The astronauts Chen Dong, Liu Yang – China’s first woman in space – and Cai Xuzhe entered the module at 3.12pm on Thursday, after leakage tests and other preparations, and were interviewed by CCTV from what they called “a new home”.

“China space station, a home for the whole of mankind,” Liu told the millions of viewers back on Earth.

Looking back on her first mission 10 years ago to Tiangong-1, Liu said the current station is more spacious and comfortable to live in.

Mengtian docked at the core module Tianhe’s front port when it arrived on Tuesday after a 13-hour flight from the Wenchang Satellite Launch Centre in the southern province of Hainan.

Thursday’s operation involved rotating the 18-metre (59-feet) long, 23-tonne Mengtian by 90 degrees and connecting it to Tianhe’s lateral port, opposite its sister research module the Wentian.

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Liang Xiaofeng, a designer of the Tiangong’s electronics system, told the CCTV live-stream that he had been nervous about the transposition, which he described as “gymnastics in space”.

“Now I feel relieved, and I’m proud that so many years of hard work has come to a perfect ending,” he said.

Liang, from the China Academy of Space Technology, said the procedure had gone smoothly and “precisely as planned”.

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Mengtian’s deputy chief designer Li Guangxing, from the Shanghai Academy of Spaceflight Technology, said a mechanical arm on the research module grabbed on to Tianhe to secure it after detachment. The arm was then used to slowly rotate Mengtian and hook it up to its final destination.

Throughout the process, the space station was manoeuvred to maintain a vertical position to the Earth’s surface, taking advantage of gravity to help stabilise the craft, Li said.

As soon as the transposition was complete, Tiangong returned to its normal horizontal flight mode, he told CCTV.

A similar manoeuvre was performed in September when the equally massive Wentian was rotated and relocated to its permanent port on the space station.

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China embarked on its manned spaceflight programme in 1992, with the goal of a crewed space station in low-Earth orbit by this year.

A three-step strategy started with the crewed spacecraft known as the Shenzhou missions, followed by the mini space stations Tiangong-1 and Tiangong-2.

Construction of the three-module Tiangong was officially approved in 2010 but suffered a major setback in 2017, when a launch failure of China’s only heavy-lift rocket – the Long March 5B – delayed Tianhe’s departure by over a year.

China made up the lost time with an intensive series of launches. Nine missions have been carried out since April last year, using three different types of rockets to deliver modules, supplies and astronauts into orbit for the Tiangong’s construction.

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China grows rice, other plants in space as part of Tiangong station experiment

China grows rice, other plants in space as part of Tiangong station experiment

A major goal for the Tiangong is the support of more than 1,000 scientific experiments, many related to microgravity and cosmic radiation, over the next 10 years.

“We expect to ignite the very first flame on the Chinese space station by the end of this year,” Liu Yucheng, a combustion researcher at Tsinghua University, told CCTV’s English-language news channel CGTN this week.

Liu said the Tiangong is equipped with high-speed cameras which his team will use to visualise the combustion process and create a 3D structure of a flame in space.

Some projects – like the High Energy Cosmic Ray Detector – are still in development and will be delivered to Tiangong later. This will be mounted on the space station’s exterior to detect the most energetic particles in the universe with unprecedented precision.

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How China’s space programme went from launching satellites to building its own space station

How China’s space programme went from launching satellites to building its own space station

The cosmic ray detector is one of nine international projects chosen in 2019 to fly on the Tiangong under a collaborative framework between the China National Space Agency and the United Nations Office for Outer Space Affairs.

Zhang told CGTN that more than half of the team of over 200 scientists on the project are from Europe, with the rest from the Chinese mainland, Hong Kong and Taiwan.

“Each institute contributes its best technology so that we can build the best experiment in the world,” said Zhang, from the Institute of High Energy Physics in Beijing.

“We hope when it is delivered to the Chinese space station around 2027, it will be the leading experiment in this field for at least 10 years.”