China’s Tianwen-2 spacecraft launches on May 29, 2025, beginning its year-long journey to a near-Earth asteroid. The spacecraft is expected to reach the asteroid in early July, take a sample from Kamo’olewa and send it back to Earth in a capsule.
If successful, the mission will be China’s first asteroid sample return mission. The sample will help confirm the asteroid’s origin and piece together clues to the early history of the Solar System.
earth’s half moon
Kamo’olewa was first discovered in 2016 by the Pan-STARRS 1 asteroid survey telescope in Haleakala, Hawaii. The space rock measures 131 by 328 feet (40 by 100 meters), which is comparable to the size of the Statue of Liberty.
Kamo’olewa does not reside in the Solar System’s main asteroid belt between Mars and Jupiter, but instead orbits the Sun at a much closer distance to Earth than other asteroids (about 9 million miles from our planet). After its discovery, Kamo’olewa (which translates to “oscillating celestial object” in Hawaiian) was found to be orbiting the Sun in conjunction with Earth. This makes it one of Earth’s seven known quasi-satellites.
Follow-up observations also revealed that the asteroid’s spectra matched lunar rocks from NASA’s Apollo missions. This discovery led scientists to believe that Kamo’olewa was actually a moon rock, an ancient piece of the Moon that was broken up by a large impact.
Enter Tianwen-2
Since its discovery, scientists have been fascinated by Kamo’olewa, as it may contain a piece of the Moon’s early history.
The China National Space Administration (CNSA) launched its Tianwen-2 mission to detect a near-Earth asteroid and trace its origin. Since its launch, CNSA has shared little information about the spacecraft’s whereabouts and the exact date of its asteroid rendezvous.
Earlier this month, the spacecraft was seen carrying out a series of small propulsive maneuvers that would have been used to set it up for a close approach to the asteroid. Following its encounter with Kamo’olewa, the spacecraft will spend several months conducting remote sensing observations to map the asteroid and pinpoint a potential sampling site, according to The Planetary Society.
Tianwen-2 is equipped with 11 science instruments to investigate its target and collect 20 to 100 milligrams of material from Kamo’olewa. The mission is expected to return the samples to Earth in April 2027, leaving a capsule with the material before heading off to explore another asteroid.
The Tianwen-2 mission is also designed to flyby the main belt asteroid 311P/PANSTARRS. The probe is expected to reach its second target in 2035.
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