National China The Space Agency’s Tianwen-2 asteroid probe successfully reached the asteroid Kamo’oalewa, which orbits the Sun in a path almost identical to the Earth’s motion.
After multiple orbit adjustments in deep space, it first detected Kamo’oalewa on June 6, 2026. On July 2, it successfully captured the first-ever images of Kamo’oalewa from a distance of approximately 20 kilometers. This achievement comes at the end of a 400-day journey covering a distance of approximately 1 billion kilometers.
Kamo’oalewa is the most stable of Earth’s known quasi-satellites, and because it orbits the Sun in nearly Earth-synchronous motion, 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 within a restricted time. If it manages to collect samples, it will release them in a capsule during its 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 when collecting samples. Because the probe’s orientation must be precisely adjusted when taking images, taking advantage of such restricted capabilities is an extremely tough task. Tianwen-2 plans to conduct more detailed scientific observations of Kamo’oalewa’s shape, material composition and internal structure.
If the mission is successful, it will be another achievement in asteroid sample return, following Japan’s Hayabusa and Hayabusa2 missions – the first to return asteroid samples to Earth – and NASA’s OSIRIS-REx mission. Material from tiny celestial bodies orbiting near Earth may provide one of the few clues to understanding the formation of the solar system, including Kamo’oalewa.
“It is highly likely that it contains primary information from the early formation of the Solar System and is of great scientific value in studying the composition of early material, formation processes and evolutionary history,” explains Han Siyuan, deputy director of the Lunar and Space Exploration Engineering Center and spokesman for the Tianwen-2 mission.
Scientists have previously theorized that Kamo’oalewa it is a fragment of the detached Moon as a result of an asteroid impact millions of years ago, was widely accepted until recently. This is because the spectrum of the reflected delicate closely resembles that of silicate minerals found on the lunar surface. Simulations also confirmed this theory.
However, in May, an international research team – including the Chinese Academy of Sciences – published article questioning this leading hypothesis. A reanalysis of available data showed that the central wavelength of the absorption band – the point at which delicate weakens at a given wavelength – matches the characteristics of LL chondrites (a type of meteorite with low iron and metal content).
The research team conducted an experiment in which they irradiated LL chondritic meteorite powder with a laser to simulate space weathering caused by solar wind and micrometeorites. The results closely matched Kamo’oalewa’s observational data. Scientists assume that Kamo’oalewa probably moved to the vicinity of Earth from the Flora family – a group of celestial bodies in the asteroid belt.
If Tianwen-2 successfully completes its sample collection mission and returns to Earth, it will likely aid answer questions about Kamo’oalewa’s origins. But first it must reach the asteroid’s surface.
This story originally appeared on WIRED Japan and was translated from Japanese.