There is no sign of the expected lake bottom where the Perseverance rover landed

An image of the rover's mast in the red environment of Mars.
Zoom in / No, these brownie tracks aren’t for me, officer.


The Perseverance rover has landed in Mars’ Jezero Crater largely because there is ample evidence that the crater once hosted a lake, meaning liquid water that may once have hosted Martian life. The landing was a success, putting the rover on the edge of a structure that looked like a river delta as nearby highlands emptied into the crater.

But a first-year summary of the rover data, published in three different papers released today, suggests that Perseverance has yet to stumble upon any evidence of a watery paradise. Instead, all indications are that exposure to water in the areas explored was limited, and the water was likely close to freezing. While this does not rule out that he would find lake sediments at a later time, the environment may not be as inviting to life as a “crater lake” might suggest.

Put it all together

Perseverance can be seen as a platform for a wide range of tools that provide a picture of what the rover is looking at. Even his “eyes”, which are a pair of cameras on his mast, can create stereoscopic images with 3D information, providing information about the wavelengths present in the images. They also have tools that can be carried on the rocks to determine their content and structure; Sample processing devices can perform a chemical analysis of the material taken from the rock.

While the new information is broken down into separate sheets based on the tools the data came from, the main thing is that all three paint a consistent picture and build on each other.

For example, spectroscopy tools provide details of the chemical composition of a sample but do not tell us how these chemicals are distributed in the rock. In contrast, there are X-ray analyzers that give imprecise chemical information, but tell us about how the chemicals they detect are located compared to the visible features of the rock. Cameras on the rover mast can help us determine how common the similar rocks are.

Collectively, these tools tell us that Perseverance has sampled rocks from different deposits so far. The first includes the crater where it landed, which is rich in iron and magnesium based minerals. Above this is a separate formation that appears to be igneous rocks, although we cannot rule out that it was formed from liquid rocks after their collision.

Both deposits were clearly formed by processes we know to occur on Mars. Many of the rocks were shaped by the wind and may have undergone some chemical changes due to the atmosphere or exposure to radiation. In places shaded by the winds, loose regolith has accumulated, much of it the characteristic red color of Mars. There is also a variety of debris from the impacts, including some smaller debris within Jezero Crater.

But the big question is whether the materials show signs of water. The answer is a little “Yes, but…”

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