Three astronauts have blasted off from the Jiuquan Satellite Launch Centre in the Gobi Desert on a historic journey to China’s work-in-progress space station.

They are headed for the core, initial module of the Tiangong (Heavenly Palace) space station to do various tasks over the next three months.

The crew are led by 56-year-old Nie Haisheng, with another veteran Liu Boming, 54, and 45-year-old Tang Hongbo, who is on his first trip into space.

Niu and Liu, who have participated in previous space missions, are older than previous Chinese astronauts, including the country’s first, Yang Liwei
, who went into orbit at the age of 38 nearly two decades ago.

The Shenzhou-12 mission is the latest stage in China’s ambitious plans to be the only country to own and run its own space station, expected to be completed less than two years from now. Tiangong will rival the International Space Station (ISS) which is backed by the United States, Russia, Europe, Canada and Japan.

Speaking at a press conference on Wednesday, Nie made no secret that the mission is closely tied with China’s ambition to become a world-leading space power.

“This mission will be the first manned flight as part of the China space station’s construction. I’m very fortunate to kick off the first leg of the space station’s construction and I have many hopes,” he told reporters at the Jiuquan launch centre.

“China’s space exploration development has crystallised the Chinese people’s thousand-year dream of flying to the sky, and added a heroic chapter to the 100-year history of struggle of the [Chinese Communist] party,” Nie said, who has been a party member for more than three decades.

The three astronauts are all former air force pilots and follow 11 other Chinese citizens to have gone into space, including Yang, who did so in 2003.

Yang, now deputy director general of China’s manned space programme, has said that the age of the crew did not matter.

“We have given them some help to help them better adapt to this flight. I think [their age] is not a problem for the mission,” he said in an interview with state television.

Yang said the work awaiting the astronauts would be extremely challenging and complex but they had trained hard to complete the tasks.

“The content of physical training has increased a lot, six or seven hours in a session for activity that will take place outside the spacecraft,” Yang said, adding that after some drills the crew barely had the strength to hold their chopsticks.

The core Tianhe module is 16.6 metres long and 4.2 metres across at its widest point. Inside, the astronauts will have to test equipment and technology new to not only China’s space programme but also the world. Some technology, including ion thrusters – a kind of electric propulsion – has never been used before in a manned space flight.

The station’s construction work also means the three men will have to spend a lot of time on spacewalks, testing their physical strength to the limit.

The module has numerous tools to help ease the astronauts’ workload, including a giant robotic arm that can move to virtually any location on the space station’s surface. It can pass a tool or part to an astronaut, or carry him or her from one place to another.

The Chinese spacesuits also have some new features so the crew feel more comfortable and their movements are easier.

China initially hoped to send its astronauts to the ISS, which was launched in 1998, but the US rejected the request.

China’s space station programme has in part been driven by that rejection, according to Chinese space officials.

It is hoped the push into space will add wealth to the nation. And it is thought that when the ISS is retired in the next few years, Tiangong will be the largest artificial structure in space.

China’s astronauts have trained with their counterparts in Europe to work together on the Chinese space station. China has also signed a contract with Russia to jointly engage in manned space activities and build a base on the moon.

China has said it will help developing countries train their own astronauts and will welcome them to its space station.