China's Tianwen-2 Probe Reaches Asteroid Kamo'oalewa and Begins Exploration

A Quasi-Moon as Target

Kamo'oalewa, also known as asteroid 2016 HO3, is a so-called quasi-satellite of Earth: the rock, only a few dozen meters in size, orbits the Sun nearly in sync with Earth and, according to research, lies roughly 40 million kilometers from Earth.

With the mission, China aims to map the asteroid from close range and collect a small amount of material. Various methods for sample collection are being considered, including a brief landing modeled on Japanese and American missions, as well as a previously untested anchoring procedure on the surface.

Samples for Research

According to the current plan, the return capsule with the samples is 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 material from an asteroid back to Earth. Analyses of the samples, such as isotope ratios, are expected to provide more clarity about the origin of the celestial body.

Some researchers suspect that Kamo'oalewa could be a fragment of the Moon hurled into space by an impact. This hypothesis, too, is to be tested with the help of the samples. After the encounter with the asteroid, the main Tianwen-2 probe is scheduled to continue on to comet 311P in the asteroid belt.

China's Deep-Space Agenda

The entire Tianwen-2 mission is designed to last about ten years. For Beijing, the program is part of an increasingly ambitious deep-space research agenda. Back in 2021, the Tianwen-1 mission successfully landed a rover on Mars; for 2028, a Mars sample-return mission called Tianwen-3 is also planned.

The approach to Kamo'oalewa marks an important milestone in the endeavor. Because the asteroid orbits the Sun almost in lockstep with Earth, it is considered a comparatively accessible target for a sample return and is therefore of particular scientific interest.