What we learned from the Perseverance Rover’s first year on Mars – Deccan Herald

One year ago NASAs Perseverance rover plunged through the Martian atmosphere and safely landed in Jezero Crater, a 45-kilometre-wide gouge that scientists suspect once hosted a deep, long-lived lake. The rovers ultimate target is near Jezeros western edge: a large, fan-shaped pile of sediments that washed into the basin through a notch in the crater rim about 3.5 billion years ago. In other words, the target is a river deltathe exact type of environment that could preserve signs of ancient Martian life-forms.

Perseverance is the tip of the spear in humanitys grand quest to find traces of a relict Martian biosphere. The $2.7-billion missions overarching objective is to collect dozens of Martian rock samples, many of them from the delta. Then, sometime in the early 2030s, a sequence of spacecraft should return those samples to Earth for up-close scrutiny, possibly allowing scientists to at last answer the question of whether the solar system was ever home to more than one life-bearing world.

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Perhaps past microbial life could have existed on Mars when it was a little warmer and a little wetter, says Lori Glaze, director of NASAs planetary science division. The surface of Marsthe geology, the geologic historyis preserved. We can see back 4.3 billion years on the surface... You cant do that in other places.

Stitched together from 16 images captured by NASAs Perseverance rover, this video pans across a panoramic view of a portion of Jezero Crater, revealing brown hills in the middle distance that are part of the craters ancient river delta.

Perseverances early observations are already revealing that Jezeros geologic history is richer than previously imagined, with dramatic shifts in environmental conditions. Now, as the rover ramps up its sample-collection campaign, scientists back home are eager to send it west, toward the alluring river delta and its potential biological treasure. Mars, however, does not always play by the rules. Already the planet has thrown a few unanticipated challenges into the rovers first Earth year on the Martian surface.

Every time weve sent a mission to Mars, weve had to learn more about how Mars actually is going to treat our spacecraft, and we have to learn how to operate in that environment, Glaze says. But Perseverance is doing well, she adds. Things are moving along at a really good clip. [The team is] making pretty great progress.

Early Science outside the Landing Strip

Perseverance is not alone in celebrating its first Martian anniversary. It was one of three space missions to reach Mars last February. The United Arab Emirates Hope orbiter is still circling the planet. And Chinas multicomponent Tianwen-1 missioncomposed of an orbiter, a lander and a roveris there, too. That missions rover, Zhurong, is currently exploring a Martian plain called Utopia Planitia, some 1,800 kilometres northeast of Perseverances location.

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Back in Jezero Crater, however, Perseverances Martian adventures took an unexpected turn almost right away, starting with where the rover touched down on February 18, 2021.

In all of the simulations that were done beforehand, the most likely place to land was a big, flat area that we started calling the landing strip right in front of the deltaI mean, literally within 100 meters of the front of the delta, says the California Institute of Technologys Ken Farley, the missions project scientist. So we were joking around that on February 19 we were going to wake up looking at a wall in front of us. And, um, we didnt.

Annotated satellite image of Jezero Crater dated December 15, 2021, shows the route Perseverance (light blue dot) had taken (white line) into the craters Stah region since touching down on February 18, 2021. The rover would retrace its path back to the landing site before following a new route (blue line) to Jezeros river delta. Credit: NASA/JPL-Caltech

As the rover descended to the surface, an onboard navigation system autonomously guided Perseverance to an area the software had deemed safewhich it was. But instead of landing within an Earth days drive of the delta, the rover ended up about 2.5 kilometres away, on the other side of a treacherous, sandy, rock-strewn terrain called Stah, which is Navajo for amid the sand. Circumnavigating that patch would more than double the length of the rovers path to its primary exploration target. Yet as Perseverance scouted its immediate surroundings, mission controllers chose to let it linger on the crater floor and explore Stah before doubling back and heading to the delta.

I worked on Curiosity ever since it landed in Gale Crater, says Perseverances deputy project scientist Katie Stack Morgan of NASAs Jet Propulsion Laboratory (JPL). And [with] that very first image that we got down from Perseverance, I looked at that landscape and thought, Wow, we are not in Gale Crater anymore. This is nothing like [what] I have ever seen in Gale.

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Instead of landing in lake sediments, the rover found itself on fractured bedrock littered with bizarre, sometimes dusty rocks. Many of those rocks are covered in an intriguing purplish coating that resembles desert varnishes on Earthpatinas associated with hardy, radiation-resistant types of terrestrial microbes. Initially, rock textures and geochemistry defied classification. But once the rover had ground through the weathered surface of a Jezero rock, scientists, saw exactly what they would have expected in a lava flownot a lake bottom.

All of the rocks that we have confidently identified are igneous, Farley says. They have nothing to do with the lake.

