Tianwen-2 Arrives at Earths Mini-Moon Kamoʻoalewa to Begin Sample Collection
Summary: Chinas Tianwen-2 spacecraft arrives at near-Earth asteroid Kamoʻoalewa to collect samples that may confirm or challenge its hypothesized lunar origin, with return planned for late 2027.
Chinas Tianwen-2 probe, launched on May 29, 2025 aboard a Long March 3B Y110 rocket from the Xichang Satellite Launch Center, has reached its target after roughly a year of cruise: the near-Earth asteroid (469219) Kamoʻoalewa (provisional designation 2016 HO3). This elongated body, approximately 40 to 100 meters across, completes one rotation every 28 minutes and is one of the most stable quasi-satellites of Earth, remaining in a nearby orbit for extended periods.
Tianwen-2 will collect and seal surface samples from Kamoʻoalewa for return to Earth, with the re-entry capsule expected to land in late 2027. This marks Chinas first asteroid sample return mission and a major milestone following the Chang'e-5 and Chang'e-6 lunar sample return campaigns. After completing the Kamoʻoalewa phase, the spacecraft will continue onward to main-belt comet 311P/PanSTARRS for further investigation.
The composition of Kamoʻoalewa has long been debated. A 2021 study led by Sharkey, Reddy, and others found its spectral signature closely matches lunar silicate minerals, suggesting it could be a fragment ejected by an ancient impact on the Moon. However, recent work from Ji Jianghui's team at the Purple Mountain Observatory, Chinese Academy of Sciences, has challenged this lunar origin hypothesis. The physical samples brought back by Tianwen-2 are expected to provide definitive evidence about where Kamoʻoalewa truly came from.