Tianwen-3

Tianwen-3
天问三号

Mission type	Mars sample return
Operator	CNSA
Spacecraft properties
Manufacturer	CAST
Start of mission
Launch date	2028 (planned)
Rocket	Orbiter/Earth-returner: Long March 5 Lander/ascent-vehicle: Long March 5
Launch site	Wenchang
Tianwen program

Tianwen-3 (Chinese: 天问三号) is a planned Mars sample-return mission by China which would send two spacecraft (an orbiter/Earth-returner and a lander/ascent-vehicle) via two separate launches to Mars. Together, the two spacecraft will seek to obtain samples of Martian rocks and soil and then return the cached samples to Earth. The mission is scheduled to launch in 2028.

Overview

In summer 2022 during a deep space exploration technology forum held at Nanjing University, Sun Zezhou, chief designer of the Tianwen-1 mission, detailed plans for the mission based on a two-launch architecture. The mission constitutes part of the Tianwen series of space missions.

The current mission architecture envisions two launches around 2028 by the Long March 5 carrier rocket. One launch will send an orbiter/return-vehicle. A second launch will send a lander/ascent-vehicle.

Once the lander arrives on the Martian surface it will collect surface samples, via a drill on the lander and possibly an autonomous mobile robot with multiple legs. After several months on the Martian surface and after storing the samples collected by the lander and mobile robot, the ascent vehicle will launch from atop the lander and rendezvous with the waiting orbiter. The ascent vehicle will transfer the collected samples to the orbiter/return-vehicle, which will depart for Earth. The samples will be returned to Earth via an atmospheric reentry vehicle.

Preliminary landing sites for the Tianwen-3 mission.

The main goal of the mission is search for life signatures. In 2024, scientists identified 51 potential landing sites in line with the missions current engineering constraints (altitudes less than −3 km, latitudes from 17°N to 30°N, slopes less than 8°, and 'rock abundance' less than 10%): 1 in Amazonis Planitia, 12 in Utopia Planitia, and 38 in Chryse Planitia or Arabia Terra.

International Collaboration

On 11 March 2025, CNSA opened the Tianwen-3 Mars sample-return mission to potential international partners. International teams can propose "piggyback payloads requiring support from the Tianwen-3 spacecraft or independent scientific instruments" for inclusion on the spacecraft. 15 kilograms of mass has been allocated on the Tianwen-3 Earth-return spacecraft for potential international scientific payloads and another 5 kilograms are available for partner payloads on the Mars orbiter. Interested parties may submit proposals by 30 June 2025 with a final selection targeted for October 2025. Flight hardware for the selected payloads are to be delivered in 2027.

See also

• Planetary Exploration of China
• NASA-ESA Mars Sample Return