Produced volcanically, the igneous rocks on Jezeros floor contain large olivine crystals that typically form near the bottoms of thick lava lakes and flows. Scientists still do not know how or when the rocks ended up in Jezero, but it is now clear that the surface Perseverance is rolling across is not the original crater floor. Further investigations revealed that the rocks have been altered by water, which excavated small tunnels and pockets in their interiors that are now filled with salty minerals. At least on Earth, such minerals are perfect for preserving signs of life. Their presence, plus the mysterious purple varnishes, make these volcanic rocks unexpectedly tantalising targets.

Igneous rocks are typically not where you look to find signs of life because they come from really hot magmas that life doesnt necessarily favour, Stack Morgan says. But when you have these rocks sitting on the surface or in the subsurface interacting with water, then youre creating small niches within the rock itself that could be habitable. Youve got chemical ingredients in there; youve got water in there; youve got precipitation of salt minerals.

As Perseverance cast its gaze farther afield, it spied Jezeros mountainous crater rim and the wall of the delta. (We confirmed we do a have a delta, so check that box, Stack Morgan says.) It also spotted a curious rocky outcrop called Kodiak, which team members have used to gauge the depth of Jezeros ancient waters. Patterns on the rock suggest that on at least one occasion, water levels dipped surprisingly low, falling to more than 100 meters below an outflow channel to the east. Other observations provide hints of a deluge that gushed into the crater with enough power to carry along the large boulders now haphazardly strewn in some areas. In other words, Jezeros lake was occasionally stable and placid and at other times flushed by periods of intense runoff.

Rock layers of Kodiak, a flat-topped hill near the centre of this image, reveal ancient chapters of Jezero Craters history marked by gradual sediment deposition followed by massive flooding.

And oddly, Jezero appears to be much windier than anticipated. Fortunately, that has not bothered Perseverances robot friend, the helicopter named Ingenuity. Since April 2021 Ingenuity has been performing wellso well, in fact, that after its initial tests, the team began using it to help guide the rover through tricky terrains such as Stah. It aced those tests, Farley says. Now it is our companion, and it is continuing to fly and do recon for us.

Go West, Young Rover

Collecting and storing samples has also turned out to be trickier than anticipated. Last August, when Perseverance took its first shot at collecting a rock core, mission personnel were optimistic. They had tested the machinery on terrestrial rocks and performed extensive troubleshooting on the software guiding the process. The target rock showed no obvious challenging quirks. The task should have been easy.

But the first coring tube was devastatingly empty. To come up with a zero-volume empty tube was just mind-blowing, unfortunately, says JPLs Jessica Samuels, sample caching system lead for the mission. That was never something we were worried aboutnot acquiring the sample. We were worried about so many other things.

The rock, it turned out, had been so altered by water that it crumbled under the pressure of Perseverances drillnot an ideal result but one that left the team with a useful tube full of Martian atmosphere. That first sample failure was stressful, however, and if the problems continued, they could have scuttled the once-in-a-lifetime chance to gather and return pristine material from Mars.

View of NASAs Martian helicopter Ingenuity in flight, as seen by the Perseverance rover on April 25, 2021.

Since then the team has regrouped and successfully collected six rock cores, which Samuels says is validation that the system actually works as planned. Its not us. Its Mars, she says. Indeed, Mars served up another episode of sample-collecting shenanigans when pebbles recently wedged themselves into the rovers sample-caching hardware and Perseverance had to do a bit of a shimmy to shake them loose.

Theres never a dull moment in sampling, Samuels says. Its keeping us on our toes. And its keeping us continuing to think about the different environmental conditions.

Overall retrieving a small cache of samples from Mars is an audacious task that is just barely within our technological grasp, even if each of the missions moving parts performs perfectly. Were pushing the limits of the technology we have today to land and launch a rocket from Mars that is essentially just big enough to get a basketball into orbit, says Albert Haldemann, chief Mars engineer at the European Space Agency, a partner in the overall sample-return effort.

Perseverances already-collected igneous rock cores can be used to measure the strength of Marss ancient magnetic field and to precisely pin ages on the craters epochs. For now, scientists guess that water sloshed around in Jezero around 3.5 billion years ago, but Farley says there are half a billion years of uncertainty in that estimate. Soon, team members say, they will begin deciding when and where Perseverance should deposit a preliminary cache of materialsjust in case the rover is no longer functioning by the time the next spacecraft arrives to retrieve its bounty.

If everything is onboard Perseverance, and Perseverance dies unexpectedly, weve got nothing, Haldemann says. So a safety cache will be put down at a potential landing spotsooner rather than later.

Before it leaves the crater floor, Perseverance will fill two more of its 43 onboard, ultraclean sample tubes. Then it will turn west and make haste: Were gonna gun it for the delta, Stack Morgan says.

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What we learned from the Perseverance Rover's first year on Mars - Deccan Herald