life.
A potential bio-signature may have been produced by the presence of life, but also by some other mechanism that does not involve life. To consider this bio-signature as definitive, these samples will therefore have to be analyzed by powerful laboratory instruments on Earth. NASA plans to bring them back on another mission by 2033.
“I think it’s safe to say that these will be, and already are, the most valuable rock samples ever collected,” David Shuster, of the University of California at Berkeley.
Two carrots the size of a little finger, and kept in sealed tubes aboard the rover, were taken by drilling into a rock called “wildcat crest”. About one meter high, it is located in a delta formed about 3.5 billion years ago, where a river and an ancient lake meet.
This rock is particularly interesting because it is a sedimentary rock, which appears to have formed when the water in the lake evaporated.
“Wildcat ridge” therefore has “a high potential for bio-signature retention,” said David Shuster.
Analyzed separately by an instrument at the end of Perseverance’s robotic arm, the rock revealed the most abundant presence of organic compounds detected in a year and a half mission.
These compounds – consisting in particular of carbon, and which may also contain hydrogen – “are the building blocks of life,” said Ken Farley, head of the scientific part of the mission.
They have been detected in smaller numbers by the rover during previous analyzes in the Jezero crater, which contained the lake, but “as we advance into the delta, the clues get stronger,” Sunanda summarized. Sharma, a NASA scientist Jet Propulsion Laboratory.
“Personally I find these results very moving, because it seems that we are in the right place, with the right tools, at a crucial moment,” he said.
“These rocks are exactly what we came for,” said Ken Farley.
– “Lava lake” –
Other analyzes of the rover also surprised the scientists. At the bottom of the crater, they “found igneous rocks, that is, rocks that crystallized after melting,” Farley said.
This finding indicates “active volcanism” and that before receiving water, the crater may have been filled with “a lava lake,” he said.
Samples of these igneous rocks have been collected and their analysis on Earth should allow for the first time to directly determine the age of the surface of Mars. “It’s something we’re only indirectly deducing today,” explained Ken Farley.
But getting those samples won’t be easy.
In 2028, a mission to Mars will take off. It will carry a lander, with a mini-rocket on its back. The Perseverance rover will approach it and the samples will be inserted into the mini-rocket by a robotic arm.
It will then take off and the precious cargo will be transferred to a ship previously placed in orbit around Mars. Once the samples are collected, this orbiter will return to Earth for a landing in the Utah desert in 2033.
If Perseverance fails, the lander will send two small helicopters to collect the samples, either going to the rover itself or to a reserve reserve.
In fact, Perseverance has collected two samples of each rock since the beginning of its mission. A dozen of them (half the number collected) will soon be deposited in a very flat area, where it will be easy to land if necessary. They represent backup champions if it becomes impossible to access the rover.
After leaving this treasure on the Martian surface, Perseverance will continue its exploration over the next few weeks to fill the approximately twenty still empty tubes.
The next goal will be to reach the shore overlooking the old lake, which will last about a year.