China Opens Tianwen-3 Mars Sample Return Mission to International Collaboration, Aiming for 2028 Launch

China's National Space Administration (CNSA) has announced an opportunity for international collaboration on its Tianwen-3 Mars sample return mission, scheduled for launch in late 2028. The mission aims to collect Martian samples and return them to Earth, seeking potential biosignatures to determine if life ever existed on Mars. CNSA offers up to 15 kg of mass on the Earth return orbiter and 5 kg on the Mars orbiter for international projects. Proposals should align with the mission's objectives, focusing on scientific innovation. Expressions of interest are due by June 30, 2025, with final selections in October 2027. The mission involves two Long March 5 rocket launches and aims to deliver samples to Earth around 2030 or 2031. Tianwen-3 will utilize technology from the Tianwen-1 rover landing and previous lunar sample return missions. The lander will carry instruments like the Mars Subsurface Penetrating Radar and the Raman and Fluorescence Analyzer for Mars. The mission targets potential landing zones such as Amazonis Planitia and Utopia Planitia, focusing on areas likely to preserve biosignatures. Sampling will include both surface and subsurface methods. If successful, Tianwen-3 could establish China as a leader in planetary exploration.