China is preparing to launch its highly anticipated Tianwen-3 mission around 2028, aiming to return samples from the surface of Mars to Earth.
This mission will build upon the success of previous Chinese space exploration efforts, such as Tianwen-1, which successfully deployed the Zhurong rover on Mars.
The announcement of Tianwen-3 was made by Liu Jizhong, the mission's chief designer, during the second International Deep Space Exploration Conference in Huangshan City, Anhui Province, on September 5, 2024. This ambitious mission marks a significant advancement in planetary exploration, with a specific focus on understanding the potential for life on Mars and unlocking the planet’s geological secrets.
Mission Objectives: Searching for Signs of Life on Mars
The Tianwen-3 mission has a primary scientific goal: to search for signs of life on Mars. This involves studying Martian soil and rock samples for chemical signatures that may indicate the presence of past or even present life. According to Liu Jizhong, the mission will prioritize landing in areas that are geologically significant and astrobiologically relevant. These potential landing sites include regions that may have once been home to water or other life-sustaining elements, such as Amazonis Planitia, Utopia Planitia—where the Tianwen-1 Zhurong rover landed—and Chryse Planitia.
Scientists believe that sedimentary formations, hydrothermal systems, and ancient lakes on Mars could have preserved biosignatures, making these locations prime targets for sample collection. By analyzing these samples in laboratories on Earth, researchers hope to gain unprecedented insights into Mars’ environmental history, geological evolution, and its capacity to support life.
The Tianwen-3 Mission Architecture: A Two-launch Strategy
Tianwen-3 will employ a complex mission architecture involving two launches from Earth, utilizing China’s powerful Long March 5 rockets. One rocket will carry a lander and ascent vehicle that will touch down on the Martian surface and collect samples. The second rocket will launch an orbiter and return module that will remain in Martian orbit to rendezvous with the ascent vehicle carrying the collected samples.
Once the lander collects Martian soil and rock samples, they will be loaded into the ascent vehicle, which will launch from the surface of Mars and meet the orbiter in space. This process will require precise navigation and timing to ensure the samples are safely transferred to the return module. The return module will then make the long journey back to Earth, delivering the samples for detailed analysis.
The mission may also include innovative technologies to increase the range and variety of sample collection. A helicopter and a six-legged robot could be deployed to gather samples from diverse locations beyond the immediate landing site, much like NASA's Ingenuity helicopter on Mars. These technologies will allow scientists to gather more varied and scientifically valuable materials for study.
Overcoming Challenges: Planetary Protection and Technical Hurdles
The Tianwen-3 mission faces several significant challenges, both in terms of the technology required and the need to adhere to international planetary protection guidelines. One of the major technical hurdles is the need to successfully launch samples from the Martian surface, a task that has never been attempted by any space agency. The ascent vehicle will need to overcome Mars’ gravity and atmospheric conditions, rendezvous with the orbiter, and transfer the samples in orbit—a feat of engineering precision.
Another critical aspect of the mission is ensuring planetary protection, which refers to preventing contamination of either Mars or Earth during the mission. China has committed to following international guidelines outlined by the Outer Space Treaty and the Committee on Space Research (COSPAR) to ensure that no harmful Earth-based organisms are introduced to Mars and that Martian material does not carry potential biological hazards back to Earth. This requires stringent sterilization of spacecraft and careful handling of samples during their return to Earth.
These challenges, while significant, represent opportunities for China to demonstrate its growing capabilities in space exploration and planetary science. The success of Tianwen-3 could pave the way for more complex future missions and deepen our understanding of Mars as a potential habitat for life.
International Cooperation and Shared Scientific Goals
China has emphasized that international cooperation will be a key aspect of the Tianwen-3 mission. The Chinese National Space Administration (CNSA) plans to collaborate with global scientists by sharing data, samples, and research findings from the mission. This approach is in line with China’s previous space endeavors, such as the Chang’e-5 lunar mission, which made samples of lunar soil available for international researchers.
The Tianwen-3 mission will also involve partnerships in the development and deployment of scientific payloads. By working with international partners, China aims to maximize the scientific output of the mission and ensure that the collected data benefits the global scientific community. This cooperation extends beyond the current mission, as China has also outlined plans for the future establishment of a Mars research station, which could serve as a hub for international Mars exploration and research.
The future of Chinese space exploration
The Tianwen-3 mission is part of China’s broader plans for planetary exploration. Following the success of Tianwen-1, which included the deployment of the Zhurong rover, and the upcoming Tianwen-2 mission to collect samples from a near-Earth asteroid, China has set its sights on more ambitious goals. In addition to Mars exploration, the Tianwen-4 mission, planned for launch around 2030, will target Jupiter, expanding China’s role in deep space exploration.
As China continues to make strides in space exploration, the Tianwen-3 mission represents a major step toward understanding Mars and its potential for life, while also strengthening international cooperation in space science.