China is preparing to dispatch a spacecraft to study Kamo'oalewa, a mysterious quasi-moon that scientists suspect could be a fragment blasted from the lunar surface. The Tianwen-2 mission, set to launch in the coming years, aims to rendezvous with and collect samples from the small asteroid, which travels in a near 1:1 orbital resonance with Earth. If confirmed as lunar debris, the rock would represent the first known quasi-satellite of terrestrial origin.
Kamo'oalewa, discovered in 2016, is one of eight known quasi-moons — asteroids that orbit the sun alongside Earth but are not gravitationally bound to it. Its unusual spectrum, distinct from typical near-Earth asteroids, closely matches that of the moon's silica-rich surface. This spectral fingerprint has led planetary scientists to hypothesize that a past impact on the moon ejected material that later settled into Earth's orbital neighborhood.
The Tianwen-2 spacecraft will carry a suite of instruments, including cameras, spectrometers, and a sampling arm, to analyze Kamo'oalewa's composition in detail. The mission is expected to spend several months orbiting the 100-meter-wide asteroid before attempting to collect regolith samples for return to Earth. Such material could provide direct evidence of the rock's lunar origin and shed light on the dynamics of impact ejecta.
If the hypothesis holds, it would rewrite our understanding of how material migrates between celestial bodies. It could also refine models of asteroid impact hazards by showing that some near-Earth objects are not primordial but recycled planetary fragments. The findings may even inform future efforts to extract resources from asteroids or to deflect those on collision courses with our planet.
Some researchers caution, however, that the spectral match could be coincidental, and that Kamo'oalewa might instead be a rare type of primitive asteroid. Only a sample return can settle the debate, and that remains years away.