What the Mengtian launch means for China’s space dreams

The launch of Mengtian – which means “dreaming of the heavens” – aboard a Long March 5B rocket from the Wenchang launch centre in Hainan was a serious showcase of China’s ability to put together a space station independent of the two big players, the US and Russia. 

The Mengtian is the final module of China’s Tiangong – the heavenly palace – space station and it successfully docked with the core structure on November 1, a day after its launch.  This was a key step in its completion by the year’s end and a landmark moment in the country’s space ambitions.

Here are five things to know about the space station and the module:

‘Equal player’

Tiangong’s completion would signal that “China is now an equal player in space with the United States, Russia and Europe”, AFP quoted analyst Chen Lan as saying. “In terms of scientific and commercial aspects, it is always good to see new players coming.... Competition will always speed up innovation.”

Bai Linhou, deputy chief designer from the space station system at the China Academy of Spacecraft Technology (CAST), told Chinese tabloid Global Times that “the China Space Station will always be an open platform for global cooperation, and China is drafting cooperation standards, for rendezvous, docking and payload installation, which will be released to the whole world.”

Short message communication system

Global Times reported that for the first time in China’s aerospace history, “the Mengtian carries a subsystem for short message communication services empowered by the home-developed BeiDou Navigation Satellite System (BDS)”.

“According to mission insiders,” Global Times wrote, “the subsystem comprises short message receiving and sending antenna and applications that are installed on portable terminals held by the taikonauts (Chinese astronauts). It is the first-time application and testing of the BDS system in the China Space Station.”

The subsystem will form a communication bridge between taikonauts and their loved ones on Earth via short messages and voice messages whenever they like, and will provide an emergency link to the Chinese space programme headquarters should there be a malfunction in other communication methods on board.

Scientific experimentation

China launched the core module Tianhe (Harmony of the Heavens) in April 2021, followed by the experimental module Wentian (Quest for the Heavens) in July 2022.

According to the South China Morning Post, Mengtian is “equipped with more research facilities and will support a range of physics experiments under microgravity”.

SCMP gives as an example the experiment to cool atoms “to the lowest temperature ever achieved by humanity” by using lasers to lower the temperature to 10 picokelvins, “which is less than a billionth of a degree above absolute zero (−273.15 Celsius).”

Mengtian carried scientific equipment that will be used to study microgravity and carry out experiments in fluid physics, materials science, combustion science and fundamental physics, the space agency said.

Its payload included “the world’s first space-based cold atomic clock system”, Chinese news agency Xinhua reported.

“If successful, the cold atomic clocks will form the most precise time and frequency system in space, which should not lose one second in hundreds of millions of years,” said Zhang Wei, a researcher at the Chinese Academy of Sciences.

Heaviest Chinese spacecraft

The Mengtian module weighs more than 23 tonnes at launch, making it “the heaviest spacecraft China has ever launched”, the Global Times reports.

“According to Liu Guoning, deputy chief designer of the scientific cabinet system at the Chinese Academy of Sciences (CAS)’ Technology and Engineering Center for Space Utilization, it [the Mengtian] will be China’s largest comprehensive space experiment platform within the next decade,” it reported.

Once completed, the Tiangong space station is expected to have a mass of 90 tonnes –– around a quarter of the ISS –– or similar in size to the Soviet-built Mir station that orbited Earth from the 1980s until 2001.

In memory of Qian Xuesen

The South China Morning Post pointed out that the launch date of the Mengtian module coincided with “the anniversary of the death of Qian Xuesen, known as the father of China’s rocket programme, who died on October 31, 2009”.

After his studies in the US, Qian received security clearance “to work on classified weapons research [in the United States] … and by the end of [WWII] he was one of the world’s foremost experts on jet propulsion.”

Britannica reports that the US-educated Qian was caught up in the McCarthy era’s Red scare, and was kept under house arrest in the 1950s. Chinese authorities negotiated for his release, and upon his return to his homeland he “received a hero’s welcome”.

While he did not develop “any specific missile, rocket engine or satellite”, Qian earned the nickname “the father of Chinese aerospace” because, as Britannica puts it, “he personally trained the first generation of revolutionary China’s aerospace engineers.”