China's Tianwen 2 probe reaches target asteroid, starts scientific exploration

China's Tianwen 2 probe reaches target asteroid, starts scientific exploration

China's Tianwen 2 asteroid sampling spacecraft has successfully 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. The spacecraft reached a position about 20 kilometers away from the asteroid last week and started traveling alongside it.

Prior to reaching the asteroid, the Tianwen 2 probe had traveled around 1 billion kilometers in a 400-day interplanetary journey. 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 mission team used optical navigation data 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.

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 kilometers from the asteroid, achieving coplanar flight with the celestial body. It reached a position about 2,000 kilometers from the asteroid on June 19.

The 2016 HO3, also known as 469219 Kamo'oalewa, orbits the sun and 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.

According to the China National Space Administration, the probe will progressively conduct more detailed scientific exploration to acquire data on the asteroid's morphology, material composition, and internal structure, laying the groundwork for subsequent sample collection operations.