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China is moving closer to bringing the first samples collected on Mars back to Earth.
China says its Tianwen-3 mission is progressing toward a launch around 2028 and aims to bring at least 500 grams of Martian rock and surface material to Earth around 2031. The mission has now entered the prototype development stage, according to Tianwen-3 chief scientist Hou Zengqian.
If Tianwen-3 succeeds on schedule, China would become the first country to collect samples on Mars and return them directly to Earth. However, the 2031 date remains a target. The spacecraft is not yet complete, and the mission must overcome several difficult stages before any sample can reach Earth.
How Tianwen-3 will work
Tianwen-3 is being designed as a complex robotic mission involving two launches. China plans to use two Long March 5 heavy-lift rockets from the Wenchang Space Launch Center in Hainan province.
According to the China National Space Administration, the mission will include five main components:
- A lander that will reach the Martian surface
- An ascent vehicle that will carry the samples into Mars orbit
- A service module
- An orbiter that will receive the sample container
- A reentry module that will bring the samples to Earth
The two spacecraft groups will travel separately before working together at Mars. The journey from Earth is expected to take about seven to eight months. Mission planners expect surface and orbital operations near Mars to last about one year, with the full mission taking more than three years.
After collecting and sealing the samples, the ascent vehicle must launch from Mars and meet the orbiter in space. The sample container will then be transferred to the return spacecraft for the journey to Earth.
No mission has ever completed this full sequence at Mars. Launching from the Martian surface, locating another spacecraft in orbit, transferring a sealed container, and returning it safely to Earth will require several technologies to work correctly in sequence.
The mission will use three sampling methods
Tianwen-3 is expected to collect at least 500 grams, or about 1.1 pounds, of Martian material.
Current plans include surface scooping, drilling and collection with a small aerial vehicle. The drilling system is intended to reach as deep as two meters below the surface. This could give scientists access to material better protected from radiation and weathering than exposed surface rocks.
Tianwen-3 is not expected to carry a conventional rover. Instead, mission planners have proposed using a drone to collect material from locations within several hundred meters of the lander. These plans remain preliminary and could change as the spacecraft design develops.
Using several collection methods could improve the range of samples returned from a single landing area. Even so, the scientific value of the collection will depend heavily on where Tianwen-3 lands.
Chinese scientists initially studied more than 80 possible locations and later reduced them to 19. Mission leaders have said the landing-site selection process should advance further by the end of 2026.
The site must be safe enough for landing and takeoff, but it must also contain rocks or sediments that could preserve information about ancient water, climate and possible biological activity.
Searching for signs of Martian life
The mission’s main scientific goal is to search for evidence that life may have existed on Mars.
Researchers plan to examine the material for possible biological markers and other chemical or structural evidence. The samples could also help scientists investigate three broad questions:
- Did Mars ever contain life or conditions capable of supporting it?
- How did the planet’s water, atmosphere and climate change?
- How did Mars develop geologically over billions of years?
These questions are closely connected. Mars contains clear evidence of ancient rivers, lakes and water-driven geological activity. Scientists still do not know whether those environments ever supported living organisms.
Samples would let researchers use large, highly sensitive instruments that a rover cannot carry. Laboratories on Earth could examine the material at microscopic, molecular and isotopic levels. Scientists could also preserve part of the collection for future instruments and methods that do not yet exist.
A 2025 paper in Nature Astronomy described Tianwen-3’s central goal as collecting at least 500 grams of material and returning it around 2031 to support the search for signs of life and studies of Martian geology and habitability.
Finding organic material would not automatically prove that Mars once had life. Organic compounds can also form through non-biological processes. Any possible biosignature would need extensive testing, independent confirmation, and careful evaluation of other explanations.
China is preparing a secure laboratory
Returning material from Mars also creates strict contamination-control requirements.
China is planning a dedicated planetary-protection laboratory in Hefei’s Deep-Space Science City. The facility is intended to keep Earth organisms from contaminating the samples while also isolating the returned material from the wider environment.
It is expected to support the opening, processing, scientific examination, and storage of Martian samples. The facility will use a two-way protection system covering both sample cleanliness and biological safety.
This work is important even though there is currently no evidence that Mars contains dangerous organisms. Samples must remain as clean as possible if scientists are to determine whether any unusual chemical or biological signal came from Mars rather than Earth.
International instruments will join the mission
China has opened parts of Tianwen-3 to international cooperation.
The mission includes instruments developed with teams from Hong Kong, Macao, Italy and international scientific organizations. The planned equipment will study surface minerals, water isotopes, atmospheric loss, and other features of Mars.
An Italian laser reflector is expected to be placed on the surface, while several spectrometers and atmospheric instruments will operate from orbit. CNSA previously allocated up to 20 kilograms of spacecraft capacity for international payloads.
These partnerships could broaden the mission’s scientific output. However, details about access to the returned samples, international laboratory participation and long-term data sharing will remain important.
What happened to NASA’s sample-return plan?
NASA’s Perseverance rover has already collected and sealed carefully selected samples in Jezero Crater. The United States and the European Space Agency had planned a separate campaign to retrieve those tubes and bring them to Earth.
That plan became increasingly difficult because of its cost and complexity. Earlier estimates placed the total cost as high as $11 billion, while projected sample delivery moved well beyond the original early-2030s goal.
The US Government Accountability Office reported in 2026 that NASA’s Mars Sample Return program had started closeout activities. NASA had not decided how the most useful technologies would continue under future Mars programs. Before the closeout began, an alternative approach was estimated to return samples no earlier than 2035.
NASA still describes Mars sample return as a high scientific priority, and the Perseverance samples remain stored for possible retrieval by a future mission. However, the agency does not currently have a confirmed program and schedule to return them before China’s 2031 target.
This means the situation is not a simple race between two spacecraft with fixed launch dates. China has an active mission under development, while the future of NASA’s original retrieval campaign is unresolved.
A historic mission with major risks
Tianwen-3 could give China a leading position in planetary exploration. It would build on the country’s Tianwen-1 mission, which successfully entered Mars orbit and delivered the Zhurong rover to the surface in 2021.
Still, success is not guaranteed.
China must complete the spacecraft, choose a landing site, protect the samples from contamination, and launch during a suitable Earth-Mars window. It must then land safely, collect useful material, launch from Mars, complete an orbital rendezvous, and return the sealed container through Earth’s atmosphere.
A delay in the launch schedule could have a large effect because favorable Mars launch opportunities occur about once every 26 months.
If the mission remains on schedule and completes every stage successfully, Tianwen-3 could deliver the first directly collected Martian samples to Earth around 2031. The result would be more than a symbolic victory. It would give scientists new material to study Mars and search for evidence of whether another planet once supported life.
