China's Tianwen 2 probe reaches asteroid Kamo'oalewa, begins mapping ahead of sample collection

Arrival at the asteroid

After a journey of roughly 400 days and one billion kilometres, China's Tianwen 2 probe has reached the near-Earth asteroid Kamo'oalewa. The China National Space Administration (CNSA) announced that the spacecraft successfully approached to within 20 kilometres of the body and has begun scientific exploration. The probe first detected the asteroid in June and performed a control manoeuvre on 7 June at a distance of 30,000 kilometres, gradually closing in since then.

The probe has successfully approached the celestial body to within 20 kilometres and begun scientific exploration.

The target: a quasi-moon

Kamo'oalewa is a quasi-satellite of Earth, a rock only a few dozen metres across that orbits the Sun in near-lockstep with our planet. Some researchers suspect it may be a fragment of the Moon, ejected by an impact. Laboratory analysis of the samples, including isotope ratios, is expected to clarify its origin.

Sample collection and return

Tianwen 2 will now map the asteroid from close range and collect a small amount of material. Several methods are under consideration, including a brief touchdown similar to those used by Japanese and American missions, as well as an anchoring technique never before tested on a surface. The return capsule carrying the samples is scheduled to land on Earth at the end of 2027. If successful, China would become the third country, after Japan and the United States, to bring asteroid material back to Earth.

Extended mission and deep-space ambitions

After releasing the sample capsule, the main probe will continue to comet 311P in the asteroid belt. The overall mission is designed to last about ten years. The programme is part of Beijing's expanding deep-space agenda: in 2021, the Tianwen 1 mission landed a rover on Mars, and a Mars sample-return mission, Tianwen 3, is planned for 2028.