Searching for Signs of Life on Mars Is the Top Goal of China's Tianwen-3 Mission

China's Tianwen-3 mission is seeking evidence of whether life has ever existed on Mars, aiming to collect high-value Martian samples and conduct detailed analyses after bringing them to Earth, the mission's chief scientist Hou Zengqian told Xinhua. Searching for potential signs of life on Mars is the mission's top scientific goal, Hou said on the sidelines of the 2026 International Deep Space Exploration Conference, which opened in Hefei, the capital of China's Anhui province.

Tianwen-3, planned for launch around 2028, is expected to become the first Mars sample-return mission in human history. NASA's Perseverance rover has already collected shallow surface samples but relies on a follow-up mission to return them to Earth, while Tianwen-3 aims to accomplish both sampling and return in a single mission. China expects to finalize the mission's landing site by the end of 2026.

"The Tianwen-3 mission will look for microbial traces potentially similar to early forms of life on Earth, while also taking into consideration the possibility of unknown forms of life that may have emerged through Mars' unique evolutionary history," Hou said. Over the past half-century, 47 Mars exploration missions have been conducted worldwide, but sample-return and crewed missions to Mars have yet to achieve a decisive breakthrough.

Hou said Mars sample return is an extremely complex project, with landing-site selection, planetary protection and contamination control, and the identification of potential signs of life among its key challenges. China will build the world's first planetary protection laboratory to prevent terrestrial microorganisms from contaminating Mars while ensuring the safe isolation of returned samples.

Chinese scientists are also advancing a new-generation geological map of the entire planet, using data from the Tianwen-1 mission and multiple international sources alongside artificial intelligence for geological interpretation; version 1.0, at a scale of 1:5 million, is scheduled for completion by the end of 2028. "Regardless of whether signs of life are found, the returned Martian samples will have irreplaceable scientific value," Hou said.