Check out the details of China's Tianwen-2 asteroid mission

China's Tianwen-2 mission was launched in the early hours of Thursday, aiming to shed light on the formation and evolution of asteroids and the early solar system.

The Tianwen-2 mission aims to achieve multiple goals over a decade-long expedition: collecting samples from the near-Earth asteroid 2016HO3 and exploring the main-belt comet 311P, which is more distant than Mars.

A Long March-3B carrier rocket blasted off from the Xichang Satellite Launch Center in southwest China's Sichuan Province at 1:31 a.m. Beijing Time. And about 18 minutes later, the Tianwen-2 probe was sent into a transfer orbit from Earth to the asteroid 2016HO3, according to the China National Space Administration (CNSA).

This is the first time that this series of carrier rockets has carried out an Earth escape orbit launch mission.

The spacecraft unfolded its solar panels smoothly, and the CNSA declared the launch a success.

Shan Zhongde, head of the CNSA, said the Tianwen-2 mission represents a significant step in China's new journey of interplanetary exploration.

Despite the mission's long duration and significant risks, he said he hoped it would make groundbreaking discoveries and expand humanity's knowledge of the cosmos.

Known as a quasi-satellite of Earth, asteroid 2016HO3 orbits the sun and appears to circle around Earth as well, remaining a constant companion to our planet. Only seven quasi-satellites of Earth have been discovered so far.

"Asteroid 2016HO3 is approximately 18 million to 46 million kilometers from Earth," said Liu Jianjun, researcher with the National Astronomical Observatory of Chinese Academy of Sciences. "It's relatively closer to Earth compared to other asteroids."

"We know there are millions of small celestial bodies. There are only about 30,000 near-Earth asteroids, so choosing this one means it's truly one-of-a-kind," Liu said, adding that it's extremely rare.

Scientists believe studying this asteroid will offer critical insights not only into the asteroid's own formation and evolution, but also into the broader history of the sun and Earth. "This is the first time internationally that this type of a small celestial body will be explored," Liu said.

"Collecting samples from 2016HO3 means we will have traveled beyond the Earth-Moon system and, for the first time, brought back samples from interplanetary space, which represents a huge leap forward in our country's planetary exploration," he added.

Dubbed as "cosmic fossils," asteroids preserve critical information about the solar system's infancy, scientists say.

The second target, 311P, a celestial anomaly discovered in the main asteroid belt between Mars and Jupiter, occasionally spews out materials and resembles a comet with tails. Its discovery challenges astronomers' conventional understanding about comets, as the region is too close to the sun for a comet to retain volatile materials like water ice.

The Tianwen-2 mission is expected to advance understanding of the origins, evolution and characteristics of these two types of small celestial bodies, said Han Siyuan, deputy director of the CNSA's Lunar Exploration and Space Engineering Center and spokesperson for the Tianwen-2 mission.

The mission will focus on measuring the physical parameters of the two celestial targets, including their orbital dynamics, rotation, size, shape and thermal properties.

The mission will also investigate the topography, composition and internal structure of the two celestial bodies, and possibly study the materials ejected by the main belt comet, Han said.

After the samples are brought back to Earth, they will be analyzed to determine their physical properties, chemical and mineral composition and structural characteristics, he added.

The mission is a complex one, with the spacecraft journeying for about a year to reach its first target, during which it will perform deep-space maneuvers and mid-course corrections until it is about 30,000 km away from 2016HO3.

The probe will gradually approach the target, carrying out closer exploration by circling and hovering over the asteroid to determine the sampling area, with a strategy of flying and probing simultaneously.

After completing the sampling, the spacecraft will fly back towards Earth when a return capsule is expected to separate from the main probe and deliver the samples back to Earth by the end of 2027.

"We aim to run the first leg of the race well," China Aerospace Science and Technology Corporation's Wei Yuanming told CGTN.

The main probe will then continue its voyage to rendezvous with the more distant target, the main-belt comet 311P, to carry out further exploration.

The probe is equipped with an array of scientific instruments, including cameras, a visible and infrared imaging spectrometer, a thermal emission spectrometer, radar, a magnetometer, and analyzers for charged and neutral particles, as well as for ejected materials, according to the CNSA.

The mission aims to overcome key technological challenges, including sampling on a low-gravity celestial surface, high-precision autonomous navigation and control, as well as trajectory design, according to the CNSA.

(Sun Ye contributed to the story. Cover: An illustration of the Tianwen-2 mission. /VCG)