“We are definitely in the right place.”
There is a sense of relief in the science team responsible for the Perseverance (Persevere, in Portuguese) Exploration Rover that NASA has on Mars.
The researchers are now confident that they have sent the car to the location that offers the best possible chance of finding traces of life on the Red Planet.
“Percy,” as the robot is affectionately called, landed at Jezero Crater in February 2021 and has since taken thousands of photos of the surrounding area.
Interpreting these images is the basis for the first scientific article based on these findings, published this week in the journal Science.
The analysis confirmed that perseverance is where it was once the bottom of a large lake on Mars, fed by a meandering river that reached a depression to the west. We are talking about something that happened more than 3.5 billion years ago, when the climate of Mars was more like that of Earth.
From the observations of perseverance, it was possible to discover that at the place where the river meets the lake, the flow suddenly decreased and the suspended sediments were eventually deposited, forming a delta. This is a wedge-shaped formation that you can also see in many places on Earth.
In this environment, some microorganisms may have multiplied and may have left traces that are still preserved today.
Professor Sanjeev Gupta of Imperial College London, co-author of the science paper, comments: “Some people have said to me, ‘What’s new in this? Didn’t we already know there was a delta in Jezero crater? Well, actually, we didn’t know, we determined from orbital images that Jezero had a delta, but until you’re on Earth you can’t be completely sure.
An alluvial fan or gloom cone is a geological formation in which, in general, a fan of material is deposited into an environment with much more energy, such as a sea or river.
If Martian microbes were present, they would have preferred the calmer, more continuous waters of the Delta.
Perseverance landed about two kilometers from the main delta, but the images taken with its telescope are more interesting, especially when it is located on an isolated hill that scientists named Kodiak.
“It is possible to see in these remnants some stratification that normally produces developing deltas.”
There are horizontal bottoms consisting of fine granular sediments thrown out by the river from its entrance to the lake in the crater. Above them are the sediments that descended the slope through the more advanced deltaic lobes. Even higher, the sediments deposited by the river after the expansion of the banks of the delta remains.
In addition to the Kodiak and the main delta formation, Jezero has many large cliffs. This indicates that there was a flood at times later than the crater’s history.
“Something has changed in the hydrology. We don’t know if it was a climate-related event, we don’t know,” says Professor Gupta. “To move rocks of this size, you need something like a flood. There were probably glacial lakes in the local basin that sent these water currents toward Jezero.”
“We see a lake flooding on the ground, in places like the Himalayas. In the Ganges basin, these big rocks mix into the natural river sand, and here there was a sudden flood of a glacial lake,” Gupta told BBC News.
The Perseverance Science team will send you to the base of the main delta formation to dig into the ground for the tiny mud rocks they hope to find. They will also focus on a ring of limestone around the edge of Jezero, which probably represents the shores of crater lake at its deepest.
The robot is tasked with collecting and storing more than twenty rock samples from different locations. These samples will be returned to Earth in the early 2030s for examination in laboratories capable of determining whether microscopic life forms exist on Mars.
Plans for this are in progress and will involve sending another robot from NASA and its partners from the European Space Agency to retrieve samples from the crater spot where Perseverance stores them.
It will be a British-made vehicle. It will collect rocks and transfer them to a rocket that will launch them toward a point in Mars’ orbit, where it will wait for a satellite to finally transfer them to Earth.
“We are on the cusp of one of the most exciting moments in Mars exploration,” says Sue Horn, head of space exploration at the British Space Agency.
“With testing of the sampling vehicle’s propulsion system next month, the dream of examining samples for the Red Planet will soon become a reality.”
