Chinese team develops Mars soil simulant to boost future exploration endeavors

BEIJING -- A team of Chinese geologists has created a Mars soil simulant that almost replicates Utopia Planitia soil, a scientific breakthrough that could be crucial for future explorations of the planet, including China's ambitious Mars sample-return mission.

The simulant, coded UPRS-1, comes very close to replicating the physical, chemical, spectral and mechanical properties of Martian soil based on in-situ data obtained by China's Mars rover Zhurong of the Tianwen 1 Mission and NASA's Viking-2 lander, both of which landed in the Utopia Planitia region.

Published in the planetary science journal Icarus, this breakthrough fills a gap in space exploration research by providing a soil simulant for Mars' northern lowlands -- an area previously overlooked in developing simulants, which focused on the southern highlands.

Utopia Planitia, a massive impact basin with a diameter of approximately 3,300 km, where China's Zhurong rover touched down in 2021, is a geologically significant region on Mars that may hold evidence of the planet's watery past.

An interdisciplinary research team from the Institute of Geology and Geophysics (IGG) under the Chinese Academy of Sciences, including Li Shouding, Li Juan and Lin Honglei, analyzed data from Zhurong's suite of instruments, which detected hydrated minerals like gypsum and clays, that are telltale signs of past liquid water activity and which make this region of Mars particularly valuable for study.

To recreate the unique soil composition in this region, the team employed an innovative approach -- combining geological expertise with planetary science.

They started with crushed basalt from East China's Shandong province as the base material, and then precisely blended in a specific formula of minerals, according to the study.

After this step, the mixture underwent analysis and adjustments to replicate the spectral, physical, mechanical and chemical properties of soil found at Utopia Planitia on Mars. The simulant shows an overall similarity of 86.1 percent in numerous properties compared with the actual regolith at Utopia Planitia.

The team subjected UPRS-1 to precise testing to ensure its mechanical properties replicate the critical parameters of soil on Mars, which will help engineers design more robust landers and rovers for future missions.

UPRS-1 is designed to address a long-standing challenge in space exploration that came into focus following the soil-drilling difficulties encountered by NASA's InSight mission in 2020.

The simulant opens new avenues for research into in-situ resource utilization, allowing scientists to develop and test technologies for extracting water from Martian soil -- a capability necessary for sustaining future human outposts on Mars.

UPRS-1, notably, can offer a vital testing ground for mission components and sampling techniques as China prepares for its Tianwen 3 sample-return mission, set to launch around 2028, the paper's first author Diao Yiming from the IGG, told Xinhua.

In terms of science, it can serve as material for use in Martian environment simulation experiments, with applications in astrobiology, such as investigating the effects of clay minerals and sulfates on microbial survival, the research team explained.

Also, the team proposed an evaluation procedure that could facilitate the design and creation of new high-similarity simulants applicable to other regions on Mars.