Aims for Sample Return and Scientific Breakthroughs

China is planning to launch the Tianwen-3 Mars mission in 2028, with the goal of returning samples to Earth by 2031. This mission, led by chief scientist Hou Zengqian, represents a significant advancement in China's planetary exploration program. Unlike the Tianwen-1 mission, which utilized a rover, Tianwen-3 will employ a drone to collect samples remotely, reducing the risk of contamination from the probe's landing.

The mission's design incorporates three sampling methods to ensure a diverse collection of samples with high scientific value. These methods include surface soil shoveling, deep drilling, and drone-assisted grabbing. A notable aspect of the mission is the planned two-meter-deep drilling, which would be a first for Martian exploration. Previous missions, such as the US Perseverance rover, have only been able to collect shallow surface samples. Tianwen-3 aims to accomplish both sample collection and return within a single mission.

Hou emphasized that Tianwen-3 marks a shift from a primarily engineering-driven approach to a dual focus on both engineering and scientific objectives. The successful landing of Tianwen-1 demonstrated China's engineering capabilities. The next step is to define the scientific questions that Mars exploration aims to answer and to determine how to achieve these goals. The mission is expected to launch in 2028, take seven to eight months to reach Mars, operate on the planet for about a year, and then return to Earth, totaling over three years. The mission aims to return at least 500 grams of Martian samples.

The scientific goals of the Tianwen-3 mission include searching for potential signs of life on Mars, studying the planet's habitability evolution, and understanding its geological structure and evolutionary history. The team has narrowed down the candidate landing sites from over 80 to 19, with plans to further reduce the selection to three by 2026. The development of the probe is progressing through various stages, with the prototype stage already underway. The scientific mission team is actively using Mars observation data to conduct studies and advance the landing site selection process.