China is preparing to make history with its upcoming Mars Sample Return mission, Tianwen-3, scheduled to launch in 2028. This ambitious project aims to collect Martian soil and rock samples and bring them back to Earth for detailed analysis, potentially answering one of humanity’s most profound questions; has life ever existed on Mars?
Mars, the red planet. (Credit : NASA)
The mission represents leap forward in planetary exploration. While several countries have successfully landed rovers on Mars, returning samples to Earth requires an entirely different level of technological complexity and international coordination. If successful, China would become the first nation to bring potentially biologically active material from another planet back to Earth.
Mars wasn’t always the cold, dry desert we see today. Studies suggest that Mars once had a dense atmosphere and a warm, moist climate early in its history, making it suitable for the emergence and development of microbial life. Like Earth, Mars sits within our Solar System’s habitable zone, the region where liquid water can exist on a planet’s surface and therefore potentially support life!
Scientists believe that if life ever emerged on Mars, it would likely have been microbial, similar to the extremophiles found in Earth’s harshest environments. These hardy organisms thrive in conditions that would kill most life forms, surviving in environments with extreme temperatures, radiation, or chemical compositions.
Preliminary landing sites for the Tianwen-3 mission (Credit : By Zengqian Hou, Jizhong Liu, Yigang Xu, Fuchuan Pang, Yuming Wang, Liping Qin, Yang Liu, Yu-Yan Sara Zhao, Guangfei Wei, Mengjiao Xu, Kun Jiang, Chuanpeng Hao, Shichao Ji, Renzhi Zhu, Bingkun Yu, Jia Liu, Zhenfeng Sheng, Juntao Wang, Chaolin Zhang, Yiliang Li)
The Tianwen-3 mission involves a complex two part operation. There will be two separate components; a lander which will land on the Martian surface to collect samples and an orbiter, which will wait in orbit around Mars to receive the samples and bring them back to Earth. The lander will drill two meters underground, a crucial depth because Mars’ surface is constantly bombarded with radiation and corrosive chemicals that destroy organic materials. Below this hostile surface layer, valuable signs of past or present life might still be preserved after billions of years.
The mission’s success depends on careful site selection so the team are searching for regions where liquid water likely existed in Mars’ early history, areas rich in essential nutrients, and locations where traces of microbial activity could have been preserved. This preparatory research is ongoing and represents one of the mission’s most critical phases.
Surprisingly, the greatest obstacle isn’t the technical complexity of getting to Mars and back, it’s what happens when the samples arrive on Earth. The greatest challenge is in the quarantining and monitoring required once these extraterrestrial materials arrive, a process known as planetary protection. To address the risk, they plan to construct a specialised facility near Hefei Institute of Physical Sciences where Martian samples will undergo comprehensive testing under strict isolation from Earth’s environment. The samples will remain quarantined until scientists can conclusively determine they contain no active biological agents that could threaten Earth’s biosphere.
The Hefei Institutes of Physical Science (Credit : Yen Tzu)
This cautious approach reflects the profound implications of the mission. While the risk of dangerous Martian microbes may be small, the potential consequences are too significant to ignore. Only after extensive safety testing will the samples be released to laboratories worldwide for detailed scientific analysis.
The Tianwen-3 mission builds on China’s previous Mars success. In 2021, China became only the second country after the United States to successfully land and operate a rover on Mars with its Zhurong rover. This achievement demonstrated China’s growing capabilities in interplanetary exploration. This mission represents more than just a technological achievement, it could fundamentally change our understanding of life in the universe. If the samples contain evidence of past or present Martian life, it would prove that life can emerge independently on different worlds, suggesting that life might be common throughout the universe.
Source : In search of signs of life on Mars with China’s sample return mission Tianwen-3