Perseverance and Ingenuity Probe Jezero Crater: An Ongoing Exploration at 1,000 Sols into the Mission

NASA’s Perseverance rover and Ingenuity helicopter have reached a major milestone in their mission on Mars, celebrating their 1,000th sol, or Martian day, on the Red Planet. The robotic pair has been exploring Jezero Crater and recently completed an extensive investigation of the ancient river delta within the crater. This river delta contains evidence of flowing water that may have once filled Jezero thousands of years ago.

As part of its investigation, Perseverance has been collecting samples of the Martian surface, rocks, and other interesting features. So far, the rover has collected 23 surface samples as part of the Mars Sample Return mission. Scientists have already made some significant discoveries from these samples. For instance, one of the recent samples, named “Lefroy Bay,” contained high amounts of fine-grained silica, which is known to preserve ancient fossils on Earth. Another sample, called “Otis Peak,” contained large quantities of phosphate, a compound often associated with life. Both samples also contained carbonate, which can preserve environmental conditions from when the samples were formed.

The choice to explore Jezero Crater was based on orbital images that revealed the presence of a delta, indicating that a large lake once filled the crater. This lake provided a potentially habitable environment and the delta rocks are ideal for preserving signs of ancient life as fossils. After thorough exploration, scientists have pieced together the crater’s geologic history, tracking its lake and river phases from beginning to end.

Before Perseverance landed on Mars in February 2021, scientists could only speculate about what Jezero Crater was like. However, the rover’s discoveries have provided new insights. It found that the crater floor is made of igneous rock, suggesting that it was formed from volcanic activity or magma under the surface. By studying sandstone and mudstone layers, scientists could determine when rivers began flowing, a few hundred million years after the asteroid impact that formed the crater. The presence of salt-rich mudstones indicated the existence of a shallow lake that experienced evaporation. As the lake filled up, fast-flowing waters carried boulders from outside Jezero into the lake, ultimately distributing them throughout the crater. Based on further discoveries, scientists estimate that Jezero’s lake was once as wide as 35 kilometers and as deep as 30 meters.

The ultimate goal of collecting these samples is to return them to Earth through the Mars Sample Return mission. This will allow scientists to study the Martian surface and its features in great detail, as Perseverance has limited instruments for sample analysis. But how do scientists choose where to collect samples? They first identify specific areas or surface features that hold valuable information about Mars’ environment and history. Perseverance then uses an abrasion tool to expose a small portion of the target, which is then analyzed using various instruments, including the Planetary Instrument for X-ray Lithochemistry (PIXL).

For example, during a recent sample collection at “Bills Bay,” PIXL detected carbonates within the abraded rock. Carbonates can form in watery environments and may preserve organic molecules, which can be formed through geological and biological processes. The presence of silica in Bills Bay also contributes to its potential for preserving organic molecules. Another sample target, “Ouzel Falls,” contained iron closely associated with phosphate. Phosphate is an essential component of DNA and cellular membranes in terrestrial life forms. While Perseverance has yet to detect any structures or chemical changes that could indicate ancient microbial life, the presence of carbonates and phosphates in these samples suggests a watery and habitable environment.

Now that the science campaign at Jezero’s river delta is complete, Perseverance and Ingenuity will move on to their fourth campaign, investigating the crater margin near the canyon entrance. Deposits rich in carbonate have already been spotted in this area. The exploration of Jezero Crater continues to provide valuable insights into Mars’ history and its potential for ancient life.