China’s Zhurong rover has provided one of the few peeks into what lies beneath the surface of Mars.
Data returned by Zhurong’s ground-penetrating radar instrument reveals evidence of craters buried just below the surface of the March and other, sloping features of less certain origin, according to a new paper.
This view of the Martian surface, which shows several clear features, stands in stark contrast to the shallow subsurface structure of Earth’s moon, also revealed by ground-penetrating radars. The Moon’s top 33 feet (10 meters) consists of fine layers that have been ground up by a bombardment of micrometeorite impacts.
Related: Will China’s Zhurong Mars rover wake up from its worrying hibernation?
The difference can be explained by Mars’ thin atmospherewhich provides protection against micrometeorites and also has weathering effects on the surface.
“We found many dunes on the surface at the landing site, so maybe this crater was quickly buried by the sand and then this cover reduced space weathering, so we can see the full shape of these crater walls,” Yi Xu, lead author of the study, said in a statement (opens in a new tab).
Zhurong was launched in July 2020 along with Tianwen 1 mission orbiter and landed on the great plain of Utopia Planitia in May 2021. The rover traveled 6,302 feet (1,921 meters) south from the landing site during the following Earth year.
The landing site was chosen for engineering and science criteria, with the area believed to host shorelines of a possible ancient seas. One goal of Zhurong’s ground-penetrating radar — which pings electromagnetic signals from subsurface rocks and collects their reflections — was to search for evidence of water or ice trapped below the surface.
It uses two different frequency ranges, with the frequency used for this study providing fine detail, but only to a depth of about 15 feet (4.5 m). No water was found in this study, but the second radar frequency reaches down to about 260 feet (80 m).
Scientists hope that opening this window into the subsurface of Mars will provide insight into Mars’ geological evolution, clues about past climate conditions and possibly evidence of the presence of water or ice. NASA’s Endurance also carries a ground-penetrating radar instrument, which provides new insight into its surroundings, the floor of Mars’ Jezero crater.
The research paper was published (opens in a new tab) on February 9 in the journal Geology of the Geological Society of America.
Meanwhile, the fate of the Zhurong rover itself is currently unknown. The solar-powered rover went into hibernation in May 2022 due to winter in Mars’ northern hemisphere. It was expected to resume activities autonomously in December, but Chinese space authorities has not commented at the apparent silence of the rover.
NASA’s Mars Reconnaissance Orbiter recently imaged Zhurong from orbit, showing that the rover has not moved since the hibernation period began. The rover can wake up when the heat and light conditions improve in Utopia Planitia.
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