Astronauts sent on mission to complete space station

In the second half of the mission, the Tianzhou 5 cargo craft and Shenzhou XV crew are scheduled to arrive at the massive space station.

The Shenzhou XIV and XV crews will meet inside Tiangong and work together for a short period before Chen's crew returns to Earth in December, the official said.

Previously, the Shenzhou XII and XIII three-member crews lived inside Tiangong. The Shenzhou XIII crew returned to Earth in mid-April.

In early May, the Tianzhou 4 cargo spacecraft was launched by a Long March 7 rocket from the Wenchang Space Launch Center, transporting nearly 6 metric tons of propellants and materials to the Tiangong station.

Pang Zhihao, a retired analyst from the China Academy of Space Technology and an independent spaceflight researcher, said on Sunday that the Shenzhou XIV crew's tasks are more demanding and challenging than those handled by the Shenzhou XII and XIII crews.

"They will not only need to monitor the docking of the Tianhe module and the two space labs, but also are responsible for assembling and configuring many instruments inside the labs," he said.

"What's more, it will be the first time that large components, namely the two space labs, will be linked with the core module. There will likely be technical uncertainties that the astronauts may have to deal with."

At the end of their journey, the crew will share their experience of operating and maintaining the station with the Shenzhou XV crew, he said.

Wang Ya'nan, editor-in-chief of Aerospace Knowledge magazine, said building and running a space station is a major symbol of a great space power.

This feat-along with other recent accomplishments, such as landing a rover on Mars-marks China's leading status in the international space arena, Wang added.

The Tiangong spacecraft is expected to operate for up to 15 years and scheduled to serve as a national scientific platform, space officials have said, noting that it will also be open to foreign astronauts.