Recent water detected in sand dunes by China’s Mars rover

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

This discovery highlights new potentially fertile regions in the warmer regions of Mars where conditions may be suitable for the existence of life, although further study is needed.

Friday’s news comes days after mission leaders acknowledged that the Zhurong rover had yet to wake up since it hibernated on Mars nearly a year ago.

The solar panels are likely covered in dust, choking off the power supply and possibly preventing the rover from working again, said Zhang Rongqiao, chief designer of the mission.

Before Zhurong Silence, I noticed rich salt dunes with cracks and crusts, which the researchers said likely mixed with melting frost or morning snow a few hundred thousand years ago.

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

Conditions during that period were similar to those on Mars now, with rivers and lakes dried up and no longer flowing as they did billions of years ago.

The Beijing-based team wrote in a study published in the journal Science advances.

“We think it could be a small amount, nothing more than a film of water on the surface,” co-author Xiaoguang Qin of the Institute of Geology and Geophysics said in an email.

The rover did not directly detect any water in the form of sleet or ice. But Chen said computer simulations and observations by other Mars spacecraft have indicated that even today at certain times of the year conditions may be right for water to appear.

What sets the study apart is how young the dunes are, said planetary scientist Frederic Schmidt of the University of Paris-Saclay, who was not part of the study.

“This is clearly a new scientific part of this region,” he said in an email.

The Chinese scientists said that small pockets of water from melting snow or ice mixed with salt likely resulted in small cracks, hard scaly surfaces, loose particles and other characteristics of the dunes such as depressions and ridges. And they ruled out that winds were a cause, as well as frost made of carbon dioxide, which makes up the bulk of the Martian atmosphere.

Mars frosts have been observed since NASA’s Viking missions in the 1970s, but this light dusting of morning frosts is thought to occur at specific locations under specific conditions.

The rover has now provided “evidence that there may be a broader distribution of this process on Mars than previously identified,” said Marie Burke of Trinity College Dublin, an expert in the geology of Mars.

She added that although this aquatic place is small, it could be important for determining habitable environments.

The six-wheeled Zhurong — named after the god of fire in Chinese mythology — was launched in 2020, arrived at Mars in 2021 and spent a year wandering before entering hibernation last May. The rover ran longer than required, going over a mile (1,921 metres).

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