Perseverance’s hunt for life on Mars is officially on.
NASA’s newest Mars rover is getting ready to collect its first rock sample from the surface of Mars and stow it away for a future return mission to Earth, where NASA will test it for signs of ancient microbial life.
Perseverance’s science campaign has just begun, and the rover has already stumbled upon interesting rocks and sedimentary layers that tell a part of Mars’ larger history.
The Perseverance rover landed on Mars on February 18 and has been on a Martian road trip ever since to scour its landing site, Jezero Crater. Jezero is a 28-mile wide, 1,600-foot deep crater located in a basin slightly north of the Martian equator. It once housed an ancient lake estimated to have dried out 3.5 to 3.8 billion years ago.
Since landing on Mars, Perseverance has discovered two interesting pieces of information on Jezero:
- It may have had multiple cycles of drying up completely before filling back up with water again
- There are rocks at Jezero that may either be sedimentary or volcanic — two scenarios with wildly different and important implications
Ken Farley, a project scientist for the Perseverance mission, explains that the team behind the mission is currently trying to test the hypothesis of whether Jezero lake filled up with water just once or if it went through multiple episodes of filling up and drying down.
“This is very important because it means that we will have multiple time periods in which we could potentially learn about environmental conditions,” Farley says during a press conference on Wednesday. “And we also have multiple time periods where we might be able to look for evidence of ancient life that might have existed on the planet.”
Roving along — In the past several months, Perseverance has driven one kilometer to the south while investigating rocks on the crater floor, which represent an ancient part of Mars’ past that goes back billions of years ago.
One of the images captured by Perseverance showed a small cliff several meters across of a very finely layered rock, which the scientists believe may be fine-grain rock deposited at the bottom of the lake with mud that might have also been deposited and later turned into rock.
“This is exactly the kind of rock that we are most interested in investigating for looking for potential biosignatures in this ancient rock record,” Farley says.
Perseverance then stumbled upon rocks known as the paver stones, which are whitish in color. And those rocks also pose an interesting question for the mission scientists in helping them understand the history of Mars and its past habitability.
“We've been studying these in detail for some time trying to answer this most simple question — are these rocks volcanic, or are they sedimentary?” Farley says. “We've been talking about that for a while, and I'll tell you, we still don't have the answer.”
Why it matters — So, what is the significance of whether these rocks formed from sediment or formed volcanically?
Understanding the nature of the lake’s floor is crucial to reconstructing the history of water on Mars and knowing when the planet may have housed life.
If the crater has volcanic rock, then it is likely from a volcanic event that scientists have not yet identified on Mars.
“That's really important for our understanding and especially for sample return,” Farley says. “One of the special things about volcanic rocks is they can be dated back on Earth with very high precision and accuracy.”
Once the samples are returned to Earth, the scientists would be able to date the rocks and pin down the timing of Mars’ history.
About the Perseverance mission
The Perseverance rover will spend 687 days on Mars, the equivalent of one Martian year.
During this, the rover will collect samples of rock and dust from the Martian surface using its nine drill bits. But unlike previous missions to Mars, Perseverance will stow away those samples for a future sample return mission that will allow scientists to examine them in a lab on Earth.
Perseverance will leave the samples on Mars to be picked up by another mission in the next few years and be returned to Earth by the 2030s.