Beijing (AFP)

They and she will stay six months in space, a record for China: three astronauts, including a woman, left very early Saturday for the site of the Chinese space station, to continue its construction.

Their Shenzhou-13 spacecraft was propelled overnight at 12:23 a.m. (4:23 p.m. GMT Friday) by a Long-March 2F rocket, from the Jiuquan launch center in the northwestern Gobi desert, according to live footage. by public television CCTV.

At about 350-400 km altitude, the three astronauts will stay in Tianhe ("Celestial Harmony"), the only module already in orbit of the three that will eventually constitute the space station.

What will the crew members do for six months?

They will have to continue building the station, check the various equipment, but also conduct scientific experiments, in particular by providing valuable information on how their body adapts to this long stay.

Astronauts will also perform two or even three spacewalks.

Their stay will double the record of duration for a Chinese manned mission, just set in September by the astronauts of the previous mission, Shenzhou-12, who had stayed three months in Tianhe.

"The reason for this extended stay is to gain experience in long-term missions", explains to AFP Erik Seedhouse, professor specializing in space operations at the University of Aeronautics Embry-Riddle in the United States. United.

How China is planning the development of its space station John SAEKI AFP

"The main difficulty for astronauts will be to maintain their muscle mass and reduce their bone loss" in a weightless environment that weakens organisms, he emphasizes.

- "Ripe enough" -

The new crew includes two men: Zhai Zhigang (55), who was the first Chinese to perform a spacewalk in 2008, and Ye Guangfu (41), whose first space flight is.

They will team up with Wang Yaping (41), who is taking part in a new manned mission, eight years after a first trip in 2013, which made her the second Chinese in space.

Known for having given during her previous stay a live physics course to 60 million schoolchildren thanks to a video link, she will repeat the experience during this mission.

Image from Chinese public television CCTV showing the three astronauts who boarded the Shenzhou-13 spacecraft, left to right Ye Guangfu, Wang Yaping and Zhai Zhigang, October 15, 2021 - CCTV / AFP

She will also become the first Chinese woman to perform a spacewalk.

"China is not going to reinvent the wheel" with Shenzhou-13, notes Chen Lan, analyst at GoTaikonauts.com, specializing in the Chinese space program.

"This will not be a big challenge for China as its technologies are now quite mature. But any operation in space is inherently a challenge ..."

This mission is the fifth of the 11 (inhabited and unmanned) that will be needed in total for the construction of the Chinese space station, which should be completed by the end of 2022.

Called Tiangong ("Heavenly Palace"), it will be similar in size to the former Soviet Mir station (1986-2001).

Its lifespan will be at least 10 years.

- Robot and GPS -

The other two modules constituting the station, named Mengtian and Wentian (laboratories) will be launched next year and docked in Tianhe.

They will make it possible to carry out experiments in biotechnology, medicine or astronomy.

The Chinese ambition to build a station was fueled by the American refusal to accept Chinese people on the International Space Station (ISS) - a collaboration between the United States, Russia, Canada, Europe and Japan.

For its part, the Chinese space agency in charge of manned flights (CMSA) again assured Thursday that foreign astronauts could go to Tiangong.

China has been investing billions of euros for several decades to catch up with other space powers.

In May, it became the second country, after the United States, to make a small robot evolve on Mars.

China also landed a machine on the far side of the Moon in early 2019 - a world first.

Last year, it had brought back lunar samples and finalized Beidou, its navigation system competing with the American GPS.

It placed its first sun observation satellite in orbit around the Earth on Thursday.

Looking further ahead, Beijing plans to send humans to the Moon (around 2030) and build a base there with Russia.

© 2021 AFP