Tianwen 2 rendezvouses with target asteroid, set to begin surveys

China's Tianwen 2 asteroid sampling spacecraft rendezvoused with its target — a near-Earth asteroid called 2016 HO3 — and has begun to carry out scientific surveys, the China National Space Administration announced on Monday

According to the administration, the Tianwen 2 robotic probe reached a position about 20 kilometers away from 2016 HO3 last week and started traveling alongside the asteroid.

Prior to that, the spacecraft had traveled around 1 billion km in a 400-day interplanetary journey, the CNSA noted, adding that the probe will conduct detailed scientific explorations in a phased manner to acquire data on the asteroid's topography, material composition, and internal structure to support preparations for the sampling mission.

During Tianwen 2's approach to the asteroid, the probe obtained images of the celestial body — the CNSA released one such image taken by the craft's camera. While the position of the asteroid was previously determined solely by ground-based observations, the mission team used optical navigation data — which was collected during the approach process — to refine the asteroid's ephemeris and reduce its position error from hundreds of kilometers down to the kilometer scale, according to the administration.

The Tianwen 2 mission, which is China's first attempt to bring pristine asteroid samples back to Earth, was launched on May 29, 2025, when a Long March 3B rocket carrying the robotic probe blasted off from the Xichang Satellite Launch Center in Sichuan province.

En route to the asteroid, the probe carried out a series of operations, including deep-space maneuvers and mid-course corrections.

On June 6, the craft detected and identified the asteroid for the first time. The next day, it executed capture control at a distance of 30,000 km from the asteroid, achieving coplanar flight with the celestial body. It reached a position about 2,000 km from the asteroid on June 19.

The 2016 HO3, also known as 469219 Kamo'oalewa, orbits the sun and, therefore, is a constant companion of Earth. While it is too distant to be considered a true satellite of Earth, it is the best and most stable example to date of a quasi-satellite.

The Tianwen 2 will study the celestial body up close using a suite of 11 instruments — including cameras, spectrometers, and radars — before deploying special devices to collect surface substances.