The Perseverance rover has captured its first two slices of Mars.
NASA’s latest rover, it arrived on the Red Planet in February. On September 1, it drilled into a flat rock nicknamed Rochette. That allowed the rover to fill a roughly finger-sized tube with stone. This sample is the first ever intended to be brought to Earth for study. On September 8, the rover snagged a second sample from the same rock. Both are now stored in airtight tubes inside the rover.
The rover is supposed to get two samples from every rock it drills. This is “a little bit of an insurance policy,” explains Katie Stack Morgan. It means the rover can drop identical sets of samples in two different places on Mars. That boosts the chances that a future mission will be able to retrieve at least one set. Stack Morgan is the deputy project scientist for the Perseverance mission. She works at NASA’s Jet Propulsion Lab in Pasadena, Calif.
The successful drilling is a comeback story for Perseverance. The rover’s first attempt to take a bit of Mars failed. The sample crumbled to dust, leaving an empty tube. Scientists think that rock was too soft to withstand the drill.
Nevertheless, the rover persevered.
Rochette is a hard rock. It appears to be less severely eroded by millennia of Martian weather than are other rocks. Rover measurements of its texture and chemistry suggest the rock is made of basalt. This is a type that forms when lava cools. So Rochette may have once been part of an ancient lava flow.
Sampling volcanic rock is useful because these rocks preserve their ages well, Stack Morgan says. Measuring the concentrations of the isotopes of certain elements reveals exactly how old a piece of basalt is. Scientists have to do those measurements with equipment here on Earth, though. So this type of study has never been done on a pristine Martian rock.
Rochette is also interesting because it contains salt minerals. These salts probably formed when the rock interacted with water over long periods. That hints that groundwater once moved below Mars’ surface. Perhaps that groundwater means the region the rock came from was once habitable.
“It really feels like this rich treasure trove of information for when we get this sample back,” Stack Morgan says.
Scientists on Earth could someday search for tiny fluid bubbles trapped inside Rochette’s salts. The fluid would be left over from when Jezero crater — where Perseverance is exploring — was an ancient lake. Back then, the area may have been able to support life, said Yulia Goreva at a news briefing on September 10. Goreva is a planetary scientist. She also works at NASA’s Jet Propulsion Lab.
Scientists will have to be patient to analyze the newly collected rocks. The earliest any samples could make it to Earth is 2031. But it’s still a historic milestone, says Meenakshi Wadhwa. She’s a planetary scientist at Arizona State University. That’s in Tempe. “These represent the beginning of Mars sample return,” Wadhwa said at the news briefing. “I’ve dreamed of having samples back from Mars to analyze in my lab since I was a graduate student. We’ve talked about Mars sample return for decades. Now it’s starting to actually feel real.”