Taking an important step in space exploration, the China National Space Administration (CNSA) launched, on May 28, 2025, its first mission to bring samples from an asteroid. The spacecraft, named Tianwen-2, was launched from the Xichang Satellite Launch Center in Sichuan Province of southwest China. It was carried into space by a Long March 3B rocket. This mission makes China the third country, after the US and Japan, to attempt for bringing asteroid material back to Earth.
Background
The concept of this mission emerged in 2018, when scientists of the Chinese Academy of Sciences outlined a 10-year (2020–30) roadmap for deep space exploration. The asteroid mission was a key part of that plan. Initially, the mission was called Zheng He, named after a famous 15th-century Chinese explorer. Later, it was renamed Tianwen-2, meaning ‘questions to heaven’. In 2019, after a detailed design study by the Chinese Academy of Space Technology (CAST), CNSA invited international researchers to propose instruments for the mission.
Purpose of the Mission
The Tianwen-2 mission is a dual-objective endeavour. Its first target is to collect samples from a near-Earth quasi-satellite asteroid named 469219 Kamo’oalewa. After this, the spacecraft would travel further into space to study a distant object, 311P/PanSTARRS, which has features of both an active-asteroid and a comet.
By doing this, China wants to learn more about the early history of our solar system. Scientists believe that studying about these asteroids and comets in space would help in understanding how planets and other celestial bodies were formed. This knowledge could also be useful for planetary defence, as it helps in planning how to detect and deal with potentially dangerous near-Earth objects (NEOs) in future.
The Asteroid Kamo’oalewa
Kamo’oalewa is a small, 40–100 metre-wide asteroid discovered in 2016 by the Pan-STARRS 1 telescope in Hawaii. It is located approximately 15 to 29 million kilometres from Earth. Though it orbits the Sun, it stays near Earth due to gravitational interactions, making it a quasi-satellite. Interestingly, the reflected light spectrum of Kamo’oalewa closely resembles lunar rocks, leading scientists to believe it may be a fragment ejected from the Moon during a massive impact.
Tianwen-2 is expected to reach Kamo’oalewa in July 2026. It would observe the asteroid closely using onboard instruments before collecting up to 100 grams of material. The sample collection period is scheduled to span from July 2026 through April 2027.
After collecting the samples, Tianwen-2 would store them in a return capsule. The spacecraft then would head back towards Earth. By November 2027, it would release the sample capsule into Earth’s atmosphere for recovery. After that, the spacecraft would perform a gravity manoeuvre to propel the spacecraft and continue its journey towards its second target 311P/PANSTARRS. The second target is anticipated to be reached in mid-2035.
Mission Phase 2: Studying 311P/PanSTARRS
The second target, 311P/PanSTARRS, is an object that behaves both like a comet and an asteroid. It was discovered in 2013 by Bryce T. Bolin using the Pan-STARRS telescope. It has six visible tails, according to the observations made by the Hubble Space telescope. The tails, are likely to be made of the rubble pile flying off due to the asteroid spinning at a very high speed. It orbits in the main asteroid belt between Mars and Jupiter and has a radius of about 240 metres. On April 19, 2018, observations based on light curvature suggested a possible satellite around 311P/PanSTARRS approaching 200 metres adding to the complexity of its structure.
Tianwen-2 is expected to reach 311P/PanSTARRS in the mid-2030s. Unlike with Kamo’oalewa, it would not land on 311P/PanSTARRS. Instead, Tianwen-2 would orbit it and study it in detail using its on-board instruments. This would help scientists understand the link between asteroids and comets and possibly how water and organic compounds came to Earth.
Innovative Sampling Techniques
Tianwen-2 would use several methods to collect material. One method is the ‘touch-and-go’ technique where the spacecraft briefly lands on the asteroid’s surface to collect samples. The similar method was used in earlier missions by Japan’s spacecraft, Hayabusa-2 and NASA’s spacecraft, OSIRIS-Rex, to collect surface material from asteroids. Another method is called the ‘anchor-and-attach’, where robotic arms would grab onto the asteroid and drill into its surface to collect material. This method has never been used before in any other space missions. A third approach may include hovering close to the surface while deploying small projectiles or gas jets to dislodge material.
A nano-lander and nano-orbiter will also be deployed on the asteroid for in situ characterisation of asteroid to conduct surface-level studies, seismic sensing, and local imaging, expanding the scientific value of the mission.
Instruments on Tianwen-2
Tianwen-2 has been equipped with 11 scientific instruments to carry out its tasks. These tools are designed to help scientists study asteroids and comets, in great detail and carry out imaging, sampling, and particle analysis.
Some of the main instruments include:
- Visible and Infrared Imaging Spectrometer
- Thermal Radiation Spectrometer
- Multispectral and Colour Camera
- Detection Radar
- Magnetometer
- Charged and Neutral Particle Analysers
- Ejecta Analyser
- Narrow Field Navigation Sensor
- Laser Integrated Navigation System
These instruments would help measure surface materials, detect dust and gases, and take high-resolution images.
In June 2025, CNSA released the first in-flight images captured by Tianwen-2, showing the spacecraft’s fully deployed solar panel from a distance of over 3 million kilometres.
China’s Long-Term Space Plans
Tianwen-2 follows China’s earlier success with Tianwen-1, its first Mars Mission. Tianwen-1 entered Mars orbit and landed on Utopia Planitia, after a six-month journey, in a region believed to contain underground water ice.
China has planned even more ambitious missions. Tianwen-3 is expected to be launched in 2028 to return with samples from the planet Mars. It is a mission, which no country has undertaken so far. The CNSA has announced that foreign countries and research institutions would be allowed to carry payloads of up to 20 kg (44 lb) on the orbiter and lander designated for Mars exploration.
After that, Tianwen-4 would explore the Jupiter system and possibly even reach Uranus.
These missions are a part of China’s long-term goal to become a major space power by the middle of the 21 century. With each mission, China is developing more advanced technologies in order to gain deeper scientific knowledge about the solar system.
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