China launches third space station module to enable zero-G experiments

Launched on the back of a Long March-5B Y4 carrier rocket, the new module blasted off from the coastal Wenchang space base on the tropical island province of Hainan.

Known as Mengtian, the new module is expected to spend around 13 hours in flight before it reaches Tiangong. The space station’s first module, Tianhe, only began orbiting last year.

Three astronauts – two male and one female – are currently living aboard Tiangong and will help ensure that the docking procedure of the new module to the axial port at one end of Tianhe is completed successfully.

Mengtian weighs some 20 tons with a length of 17.9 metres and diameter of 4.2 metres.

One of its primary uses will be to provide a space for zero-gravity science experiments. It also has an airlock for exposure to the vacuum of space and a small robotic arm to support extravehicular payloads.

During the station’s lifetime, China is planning more than a thousand scientific experiments – from studying how plants adapt in space to how fluids behave in microgravity.

Tiangong is expected to remain in service for at least a decade and is a milestone for China’s space ambitions.

In November 2020, the International Space Station (ISS) surpassed its 20-year milestone of continuous human presence and has provided unique opportunities for research in space. But Nasa plans to retire the ISS by 2031 could leave Tiangong as the only operational space station in orbit.

This could precipitate a rise in the number of demands from international bodies to carry out space experiments. Nevertheless, once completed, the space station will only be one-fifth the mass of the ISS, which was built through an international collaboration of Russian, US and European agencies.

In July, China launched the Wentian laboratory module which is the largest single-module spacecraft currently orbiting the Earth.

Next December, China plans to launch Xuntian, a space telescope that will co-orbit with Tiangong in slightly different orbital phases to allow for periodic docking with the station.