No sign of the planned lake bed where the Perseverance rover landed

Image of the rover's mast in the red environment of Mars.
Enlarge / No, those donut marks aren’t mine, officer.

The Perseverance rover landed in Mars’ Jezero Crater largely because of widespread evidence that the crater once hosted a lake, meaning the presence of liquid water that may have once harbored Martian life. And the landing was a success, placing the rover at the edge of a structure that seemed to be a river delta where the nearby highlands drained into the crater.

But a summary of the rover’s first year of data, published in three different papers published today, suggests Perseverance has yet to find evidence of an aquatic paradise. Instead, everything indicates that water exposure in the areas explored was limited and the waters were likely near freezing. While that doesn’t rule out finding lake deposits later, the environment might not have been as hospitable for life as “a lake in a crater” might have suggested.

put it all together

Perseverance can be seen as a platform for a wide range of instruments that provide a picture of what the rover is looking at. Even its “eyes”, a pair of cameras on its mast, can create stereo images with 3D information and offer information about the wavelengths present in the images. It also has instruments that can be held at rock level to determine their content and structure; sample handling equipment can perform chemical analysis of materials taken from rocks.

Although the new information is divided into separate documents according to the instruments from which the data comes, the main thing is that the three paint a coherent picture and complement each other.

For example, spectroscopy tools provide details about the chemical makeup of a sample, but they don’t tell us how those chemicals are distributed in a rock. In contrast, there are x-ray analysis tools that offer inaccurate chemical information, but they tell us how the chemicals they detect are located in relation to visible features in the rock. And the cameras on the rover’s mast can help us identify how widely similar rocks are distributed.

Collectively, these tools tell us that Perseverance has so far sampled rocks from two different deposits. The first includes the bottom of the crater where he landed, which is rich in iron and magnesium minerals. Above is a distinct formation which appears to be volcanic rock, although we cannot rule out that it was formed by liquefied rock from an impact.

Both deposits were clearly shaped by processes that we know occur on Mars. Many rocks have been shaped by the wind and may have undergone chemical weathering due to the atmosphere or exposure to radiation. In places shaded by the wind, loose regoliths accumulated, many of them with the characteristic red tint of Mars. There is also a variety of impact debris, including smaller ones in Jezero Crater.

But the big question is whether the materials show any indications that water was present. The answer is a little “yes, but…”

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