“We are definitely in the right place.” The researchers are now confident that they have sent the vehicle to the location that offers the best possible chance of finding traces of life on the red planet.
“Percy”, as the robot affectionately called, landed in the crater de Jezero in February 2021 and, since then, has taken thousands of photos of the surroundings of the area. The interpretation of these images is the basis of the first scientific article based on these discoveries, published this week in the journal Science.
The analysis confirmed that Perseverance is where it once was the bottom of a large lake on the Martian surface, by a meandering river that reached a fed depression to the west. We’re talking about what happened more than 3 something, 5 billion years ago, when the climate of Mars was more like that of Earth.
From Perseverance’s observations, it was possible to find out Where the river joined the lake, the flow suddenly slowed and the suspended sediments eventually precipitated out, forming a delta. It is a wedge-shaped formation that can also be seen in many places on Earth.
It was in this environment that some microorganisms may have proliferated and perhaps left traces that would still be preserved today.
Professor Sanjeev Gupta, Imperial College London, co-author of the Science article, comments: “Some people said to me: ‘What’s new in this? We didn’t already know there was a delta in the crater of Jezero?’ Well, actually, we didn’t know. We identified from orbital images that Jezero contained a delta, but until you’re on the ground you can’t be absolutely sure. We might be looking at an alluvial fan.”
An alluvial fan or dejection cone is a geological formation in which, in general, a fan of materials is deposited in a much more energetic environment, such as a sea or a river. Martian microbes, if they existed, would have preferred the calmer, more permanent waters of a delta.
Perseverance landed about 2 km from the main delta, but the images captured by its telescope are more interesting, especially when it’s located in an isolated mound the scientists dubbed Kodiak.
” It is possible to see in these remains some stratification that would normally produce a developing delta.”
There are horizontal bottoms formed by fine granular sediments that the river has thrown from its entrance to the lake in the crater. Above them appear the sediments that have descended the slope through the most advanced lobes of the delta. And higher still are the sediments that were deposited by the river after the delta’s banks expanded.
In addition to the Kodiak and the formation of the main delta, Jezero has many large cliffs. This indicates the existence of flooding at later times in the crater’s history.
“Something has changed in hydrology. We don’t know if it was a climate-related event, we don’t,” says Professor Gupta. “To move such large rocks, you need something like a flood. Perhaps there were glacial lakes in the local basin that sent these streams of water toward Jezero.”
“We see lake overflows on Earth , in places like the Himalayas. In the Ganges basin, you have these big rocks mixed into the normal sand of the river and where there was a sudden flood of a glacial lake,” said Gupta BBC News.
A Perseverance’s scientific team sends him to the base of the main delta formation to drill through the ground in search of the small clay boulders they hope to find. They will also focus on a ring of limestone rocks around the rim of Jezero, which possibly represents the crater’s margins in its deepest lake era.
The robot has a mission to collect and store more than two dozen rock samples from different locations. These samples will be brought back to Earth in early 2030 to be examined in laboratories able to determine if there were any microscopic life forms on the surface of Mars.
Plans for this are in place well advanced and will involve sending another robot from NASA and its European Space Agency partners to retrieve the samples from the crater point where Perseverance stores them.
To be a British-made vehicle. He will collect the rocks and transfer them to a rocket that will launch them towards a point in the orbit of Mars, where a satellite will be waiting to finally transport them to Earth.
“We are about to enter the most exciting moment of Mars exploration,” says Sue Horne, head of space exploration at the UK Space Agency. “With the sampling vehicle’s propulsion system being tested in the next month, the dream of examining specimens from the planet will soon become a red reality.”