In July 2020, China launched Tianwen-1, its first interplanetary mission. By May 2021, the Zhurong rover safely touched down on the Martian surface in southern Utopia Planitia, a vast impact basin long suspected of holding evidence of ancient oceans.1
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For decades, planetary scientists have debated whether Mars once hosted large standing bodies of water. With Tianwen-1, China joined the small circle of nations capable of conducting orbiting, landing, and roving in one integrated mission.2
Recent analyses from orbital imagery and rover data have identified terrain features on Mars that resemble ancient shorelines, such as ridges, terraces, and layered sediments. If confirmed, these findings would lend strong support to the theory that a northern ocean existed on the planet around 3.5 billion years ago. They also offer valuable new insights into Mars’ past climate and its potential to have supported life.1-2
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What Is the Tianwen-1 Mission?
China’s first Mars exploration mission, Tianwen-1, consists of an orbiter, lander, and the Zhurong rover, which successfully touched down in southern Utopia Planitia in May 2021. The orbiter carries seven instruments, including high-resolution and moderate-resolution imaging cameras, a mineralogical spectrometer, a subsurface radar, a magnetometer, and particle analyzers. These were designed to map the Martian surface, study its ionosphere, and search for subsurface ice.3
The Zhurong rover is equipped with six payloads including navigation and terrain cameras, a multispectral camera, ground penetrating radar, a magnetometer, a climate station, and the Mars Surface Composition Detector, allowing it to perform in situ geological and environmental surveys of the landing site.4
The mission’s primary objectives are to study Martian topography and geological structures, investigate soil characteristics and the distribution of water ice, analyze the composition of surface materials, and examine the atmosphere, ionosphere, and internal physical fields of the planet. These goals are pursued through complementary roles: the orbiter conducting a global survey from space, while the rover focuses on detailed exploration of the Utopia Planitia basin, a region with geological evidence suggesting past water activity.2
Tianwen-1 has achieved several major milestones. The Zhurong rover became the first to explore southern Utopia Planitia, successfully driving across the plains and conducting high-resolution surveys well beyond its planned 92 Martian-day mission. Meanwhile, the orbiter entered a stable relay orbit to transmit rover data and later shifted to an elliptical orbit to continue its global mapping for one Martian year.4-5
The mission demonstrated a range of technological breakthroughs, including deep-space navigation, entry–descent–landing systems, autonomous rover operations, and integrated orbiter–lander–rover mission design.4
The Discovery: Evidence of an Ancient Martian Ocean
The Zhurong rover’s landing site lies within the Vastitas Borealis Formation, a geological unit long thought to preserve traces of past water activity. High resolution mapping of ridges, troughs, mesas, and rampart craters reveals a landscape shaped by both volcanic processes and volatile rich deposits.6
Among the most striking observations are ridge like landforms, polygonal terrains, and terrace structures that may correspond to the remains of ancient shorelines. Geomorphologic analysis shows linear ridges that resemble inverted stream beds or eroded dikes, as well as terrace like slopes that suggest episodic water levels once stood across the region. In addition, layered sediments and the morphology of rampart craters are consistent with impacts into ice rich or muddy substrates, reinforcing the role of subsurface volatiles.1, 6
Crater counting indicates that the surface of Utopia Planitia dates to approximately 3.3 to 3.5 billion years ago, coinciding with the Late Hesperian epoch when liquid water was more stable on Mars.
Earlier missions, such as Mars Global Surveyor and Mars Reconnaissance Orbiter, had proposed the existence of northern oceans on the basis of topographic and radar evidence, yet these interpretations were debated. The Tianwen-1 mission provides direct in situ confirmation that the geomorphologic features of Utopia Planitia are compatible with coastal processes, lending strong support to the long-standing ocean hypothesis.1
Scientific Implications: Climate, Water, and Potential Life
The shoreline like features documented in Utopia Planitia point to the existence of a stable hydrosphere on ancient Mars, where large volumes of liquid water may have pooled within its northern basins. This evidence strengthens models of a warmer and wetter planet, challenging earlier interpretations of Mars as a world that was perpetually cold and dry.6
If this region once hosted an ocean, it could have provided an environment conducive to microbial life. Shallow marine settings, together with volcanic heat sources inferred from magmatic dikes, may have supported hydrothermal systems, which on Earth are recognized as natural incubators of life.6
The discovery of aqueous sediments further increases the scientific value of Mars sample return missions. Sedimentary deposits near possible shorelines are promising targets for the preservation of biosignatures, organic molecules, and isotopic markers of past habitability. In this way, the Tianwen-1 findings provide a crucial foundation for site selection in Tianwen-3, China’s forthcoming Mars sample return mission.6
Commercial and Technological Relevance
The mapping of volatile rich regions such as Utopia Planitia carries significant implications for the future of space resource utilization. Subsurface ice deposits identified in this region could one day serve as a critical supply of water for human explorers or be converted into fuel to support long duration missions.7
The Zhurong rover also demonstrated advanced autonomous mobility, successfully navigating across dust covered and uneven terrain, an achievement that highlights technological progress in robotics and artificial intelligence systems designed for extreme environments.7
Beyond Mars exploration, the imaging, radar, and sensor technologies developed for Tianwen-1 offer valuable applications on Earth. These include improvements in remote sensing, subsurface imaging, and materials analysis, with potential benefits ranging from mineral exploration to climate monitoring. In this way, Tianwen-1 contributes not only to planetary science but also to technological innovation with tangible commercial relevance.8
Global Collaboration and Competitive Edge
The success of Tianwen-1 has firmly established China as a leading player in planetary science, delivering datasets on Martian geology at both global and local scales that surpass many earlier missions in scope and resolution.
