Yutu-2 took the risk of exploring a two-meter crater on the Moon and detected an unexpected gel-like material at its base.
China ‘s Yutu – 2 rover has found sticky terrain in the uncharted landscape of the far side of the Moon , its two-year travelogue reveals.
A study published in Science Robotics describes earthy soil, gelatinous rocks, and small new craters within the Von Karman Crater in the South Pole-Aitken Basin.
Researchers from the Harbin Institute of Technology and the Beijing Aerospace Control Center have analyzed the data and images collected by Yutu-2 , offering detailed geological knowledge at the landing site that can help deepen understanding of the formation and evolution of the Moon , reports Xinhua.
The Chang’e-4 probe and rover landed in Von Karman Crater on January 3, 2019. The rover has already been in service for three years, outliving its initial designed lifespan of three months.
bumpy road
During its journey , Yutu-2 slipped and skidded, indicating that the terrain on which it landed is dotted with gentle local slopes , albeit relatively flat on a large scale.
The rover, a six-wheeled all-terrain robot equipped with four steering motors in the corner wheels with a mesh surface, is capable of climbing 20-degree slopes and overcoming obstacles up to 20 centimeters high.
The study revealed that during the rover’s journey to a shared study site with the Chang’e-4 probe, its lug-reinforced wheels sometimes sank slightly into the ground and experienced moderate leaks in the wire mesh screen.
The researchers used the rover’s wheel as a trenching device to estimate lunar soil properties.
They found that the supporting property of the regolith is similar to that of dry sand and sandy loam on Earth, stronger than typical lunar soil from the Apollo missions.
They estimated, based on the muddy soil observed at Yutu-2’s wheels, that the soil there is stickier than the landing site of its predecessor Chang’e-3, which landed softly in Rainbow Bay on the near side of the Moon in December 2013, according to the study.
The researchers attributed the increased soil cohesion to the higher percentage of agglutinates in the regolith, which makes soil particles more likely to hold together when ground by wheels.
Since the blocky soil has adhered to the rover’s wheel lugs rather than its mesh surface, they suggested that the lug surface could be coated with a special non-stick material on future missions to improve the rover’s traction ability. machine.
fresh craters
On its eighth lunar day, Yutu-2 ventured to explore a two-meter crater and detected an unexpected gel-like material at the base of the crater.
The shimmering, dark greenish material is likely to be impact-melted rock, or impact-generated glass-coated breccia, a type of rock composed of sharp fragments embedded in a fine-grained matrix, according to the study.
Then Yutu-2 stopped, instead of driving down along the steep wall of the crater, fearing that lower the drawbar of the wheels were not strong enough to push back the rover, the researchers said.
Despite this, in its first 25 lunar days, the rover’s cameras captured images of a wide variety of craters, according to the study.
These include highly degraded craters with gentle slopes and flat rims, and craters with grain-sized ejecta, ranging from particles to lumps.
The ejecta craters were observed to have thick walls and bottoms, with debris evenly or unevenly distributed, the findings revealed.
The researchers said that these ejecta craters are not primary but secondary ones that were formed by a larger crater located to the west of the landing site, as they all faced northwest in line with the horizontal component of the impact force. ( EuropaPress )
