Long March 5B Y3 carrier rocket, carrying Wentian lab module blasts off from the Wenchang Space Launch Center in Wenchang in southern China's Hainan Province. (Photo: AP)

In a major milestone for China's space program, a new scientific lab docked with its under-construction space station, Tiangong, bringing it closer to competition. The Wentian module docked with Tiangong station’s main Tianhe living module at 3:13 a.m. Monday, the China Manned Space Agency said.

The second of three modules to its permanent space station, Wentian was launched onboard China's most powerful rocket, the Long March 5B from the Wenchang Space Launch Center on the southern island of Hainan. The spacecraft reached its destination after travelling for nearly 13 hours post-launch.

Space agency staff, seen on the live feed observing the progress of the launch from a control room, cheered and applauded when the Wentian separated from the rocket about 10 minutes after the launch. The launch was "a complete success", CCTV reported shortly after.

The Wentian is designed for science and biology experiments, and the 23-ton lab module is heavier than any other single-module spacecraft currently in space, according to the state-owned Global Times. It will be followed by a second lab module, the Mengtian, due to be launched in October. Three astronauts are currently living in the core module on a six-month mission and oversaw the Wentian’s arrival and docking.

This was the third such launch since the Chinese space station entered its construction phase. It was preceded by the Tianzhou-class cargo spacecraft and the Shenzhou-14 crewed spacecraft. China began constructing the space station in April 2021 with the launch of the Tianhe module, the main living quarters, in the first of 11 crewed and uncrewed missions in the undertaking.

WHAT IS CHINA'S WENTIAN MODULE?

The Wentian lab module, 17.9 meters (59 feet) long, will be where astronauts can carry out scientific experiments, along with the other lab module yet to be launched - Mengtian ("Dreaming of the Heavens"). Wentian features an airlock cabin that is to be the main exit-entry point for extravehicular activities when the station is completed.

It will also serve as short-term living quarters for astronauts during crew rotations on the station, designed for the long-term accommodation of just three astronauts. The Wentian is designed for science and biology experiments, and the 23-ton lab module is heavier than any other single-module spacecraft currently in space, according to the state-owned Global Times.

Meanwhile, Mengtian module is expected to be launched in October and, like Wentian, is to dock with Tianhe, forming a T-shaped structure. The completion of the structure, about a fifth of the International Space Station (ISS) by mass, is a source of pride among ordinary Chinese people and will cap President Xi Jinping's 10 years as leader of China's ruling Communist Party.

China’s space program is run by the ruling Communist Party’s military wing, the People’s Liberation Army, and has largely proceeded with the Tiangong program without other nations’ assistance. The US excluded China from the International Space Station because of its military ties.