A Long March-5B Y3 carrier rocket, carrying Wentian lab module, blasts off from the Wenchang Spacecraft Launch Site in south China's Hainan Province, July 24, 2022. (Xinhua/Li Gang) 

China on Sunday launched Wentian, the first lab module of its space station. The new module will function both as a backup of the core module and as a powerful scientific experiment platform.

The Wentian module is 17.9 meters long, has a maximum diameter of 4.2 meters, and a takeoff mass of 23 tonnes, according to Liu Gang, deputy chief designer of the China manned space program's space station system with the China Academy of Space Technology.

The Long March-5B Y3 carrier rocket, carrying Wentian, blasted off from the Wenchang Spacecraft Launch Site on the coast of the southern island province of Hainan, according to the China Manned Space Agency.

The construction of China's Tiangong space station is expected to be completed this year. It will then evolve from a single-module structure into a national space laboratory with three modules -- the core module, Tianhe, and two lab modules, Wentian and Mengtian.

The Tianhe module was launched in April 2021, and the Mengtian module is set to be launched in October this year.