China has successfully launched its first asteroid probe, Tianwen-2. If Tianwen-2 carries out its mission successfully, China will become the third country, after the United States and Japan, to collect samples from an asteroid.
On the 29th, the China National Space Administration declared the successful launch, noting that the solar panels of Tianwen-2 were deployed properly and that operations were proceeding smoothly.
According to China’s Xinhua News Agency, Tianwen-2 was launched by a Long March 3B rocket from the Xichang satellite launch center in Sichuan province around 1:31 a.m. that day. Eighteen minutes after the launch, Tianwen-2 entered its trajectory heading toward its exploration target, asteroid "469219 Kamo‘oalewa."
An asteroid is a small celestial body that orbits the Sun in a long elliptical path, believed to be remnants of planets formed in the early solar system. Unlike comets, which have volatile tails, asteroids do not. Kamo‘oalewa, with a diameter of 40-100 meters, is thought to hold information that can reveal details about the early solar system.
Tianwen-2 is scheduled to collect soil samples from asteroid Kamo‘oalewa in 2026. It will then return to Earth’s orbit in late 2027 and release a capsule containing the samples into the atmosphere. Previously, Japan's Hayabusa retrieved soil samples from asteroid Itokawa in 2010, Hayabusa2 collected samples from Ryugu in 2020, and the United States' OSIRIS-REx gathered samples from Bennu in 2023.
Soil samples collected from the asteroid will not only provide information about the early solar system but may also answer the hypothesis that Kamo‘oalewa is a celestial body that broke off from the Moon. U.S. researchers posited in 2021 that the spectral pattern of Kamo‘oalewa resembles that of lunar rocks, suggesting it may have originated from the Moon.
After dropping the Kamo‘oalewa samples to Earth, Tianwen-2 will embark on a secondary mission. It will explore the active asteroid 311P/PANSTARRS, located in the asteroid belt between Mars and Jupiter. Active asteroids move in asteroidal orbits but exhibit comet-like appearances by ejecting material.
Tianwen is an unmanned spacecraft developed by China for exploring solar system celestial bodies. China launched the Tianwen-1 Mars probe in 2020, which entered Martian orbit on Feb. 10, 2021, and landed on Mars on May 14, 2021. With this achievement, China became the third country, after the former Soviet Union and the United States, to successfully land a probe on Mars and communicate with Earth.
The Tianwen exploration missions will continue. Tianwen-3 is scheduled to launch in 2028 to return soil samples collected from Mars, while Tianwen-4 is expected to undertake a Jupiter exploration mission around 2030.