At the same time, the mission’s findings in Utopia Planitia place China within a dynamic landscape of exploration where NASA’s Perseverance rover continues its investigations in Jezero Crater and the European Space Agency advances the ExoMars program. In this context, Tianwen-1 represents both a source of competition and an avenue for collaboration. The sharing of complementary datasets could greatly accelerate discoveries in Martian climate, geology, and the search for biosignatures.8
Beyond the scientific community, international aerospace firms, sensor developers, and artificial intelligence companies stand to benefit from partnerships with the China National Space Administration, using Tianwen-1’s data as a foundation for technology transfer and new innovations.8
Future Outlook: Mars Exploration and Commercial Frontiers
The CNSA is advancing preparations for Tianwen-3, scheduled for launch around 2030, with the goal of returning samples from one of three candidate landing regions: Amazonis, Chryse, or Utopia Planitia. To ensure mission safety, comprehensive dust storm risk assessments are already being conducted to refine landing scenarios.9
Looking further ahead, exploring Mars’ subsurface oceans or icy reservoirs will demand significant technological progress, including high-power ground-penetrating radars capable of probing depths beyond 500 meters, precision landing systems able to target rugged coastal or glacial terrains, and autonomous drilling and sampling equipment designed to recover buried sediments.9
Meeting these challenges requires not only new tools but also new approaches. Investigating potential Martian coastlines will depend on breakthroughs in propulsion, autonomous robotics, scientific instrumentation, and planetary protection protocols. By fostering broad interdisciplinary collaboration, humanity can move closer to a fuller understanding of Mars, laying the groundwork for a sustainable human presence on the Red Planet.
Want more on Mars? Check the latest on Perseverance
References and Further Studies
- Wu, X.; Liu, Y.; Zhang, C.; Wu, Y.; Zhang, F.; Du, J.; Liu, Z.; Xing, Y.; Xu, R.; He, Z., Geological Characteristics of China's Tianwen-1 Landing Site at Utopia Planitia, Mars. Icarus 2021, 370, 114657.
- Zou, Y.; Zhu, Y.; Bai, Y.; Wang, L.; Jia, Y.; Shen, W.; Fan, Y.; Liu, Y.; Wang, C.; Zhang, A., Scientific Objectives and Payloads of Tianwen-1, China’s First Mars Exploration Mission. Advances in Space Research 2021, 67, 812-823.
- Tan, X.; Liu, J.; Zhang, X.; Yan, W.; Chen, W.; Ren, X.; Zuo, W.; Li, C., Design and Validation of the Scientific Data Products for China’s Tianwen-1 Mission. Space Science Reviews 2021, 217, 69.
- Li, C.; Zhang, R.; Yu, D.; Dong, G.; Liu, J.; Geng, Y.; Sun, Z.; Yan, W.; Ren, X.; Su, Y., China’s Mars Exploration Mission and Science Investigation. Space Science Reviews 2021, 217, 57.
- Huang, H.; Wang, X.; Chen, Y.; Zhang, Q.; Zhao, F.; Ren, X.; Zeng, X.; Yan, W.; Chen, W.; Liu, B., Observations and Interpretations of Geomorphologic Features in the Tianwen-1 Landing Area on Mars by Using Orbital Imagery Data. Earth and Planetary Physics 2022, 7, 331-346.
- Wan, W.; Wang, C.; Li, C.; Wei, Y., China’s First Mission to Mars. Nature Astronomy 2020, 4, 721-721.
- Zhu, Q.; Wang, W.; Li, S.; Li, Z.; Cai, C.; Qin, J., High-Reliability and High-Precision Braking and Capture Control Technology of Tianwen-1 Probe. Space: Science & Technology 2024, 4, 0125.
- Zhu, F.; Zhang, Y.; Zheng, Y.; Guo, S.; Hua, B.; Liu, Y.; Wu, F.; Li, L.; Chen, J.; Dong, C., Design and Verification of Multi-Functional Obstacle Avoidance Sensor for the Tianwen-1 Mars Probe. Space Science Reviews 2023, 219, 42.
- Tian, Y.; Li, B.; Rong, Z.; Qu, S.; Chen, S., Martian Dust Storm Spatial-Temporal Analysis of Tentative Landing Areas for China's Tianwen-3 Mars Mission. Earth and Space Science 2024, 11, e2024EA003634.
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