Long March 5B Y4 Rocket Safely Arrives at Wenchang Spacecraft Launch Site
Summary: On July 25, the Long March 5B Y4 rocket arrived at Wenchang launch site to assemble and test with the Mengtian lab module.
On July 25, 2026, the Long March 5B Y4 (CZ-5B Y4) launch vehicle successfully arrived at the Wenchang Spacecraft Launch Site in Hainan Province, China, marking another key milestone in the construction of the China Space Station. According to the China Manned Space Agency (CMSA), the rocket arrived in good condition after long-distance transport and will proceed with assembly and integration testing alongside the Mengtian laboratory module.
The Long March 5B is China's most powerful operational rocket in terms of low-Earth-orbit (LEO) payload capacity, capable of lifting approximately 25 tonnes to LEO. Featuring a unique two-stage-to-orbit configuration with four liquid-fueled boosters and a core stage, the rocket stands about 53.7 meters tall and was specifically developed to launch large space station modules. It has previously completed multiple successful missions for the China Space Station program, including the deployment of the Tianhe core module and the Wentian laboratory module.
The Mengtian lab module is the third and final major component of the China Space Station. Primarily dedicated to microgravity science research, the module is equipped with multiple experiment racks and an airlock舱 for deploying payloads and experiments. It is designed to support a wide range of scientific investigations, including space materials science and microgravity fluid physics experiments. Once Mengtian is successfully launched and docked, the T-shaped basic configuration of the China Space Station will be fully assembled in orbit.
Preparations at the Wenchang launch site are currently proceeding in an orderly manner. Assembly and testing of the rocket with the Mengtian module will be carried out according to schedule. The exact launch date has not yet been announced and is expected to be determined based on testing progress and weather conditions.