China's Tianwen-2 spacecraft has transmitted the first image of Kamo'oalewa, a small asteroid that trails Earth through space, according to the China National Space Administration (CNSA). The agency said the probe had closed to a distance of 19 kilometers from the object by late June.
Kamo'oalewa is what scientists call a quasi-satellite: it orbits the sun but remains persistently close to Earth, swinging as near as 14 million kilometers and as far as 40 million kilometers away. It is one of only eight such objects discovered so far that shadow our planet's path around the sun. Researchers sometimes refer to these bodies affectionately as Earth's "mini moons."
The asteroid itself is modest in size, with an average diameter of about 20 meters, roughly the length of a city bus. It completes a full rotation every 28 minutes and was first spotted in 2016. Some studies have suggested Kamo'oalewa may actually be a fragment blasted off the moon by an ancient impact, though other evidence, including observations from the James Webb Space Telescope, has cast doubt on that idea.
Tianwen-2 launched on May 28, 2025, and spent the following 400 days covering approximately one billion kilometers to reach the asteroid. Its goal is to collect samples and return them to Earth in 2027, releasing them from a special reentry capsule during a close flyby of the planet.
Three ways to gather a sample
Mission planners built flexibility into the spacecraft's sampling equipment, giving it three possible approaches depending on conditions at the asteroid. One is a "touch-and-go" technique similar to methods used by NASA's OSIRIS-REx mission and Japan's Hayabusa2 probe. A second option, described as "anchor-and-attach," would have the spacecraft physically attach itself to the asteroid before drawing material from both the surface and subsurface. The third possibility involves a hovering method, in which a robotic arm extends from the spacecraft while it hovers above the asteroid to collect surface material.
The CNSA said Tianwen-2 will now carry out increasingly detailed scientific investigations to characterize the asteroid's shape, material composition and internal structure, laying the groundwork for the sampling operation to follow.
Once the mission delivers its Kamo'oalewa samples to Earth in 2027, Tianwen-2 will not be finished. The spacecraft is set to continue on to comet 311P/PanSTARRS, where it is expected to begin further observations and scientific study starting in 2035.