Earlier this month, the Perseverance rover set off to collect some rock samples on Mars. It was to be a key moment in the rover’s historic sample return mission, as Perseverance was supposed to collect, store, and return samples of Martian rock and soil to Earth. (The rocket that will capture the samples has not yet been launched, and may not be launched in nearly a decade; currently, Perseverance is doing the hard work of collecting samples.) So far, perseverance has been very successful: his perilous landing has succeeded perfectly, and ingenuity, the 4-pound helicopter that boarded a flight to Mars determinationOnce again, I overcame huge hurdles to It became the first powered flight on another planet. Compared to those feats, the next task of perseverance – digging a finger-sized hole in a rock – seemed simple. But after drilling, the collector tube came back empty. Mission control was in disbelief.
As a salon before mentionedScientists rushed to find out the reason for the disappearance of the sample. Did he miss the workouts somehow? It doesn’t look like that – images from the Red Planet have revealed a hole in the rock.
So what happened once the drill came out of the rock?
After some sleuthing, NASA’s Perseverance Team determined that the rocks likely crumble into “small fragments” — essentially, powder. While the rock sample crush was a disappointment to the team, it was also a lesson in Martian geology.
“It’s certainly not the first time that Mars has surprised us,” said Kiersten Siebach, associate professor of planetary biology at Rice University and co-scientist on the Science and Operations team for Perseverance. “A big part of the exploration is figuring out what tools to use and how to get close to rocks on Mars.”
Sebat explained that something similar sometimes happens to geologists here on Earth. Some rocks look solid, and their chemistry has retained their appearance. But weathering and erosion events can weaken that chemistry.
“If you take a walk in California, sometimes it looks like you’re walking next to a rock. But if you kick it, it turns to dust,” Sebach said. “Maybe it was something like this, where the weather was more than expected.”
Mars is a strange place geologically. The surface of the planet is rocky and dusty. Thanks to previous missions such as the Sojourner, Spirit, Opportunity and Curiosity rover, we know the soil is toxic. High concentrations of perchlorate compounds, that is, containing chlorine, have been detected and confirmed on multiple occasions. In some areas, there are volcanic basaltic rocks such as the type found on Earth in Iceland, Hawaii, or Idaho.
Raymond Arvidson, a professor of Earth and planetary sciences at Washington University in St. Louis and a member of the Curiosity science team, explained that there is a huge difference between Earth and Mars even though Earth has active tectonic plates – meaning that the Earth’s surface is made up of a wide area, the “plates” that Stretching across the continent which move and move and abut each other, creating valleys and mountains. This geology has given the land places like the Sierra Nevada mountain range. Mars, however, has never had plate tectonics.
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“Those very primitive rocks that are called basaltic, like we have in the oceans — that’s the dominant mineralogy and rock formation on Mars,” Arvidson said. “It’s basically a basalt planet – it’s not as complicated as it is here, and there aren’t a lot of rocks.” Crater Lake, a 28-mile-wide crater and former lake north of the Martian equator, where perseverance touched the city. Arvidson noted that the crater has a diverse geology: “It contains clays, which have faults and carbonates, much of which yields [around] Three and a half billion years ago.”
For this reason, scientists believe Jezero may be an ideal place to look for ancient signs of microbial life on Mars. Perseverance is now heading to its next sampling site in South Sete, which is within Jezero Crater.
Notably, the tubes and tools on the persistence were built to collect more solid specimens, because the goal of this mission is to see if these rocks contain evidence of microbes, or any ancient fossilized life.
Do these rocks contain evidence of life? Arvidson asked. “To answer these questions, you need to return the rock to Earth.”
These soft sedimentary rocks that turn to powder when digged are found “everywhere” on Mars, Arvidson said. Previous roving vehicles have encountered them, too.
“For example with Curiosity, which landed at Gale Crater in 2012—and we were driving up the side of a mountain called Mount Sharp—we encountered soft sedimentary rock that was easy to excavate, and we were returning powders,” Arvidson said. “Then we found really hard rocks that we couldn’t dig into, so we gave up. Jezero would have hard rocks and soft rocks.”
As Siebach previously mentioned, what happened with perseverance is a learning experience. Sebat said scientists are relying on a basaltic signal from orbit to determine the minerals and composition of the Jezero Crater floor.
“It’s a bit mysterious… We don’t see a strong sign of hydration or something in these rocks in particular, instead, they look like most rocks on Mars which means they have a lot of these volcanic minerals and some dust on them on top,” Note Seebach. However, orbital observation is not foolproof. “We don’t know if this crater is really volcanic,” Seebach added.
Hence, scientists will not always be sure of the consistency of the sample areas they choose to drill. But once they get to Mars, it’s a mixture of science, educated guesswork, and luck to really find what they’re looking for to bring them home.
“Some of these rocks may have a composition that makes them appear igneous, while they can be sedimentary or igneous rocks,” Sebach said. “These are the kinds of compositions we see that make it challenging and interesting.”
Sebat confirmed that she is confident that persistence will succeed in sampling some of the other rocks.
“It’s those surprises and those unexpected events that make us curious and ask more questions, and learn more about this history of Mars written in these rocks,” Sebach said. “If the sampling process doesn’t go as well as we expect, these surprises are ingrained in the discovery, and will prompt us to learn more.”
But the really exciting science will happen when the samples finally return to Earth.
“We’ll be able to learn a lot about Mars from those samples,” Sebach said.