Jezero Crater sits within the Isidis Planitia region of Mars, where an ancient meteorite impact left behind a large crater some 750 miles (1,200 kilometers) across. This event is known as Isidis impact, and it forever changed the rock at the base of the crater. A later, smaller meteorite impact created the Jezero Crater within the Isidis impact basin. Scientists believe that these events likely created environments friendly to life. There is evidence of ancient river flow into Jezero, forming a delta that has long since been dry.
Jezero Crater is thus likely to have been habitable in the distant past. The Mars Reconnaissance Orbiter's CRISM instrument has revealed that the crater contains clays, which only form in the presence of water. On Earth, scientists have found such clays in the Mississippi river delta, where microbial life has been found embedded in the rock itself. This makes Jezero Crater a great place to fulfill the Mars 2020 mission's science goal of studying a potentially habitable environment that may still preserve signs of past life.
At Jezero Crater, Perseverance should be able to access rocks that are as old as 3.6 billion years. There are many ideas about what early Mars was like, and how it came to be what it is today. Accessing the ancient rock at Jezero should help answer some of these questions, and tell us more about the formation of rocky planets. It is also a great location for the rover to collect a variety of samples of Martian rock and soil.
The Name Game at Jezero CraterNaming things is a great way to remember them. As Perseverance explores the Martian surface, the science team will assign unofficial names to especially interesting regions, features, and samples. This naming system is similar to the one used to name the Mars locations that the Curiosity rover has explored on Mars.
For Perseverance, the team has divided up the entire landing site, Jezero Crater, into squares. Each square will be matched to national parks and preserves on Earth with similar geology. As a nod to the diversity of the international science team, the plan is to find matching sites in countries that have contributed to the mission. As the rover explores Jezero Crater, any time the team sees an interesting feature, they will name it for a corresponding location here on Earth.
Within an area or region, individual features and rock targets will be named for locations within the Earthbound region for which it is named. For example, when the Curiosity team named one of its sites “Yellowknife Bay” after a location in Canada, individual rocks and targets within that area were named after features in Canada’s Yellowknife Bay.