Since landing on Mars in February 2021, NASA's Perseverance rover has continued to push the boundaries of planetary exploration. Its goal: to investigate the Jezero crater to better understand the geological history of the red planet and discover if it could have supported life. After several months of exploration, Perseverance recently reached another important milestone by arriving at the top of the crater, which marked the start of a new phase of its mission.
The choice of Jezero crater: an ideal research site
Jezero Crater was selected by NASA for its geological richness and potential to reveal crucial information about the ancient history of Mars. This site, once a lake, is home to a delta, a geological structure formed by deposition of sediments transported by an ancient watercourse. On Earth, deltas are environments that support life due to the presence of water, an essential element for biology. Additionally, these areas are often rich in organic matter and minerals that can trap traces of past life.
The Jezero Crater region is particularly interesting, as it is composed of claysminerals capable of preserving biosignatures (clues of microbial life dating back billions of years). Clays can act as time capsules by locking organic molecules within their structure, making them prime targets for scientists searching for traces of past life on Mars.
The crater is a prime site for studying conditions on Mars when the planet was warmer, humid and potentially habitable. Analysis of sediments deposited by ancient waters could offer clues about the climatic evolution of Mars and the development of life in the distant past.
The journey of Perseverance: exciting scientific campaigns
Since its arrival on Mars, Perseverance has already carried out several scientific campaigns. After placing its rover on the crater floor, the science team chose different sites to collect samples. The rover explored the “crater floor”, the “upper cone” and the “deltaic cone” by collecting rock and soil samples that can provide information about the geological history of the region.
Each campaign allowed the rover to map a portion of the crater and collect information crucial to understanding the geological processes that shaped Mars. One of the important discoveries was the analysis of the clays of the deltaic fan which contain possible traces of ancient water present in the region.
More recently,fter exploring the lower areas of the crater, Perseverance finally reached the summit, a milestone in its journey. This site, called “Lookout Hill”, offers a unique panorama over the entire crater and marks the start of the “Northern Rim” campaign. In this new phase, Perseverance will head towards rocky outcrops located on the crater rim, an area where particularly old rocks are exposed. Formed ago approximately 3.9 billion yearsthey are among the oldest ever observed on Mars.
Tracing geological history and the quest for past life
The crater rim is of critical importance to scientists because it houses fragments of the early Martian crust. These ancient rocks, thrown to the surface during the impact that formed the crater approximately 3.9 billion yearsare precious witnesses of the first days of Mars. By studying them, researchers hope to discover key information on the formation of the red planet, but also on its similarities with Earth.
The analysis of rocks from the edge of the crater is also crucial for tracing the significant events of the Noachian perioda geological time when Mars was warmer and wetter, providing an environment conducive to surface water flow. This period is therefore a central axis of research, because it could provide clues about the habitability of the planet at that time.
Perseverance's research not only explored these ancient rocks, but also examined geological features that help us understand why Mars, now cold and barren, has changed over time. By tracing the planet's geological history, scientists hope to understand the reasons for this transition and how the planet evolved into the hostile environment we know today.
Thus, each sample collected by Perseverance, each rock layer explored, could potentially provide answers to the questions that have fueled researchers for decades.
