China's Tianwen-3 Aims to Return Mars Samples by 2031

China's Tianwen-3 mission is progressing toward a planned 2028 launch that would bring the first Chinese samples of Mars back to Earth, according to the China National Space Administration. The mission aims to return roughly 500 grams of Martian material by 2031, using a spacecraft made up of a lander, an ascender, a service capsule, an orbiter and an Earth reentry module.

Hou Zengqian, the mission's chief scientist, told Chinese state broadcaster CCTV that Tianwen-3 is "progressing smoothly, with intensified efforts being made to overcome technical challenges," adding that the probe equipment has entered the prototype development phase. If the schedule holds, Tianwen-3 will launch on two Long March 5 heavy-lift rockets from the Wenchang Space Launch Site on Hainan island, within a Mars launch window that runs from December 2028 to January 2029.

Searching for potential signs of life on Mars is the mission's top scientific goal, Hou said at the 2026 International Deep Space Exploration Conference in Hefei. He told the state-run Xinhua news agency that Tianwen-3 will look for microbial traces resembling early life on Earth, while also allowing for unknown forms of life that may have emerged through Mars' distinct evolutionary history.

China expects to finalize the mission's landing site by the end of 2026, selecting among candidates based on geological age, a history of water activity, habitability and the potential for preserving biosignatures — traces that could indicate past or present life. Hou said analysis of the returned samples at microscopic, molecular and isotopic scales could deepen scientists' understanding of Mars' geology, environment and the conditions under which life may originate.

A planetary protection laboratory is planned for the first phase of Hefei's Deep-Space Science City, according to the Deep Space Exploration Laboratory (DSEL). Xinhua reported that the lab will run a two-way protection system covering sample sterilization, unsealing, processing and biological risk assessment, guarding both the returned Martian samples and Earth's biosphere; DSEL planning director Li Hang said China will follow the planetary protection policies of the Committee on Space Research.