Tianwen: investigate planets and small bodies with different methods

Tianwen is the name used for China’s planetary-exploration missions, distinct from the Chang’e lunar program. CNSA coordinates the exploration effort with spacecraft developers, scientific institutions, instrument teams and ground networks. An exploration program can use different architectures as the destinations and questions change; a shared name does not make every mission a Mars rover.

Tianwen-1 launched in July 2020 and entered Mars orbit in February 2021. It carried an orbiter and a landing system containing the Zhurong rover. The mission combined broad orbital measurements with observations from a selected surface region. The separate elements had different instruments, trajectories and responsibilities, even though they traveled together during the interplanetary journey.

The landing system reached Utopia Planitia in May 2021. After deployment, Zhurong could investigate terrain, materials and the near-surface environment along its route, while the orbiter supplied a wider perspective and communication support. Instruments such as cameras, radar and spectrometers measure different properties and require their own calibration and interpretation.

The rover-and-lander image was obtained using a deployed remote camera. It shows the two vehicles on the surface, rather than an artist’s prediction or a photograph made by an astronaut. It does not reveal everything beneath the soil or establish whether life existed there. Those questions require evidence from appropriate instruments and comparison with alternative explanations.

Tianwen-2 launched on May 29, 2025, Beijing time. Its announced mission combines sampling the small near-Earth asteroid 2016 HO3, also called Kamoʻoalewa, with a later investigation of comet 311P. The launch is a completed milestone; obtaining, returning and interpreting samples are separate objectives that a launch report cannot establish as accomplished.

Sampling a small body poses a different problem from driving on Mars. Weak gravity changes how a spacecraft approaches and contacts the surface, and returned material needs a documented collection and handling history. Compare the two missions by tracing each science question through its measurement method. The program’s continuity lies in an exploration effort, while the hardware and evidence pathways change with the task.