Tianwen-2
Chinese asteroid and comet exploration mission
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Through Asteroid, Comet and Small Solar System body
On July 4, 2026 the spacecraft arrived at 469219 Kamoʻoalewa, a near-Earth asteroid that is currently a quasi-satellite of Earth. CNSA plans for Tianwen-2 to return samples from the asteroid during an Earth flyby in 2027 by ejecting a capsule into atmospheric entry. After the flyby, the probe is planned to rendezvous with the main-belt comet 311P/PanSTARRS in January 2035, and explore it with its 11 onboard instruments.
Overview
CNSA launched the Tianwen-2 probe using a Long March 3B carrier rocket on 28 May 2025 from the Xichang Satellite Launch Center in southwest China. The probe uses solar electric propulsion for maneuvering between its many objectives. It is planned to explore the co-orbital near-Earth asteroid 469219 Kamoʻoalewa and the main-belt comet 311P/PanSTARRS. The spacecraft rendezvoused with Kamoʻoalewa in July 2026 and is conducting remote sensing observations in orbit, while scouting for a sampling site. Tianwen-2 would carry out investigations at progressively lower altitudes from 20 kilometers, 3 km, 600 meters and down to 300 m from the asteroid’s surface before touching down or hovering to collect a sample of regolith. Explosives will be used to expose potential subsurface volatiles for detection.
The spacecraft will use both anchor-and-attach and touch-and-go methods to attempt collection of a sample. It would be the first time an anchor-and-attach method has been used on an asteroid, as both OSIRIS-REx and Hayabusa2 used touch-and-go.
Tianwen-2 will then return to Earth in 2027 to drop off a return capsule containing the sample and conduct a gravity assist maneuver to propel the spacecraft toward 311P/PanSTARRS. Remote sensing and in-situ measurements will be conducted at 311P/PanSTARRS for at least one year.
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History
In 2018, a deep space exploration roadmap covering the 2020–2030 timeframe was proposed by researchers at the Chinese Academy of Sciences, which included an asteroid exploration mission planned for launch around 2022 or 2024. Initially, the space probe was known as ZhengHe, with the name referencing the 15th century Ming Dynasty explorer Zheng He. In spring 2019, after a design study for the mission was carried out by the Chinese Academy of Space Technology (CAST), the CNSA began soliciting international proposals for scientific instruments to be carried on Tianwen-2.
In the planning stages, a nano-orbiter and nano-lander were proposed to be deployed to conduct remote sensing and sampling observations. Also, the original secondary target was 133P/Elst–Pizarro, and a flyby of an additional unnamed asteroid may also have been attempted.
Tianwen-2 was launched on 28 May 2025 from the Xichang Satellite Launch Center using a Long March 3B launch vehicle and was put directly on an escape trajectory from Earth, a first in the history of this launch vehicle. On 7 June 2026 the spacecraft performed an engine burn to rendezevous with the quasi-moon. Tianwen-2's close encounter with Kamoʻoalewa began on July 4, when the spacecraft approached within 20 kilometers of the asteroid.
Instruments
Tianwen-2 will incorporate several types of instruments, including wide/narrow angle multispectral and color cameras, a thermal emission spectrometer, a visible/near-infrared imaging spectrometer, a mass spectrometer, a magnetometer, and a charged/neutral particle and dust analyzer. International contributions to these payloads are being encouraged.
Scientific payload
Source:
- Visible Infrared Imaging Spectrometer
- Thermal Radiation Spectrometer
- Multispectral Camera
- Medium Field Color Camera
- Detection Radar
- Magnetometer
- Charged and Neutral Particle Analyzers
- Ejecta Analyzer
- Narrow Field of View Navigation Sensor
- Laser Integrated Navigation Sensor