China's third and final module docks with Tiangong space station

China's third and final space station module, Mengtian, has docked with the Tiangong space station after launching on Monday from a Long March 5B rocket at Wenchang Space Launch Center.

After eight minutes of flight, the module separated from the rocket and went into a low-Earth orbit before docking with the space station, said the China Manned Space Agency (CMSA). The 58.7-foot module originally arrived on the axial port at one end of module Tianhe, but will be repositioned while in orbit via robotic arm to a radial port on the side.

The 23-tonne module provides a second lab for the space station and is equipped with a hidden cargo airlock module so that cargo can be brought in and out of the cabin easily. On the outside of the airlock, the spacecraft is to have a platform for experiments with robotic arms.

The module also has a "releaser" for projecting cube satellites into space and 138 square meters worth of flexible solar panels. When combined with module Wentian, the duo is promised to generate around 1,000 kilowatt hours of electricity per day.

It also comes with 13 payload cabinets for experiments in microgravity and fluid physics, combustion and materials, including growing seeds and studying how spiders create webs, all in microgravity. And then there's the super-accurate cold atomic clocks: a hydrogen clock, a rubidium clock, and an optical clock.

State-sponsored media quoted Chinese Academy of Sciences director Zhang Wei as promising these clocks will be far more accurate than one launched on the Taingon-2 space lab in 2016. That clock had a margin of error of less than one second in 30 million years, said China's Global Times.

• Chinese booster rocket tumbles back to Earth: 'Non-zero' chance of hitting populated area
• Spent Chinese rocket booster splashes down over Southeast Asia
• Robotic arm on China's space station does a demo, swings out 20 degrees and back while holding cargo ship
• Forget everything you learned playing Lunar Lander: Chinese boffins reveal secrets of Chang'e 5 probe's touchdown

Mengtian also contains exercise equipment for the crew, similar to a rowing machine, according to the Chinese news outlet.

While Mengtian is the final module designed for the space station for now, Tiangong is scheduled to receive a space telescope named Xuntian in December 2023 for full operation by 2024. Xuntian will travel with Tiangong in slightly different orbits and have the ability to dock with it.

The space station is set to be used for 10 years by three taikonauts at a time but could very well be extended.

According to CMSA, Long March 5b got an upgrade which enables it to enter more accurately into orbit. However, its ability to control its descent back to Earth has not changed.

In May 2021, an anticipated uncontrolled landing of the rocket simultaneously concerned the world populace and inspired many memes before ultimately crashing down in the sea 45km from the Maldives.

In August 2022, it left debris over Southeast Asia before crashing down into the sea off the Philippines after putting Wentian into orbit.

NASA Administrator Bill Nelson issued stern words over both incidents and called for China to be more transparent about the rocket's path. ®