China’s Mars rover finds signs of recent water in sand dunes

Water may be more widespread and newer to Mars than previously thought, based on Chinese rover observations of Martian sand dunes.

The discovery highlights new, potentially fertile areas in warmer regions of Mars where conditions could be right for life, although further study is needed.

Friday’s news comes days after mission leaders acknowledged that the Zhurong rover has yet to wake up since entering hibernation for the Martian winter nearly a year ago.

Its solar panels are likely covered in dust, smothering its power source and possibly preventing the rover from functioning again, said Zhang Rongqiao, the mission’s chief designer.

Before Zhurong fell silent, he observed salt-rich dunes with cracks and crusts, which researchers say were likely mixed with melting morning frost or snow a few hundred thousand years ago. ‘years.

Their estimated date range for when fissures and other dune features formed in Mars’ Utopia Planitia, a vast northern hemisphere plain: sometime after 1.4 million to 400,000 years ago or even before.

Conditions during this time were similar to those on Mars today, with rivers and lakes drying up and no longer flowing as they did billions of years earlier.

Studying the structure and chemical composition of these dunes can provide insight into “the possibility of water activity” during this time, the Beijing-based team wrote in a study published in Scientists progress.

“We think it might be a small amount…no more than a film of water on the surface,” co-author Xiaoguang Qin from the Institute of Geology and Geophysics said in an email.

The rover did not directly detect water in the form of frost or ice. But Qin said computer simulations and observations of other spacecraft on Mars indicate that even today, at certain times of the year, conditions could be right for water to appear.

What’s remarkable about the study is how young the dunes are, said planetary scientist Frédéric Schmidt of the University of Paris-Saclay, who was not part of the study.

“This is clearly new science for this region,” he said in an email.

Small pockets of water from melting frost or snow, mixed with salt, likely resulted in small cracks, hard and crusty surfaces, loose particles, and other dune features such as depressions and ridges. ridges, the Chinese scientists said. They ruled out wind as the cause, as well as frost made up of carbon dioxide, which makes up most of Mars’ atmosphere.

Martian frost has been observed since NASA’s Viking missions in the 1970s, but this light dusting of morning frost was thought to occur in certain places under specific conditions.

The rover has now provided “evidence that there may be a wider distribution of this process on Mars than previously identified,” said Mars geology expert Mary Bourke of Trinity College Dublin.

As small as this aquatic niche is, it could be important for identifying habitable environments, she added.

Launched in 2020, the six-wheeled Zhurong – named after a god of fire in Chinese mythology – arrived on Mars in 2021 and spent a year wandering around before going into hibernation last May. The rover ran longer than expected, covering more than a mile (1,921 meters).

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