China's Tianwen-2 captures first close-up image of Earth's quasi-moon ahead of historic sample mission

China's Tianwen-2 spacecraft has captured the first close-up image of Kamo'oalewa, one of Earth's temporary "quasi-moons", after reaching the asteroid in preparation for what could become the world's first landing and sample collection mission on such an object. The newly released image, however, suggests the mission may be more challenging than originally anticipated because of the asteroid's small size, rapid rotation and fragile structure.

Tianwen-2 reaches Kamo'oalewa after 400-day journey

The China National Space Administration (CNSA) launched the Tianwen-2 probe from the Xichang Satellite Launch Center in southern China on May 28, 2025. Its primary destination is Kamo'oalewa, also known as 2016 HO3, a fast-spinning asteroid classified as a quasi-satellite of Earth.

Unlike the Moon, Kamo'oalewa is not gravitationally bound to Earth. Instead, it orbits the Sun alongside the planet, giving the appearance of accompanying Earth in space. Scientists say this is only a temporary arrangement, as the asteroid will eventually drift away from Earth's orbital path.


Although the CNSA had released little information about the mission since launch, it confirmed on Monday that Tianwen-2 entered orbit around Kamo'oalewa on June 7 after travelling more than 1 million kilometres over roughly 400 days.

First close-up image reveals challenging terrain

The announcement was accompanied by the first close-up photograph of Kamo'oalewa, taken from a distance of about 20 kilometres.

The image indicates the asteroid is approximately 40 metres across, placing it at the lower end of earlier estimates that suggested it could measure up to 100 metres in diameter.

Initial observations also suggest Kamo'oalewa is a rubble-pile asteroid, meaning it is made up of loosely bound material rather than a solid rock. Researchers had previously hoped the asteroid would have a stable surface suitable for an "anchor and drill" landing technique, but the latest findings indicate that approach may no longer be feasible.

Sampling mission faces added complexity

According to the CNSA, the asteroid's small size, unstable surface and rapid rotation will make sample collection significantly more difficult.

The newly released image also suggests there are few flat areas where the spacecraft could safely land.

"This greatly increases the complexity of the sampling process and the risk of the mission, making it much more difficult," CNSA representatives said in a report, according to the South China Morning Post.

An unverified mission timeline had suggested that sampling would begin on July 4. However, no such operation has been confirmed, indicating scientists may still be assessing how best to collect material from the asteroid.

The CNSA said Tianwen-2 will continue conducting detailed scientific observations to gather data on the asteroid's shape, composition and internal structure before attempting sample collection.

Mission could make China the third nation to return asteroid samples

If the spacecraft successfully collects samples, it will return them to Earth in November 2027 by releasing a capsule during a flyby. The capsule is expected to re-enter Earth's atmosphere at around 43,500 kmph.

A successful return would make China the third country to bring asteroid samples back to Earth, after Japan's Ryugu mission in 2020 and the United States' Bennu mission in 2023.

Scientists hope the material will provide insights into the early Solar System and help explain how water and organic molecules may have reached Earth. The samples could also help researchers better understand the seven other known quasi-moons that share Earth's orbit around the Sun.

Scientists hope samples will reveal asteroid's origin

Some researchers have proposed that Kamo'oalewa may be a fragment of the Moon that was ejected by an ancient meteor impact. Others have attempted to identify the lunar crater from which it may have originated.

Marco Fenucci, a mathematician at the European Space Agency's Near-Earth Object Coordination Centre who has co-authored several studies on Kamo'oalewa, previously said he hoped returned samples would help resolve the debate over the asteroid's origin.

Second mission targets unusual object beyond Mars

After completing its Earth flyby next year, Tianwen-2 will continue deeper into the Solar System for its second mission.

The spacecraft is scheduled to study 311P/PanSTARRS, an object beyond Mars that exhibits characteristics of both asteroids and comets, with its arrival planned for 2035.