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Almost a year after NASA’s Perseverance rover was launched on its nearly seven-month journey to Mars, the robotic explorer is preparing to collect its first Martian sample within the next two weeks.
This sample, which will be returned to Earth by missions in the 2030s, might contain evidence of whether there was past life on Mars.
The rover has also collected some of its first scientific observations of the red planet as it searches among the rocks and dust.
Perseverance landed in Jezero Crater in February. Billions of years ago, the site was home to an ancient lake and river delta. Since June 1, the rover has been explore a 1.5-square-mile area of the crater, known as the “Cratered Floor Fractured Rough,” in search of the crater’s deepest and most ancient layers of rock.
On the rover’s 7-foot (2-meter) long robotic arm is a drill that will help it collect samples to place inside its caching system within the belly of the rover. The process to collect Perseverance’s first Martian sample will take about 11 days – a lot longer than the 3 minutes and 35 seconds it took astronaut Neil Armstrong to collect the first lunar sample.
“When Neil Armstrong took the first sample from the Sea of Tranquility 52 years ago, he began a process that would rewrite what humanity knew about the moon,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate, in a statement.
“I have every expectation that Perseverance’s first sample from Jezero Crater, and those that come after, will do the same for Mars. We are on the threshold of a new era of planetary science and discovery.”
Perseverance will receive instructions from its teams on Earth ahead of collecting the first sample.
First, Perseverance will align itself so that everything needed for sampling can be reached by the robotic arm, followed by an image survey using the rover’s suite of cameras. This survey will allow the rover’s science team to select the site of the first sample, as well as a separate target in the same area.
They will analyze the second target first before collecting the sample at the first target.
“The idea is to get valuable data on the rock we are about to sample by finding its geologic twin (nearby) and performing detailed in-situ analysis,” said Vivian Sun, science campaign co-lead at NASA’s Jet Propulsion Laboratory in Pasadena, California.
The rover will use an abrading tool to scrape off the top layers of the rock, blow it clean and study it using Perseverance’s science instruments.
Together, these instruments will provide an in-depth look, including a mineral and chemical analysis, of the Martian rocks.
On sampling day, the rover’s arm will retrieve a sample tube from its cache inside Perseverance’s belly and drill about 5 centimeters into the untouched twin of the rock it analyzed. This sample will be about the size of a piece of chalk.
Then, the sample’s volume will be measured, photographed, sealed and stored within the rover.
Each sample will tell a different piece of the Martian story.
Dozens of samples to be collected eventually
As Perseverance continues to investigate this part of the crater, it will continue to drive and collect four unique samples. These will later be cached on the surface of Mars for a future mission to pick them up and return them to Earth. The rover will collect around 40 samples during its two-year mission.
“Not every sample Perseverance is collecting will be done in the quest for ancient life, and we don’t expect this first sample to provide definitive proof one way or the other,” said Ken Farley, Perseverance project scientist at the California Institute of Technology, in a statement.
“While the rocks located in this geologic unit are not great time capsules for organics, we believe they have been around since the formation of Jezero Crater and incredibly valuable to fill gaps in our geologic understanding of this region – things we’ll desperately need to know if we find life once existed on Mars.”
Conducting science on Mars
The main goal of the Perseverance rover is to help unlock the history of Mars, taking us back to a time when the planet was warmer and wetter, in a quest to understand whether life ever existed on the red planet.
“We’re getting amazing data back. The site we’re in is absolutely spectacular, and we’re getting beautiful, national park-like views every day looking off across Mars,” said Briony Horgan, part of the rover’s science team and associate professor of planetary science in Purdue University’s Department of Earth, Atmospheric, and Planetary Sciences in the College of Science, in a statement.
Perseverance has been on a bit of a summer road trip, traveling about 328 feet (100 meters) a day thanks to its autonomous navigation capability.
Perseverance’s instruments can zap rocks with lasers to help scientists understand if the rocks on Mars are sedimentary or igneous, which would reveal more about water flow and ancient Martian environments. If the rocks are igneous, they were formed by volcanoes. But sedimentary rocks would contain layers of information from the lake itself.
The rover is currently driving over what the scientists call paver stones, and they are eager to learn if they are sedimentary or volcanic.
One hypothesis the scientists are trying to test is whether the lake within Jezero Crater had multiple episodes of filling up and drying down.
“This is very important because it means that you will have multiple time periods in which we could potentially learn about environmental conditions on Mars,” Farley said. “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.”
Images taken by Perseverance of the ancient river delta have revealed something surprising.
There are signs that flash flooding occurred within the delta, likely capable of moving large boulders, late within the lake’s history. None of this was visible in images obtained from orbiters around Mars. It took Perseverance investigating on the ground to find out.
Perseverance has spied a wealth of rocks that intrigue scientists. One of those is a small hill of layered rocks called Artuby, nicknamed for a river in southern France.
The rocks appear to have formed within the lake itself, likely lake mud that turned into rock over time. And those rocks could contain evidence of ancient life or even microfossils.
“This is exactly the kind of rock that we are most interested in investigating while looking for potential biosignatures in this ancient rock record,” Farley said.