The Chinese National The Space Administration’s Tianwen-2 asteroid probe successfully reached the asteroid Kamo’oalewa, which orbits the Sun on a trajectory nearly identical to Earth’s.

After undergoing multiple orbital adjustments in deep space, it detected Kamo’oalewa for the first time on June 6, 2026. On July 2, it successfully captured the first images of Kamo’oalewa from a distance of about 20 kilometers. This achievement comes at the end of a 400-day journey covering a distance of approximately one billion kilometers.

Kamo’oalewa is the most stable of the Earth’s known quasi-satellites and, because it orbits the Sun in a nearly synchronous motion with the Earth, it is considered a relatively accessible celestial body.

But landing on the asteroid (let alone collecting samples) will be a challenge. Kamo’oalewa has an average diameter of only about 41 meters and rotates at high speed. This means that the spacecraft must achieve stable contact and collect samples in a limited period of time. If it manages to collect samples, it will release them in a capsule during a flyby of Earth in November 2027.

Tianwen-2 is equipped with multiple cameras with different focal lengths. In addition to switching between a narrow field of view camera and a wide field of view camera depending on the situation, it also has a detachable camera that will be used during sample collection. Since the orientation of the probe must be precisely tuned when capturing images, taking advantage of these limited windows of opportunity is an extremely difficult task. Tianwen-2 plans to conduct more detailed scientific observations of the shape, material composition and internal structure of Kamo’oalewa.

If this mission is successful, it will mark another achievement in asteroid sample return, following the Japanese Hayabusa and Hayabusa2 missions (the first to return asteroid samples to Earth) and NASA’s OSIRIS-REx mission. Material from small celestial bodies orbiting near Earth could provide one of the few clues to understanding the formation of the solar system, including Kamo’oalewa.

“It is very likely to contain essential information from the early days of the formation of the solar system, and has great scientific value for studying the early composition of materials, formation processes and evolutionary history,” explains Han Siyuan, deputy director of the Lunar and Space Exploration Engineering Center and spokesperson for the Tianwen-2 mission.

Researchers have previously theorized that Kamo’oalewa is a fragment of the Moon carried away by an asteroid impact millions of years ago, something that has been widely accepted until recently. This is because the spectrum of the reflected light closely resembles that of the silicate minerals found on the surface of the Moon. Simulations also supported the theory.

However, in May, an international research team, including the Chinese Academy of Sciences, published a paper that casts doubt on this main hypothesis. A new analysis of the available data found that the central wavelength of the absorption band (the point where light weakens at a specific wavelength) matched the characteristics of LL chondrites (a type of meteorite with low iron and metal content).

The research team carried out an experiment in which they irradiated LL chondrite meteorite dust with a laser to simulate space erosion caused by the solar wind and micrometeorites. The results closely matched observational data from Kamo’oalewa. Researchers postulate that Kamo’oalewa likely migrated to Earth’s vicinity from the Flora family, a group of celestial bodies in the asteroid belt.

If Tianwen-2 successfully completes its mission to take samples and return to Earth, it will likely help answer questions about Kamo’oalewa’s origins. But first it has to reach the surface of the asteroid.

This story originally appeared on Japan wired and has been translated from Japanese.