The latest scans of the Martian Jezero crater by NASA’s Perseverance rover have confirmed what scientists previously suspected—that there was once an ancient lake there. The findings offer renewed hope that we might find traces of life in the crater, which could be revealed in rock samples.
In a study published Friday in Science Advances, scientists used ground-penetrating radar —which allows them to peer through layers of rock 20 meters below the surface of the crater’s western delta—to paint a picture of the crater’s geological history.
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At some point in the past, parts of the crater wore away before it filled with water, forming a lake. That water later subsided again before flooding back in, each time either carrying sediment in or taking it out of the crater. This pattern of deposition and erosion showed up as regular, horizontal bands on the radar’s images.
The patterns match up with earlier images taken by cameras on the Mars Reconnaissance Orbiter. Previous studies that analyzed those images taken from space had concluded that the sediment layers came from erupting Martian volcanoes rather than water flow.
“This fits our expectations or hopes about what these layers might be like. The fact that we see this in the radar images is exciting,” David Paige, lead author on the latest study and who’s team had previously theorized the layers came from a lake, told Motherboard.
Figuring out how the sediment got to the crater is important, said Paige, because it will help scientists more accurately analyze the rock and dust samples that the Perseverance Rover is currently collecting. “The rover observations are more reconnaissance. They’re not going to provide any definitive answers on their own,” he said.
So far, Perseverance has collected 23 out of a planned 38 samples from the Jezero crater, which will be brought back to Earth in a joint effort by NASA and the ESA. The ultimate goal is to look for ancient signs of microbial life in the rocks as well as other geological evidence about how the planet evolved.
“We don’t know if there’s life on Mars but the fact that we can see these lake bed sediments means that it might be a reasonable place to look for it. The fact that we’re seeing these layers keeps hope alive that there might be something,” said Paige.
He added that it’s possible to store the samples for many years, meaning future scientists, armed with yet-undiscovered technology, could analyze the rocks and dust in ways we can’t even imagine yet.
This study is the first in what Paige says will be an ongoing string of discoveries coming out of Perseverance, which has so far spent more than a thousand sols (Martian days) on the Red Planet. “We’re just the first to get our results published so we’ll hear a lot more about the unfolding story here.”
Perseverance’s robotic teammate, the Ingenuity Mars Helicopter, ended its journey on Thursday after three years when one of its rotor blades sustained damage on landing. Scientists are now downloading the final images and data from the copter.
