Crew members of the Shenzhou XXI mission, who have spent nearly seven months on board the Tiangong space station, will return to Earth very soon, according to a statement released on Thursday by the China Manned Space Agency.

The three Shenzhou XXI astronauts — mission commander Senior Colonel Zhang Lu, spaceflight engineer Major Wu Fei and payload specialist Zhang Hongzhang — have completed all their assigned tasks and will fly back aboard the Shenzhou XXII crew ship, the statement said.

Ground recovery personnel at the Dongfeng landing site in the Inner Mongolia autonomous region, along with other relevant systems, have been preparing for their return, it added.

On Thursday, the Shenzhou XXI astronauts handed over control of the space station to their successors from the Shenzhou XXIII mission — mission commander and spaceflight engineer Colonel Zhu Yangzhu, spacecraft pilot Colonel Zhang Zhiyuan and science payload specialist Lai Ka-ying — who arrived at Tiangong on Monday.

A video clip published by the agency showed the two groups holding a simple handover ceremony on board the space station.

Zhang Lu said that he and his crew have been impressed by the teamwork and skills displayed by Zhu's team over the past three days, and he wished them great achievements. "We will wait for your triumphant return, and see you in Beijing," the Shenzhou XXI commander said.

In response, Zhu said that he and his crew are grateful to the outgoing astronauts for sharing every detail of their experience.

"We also appreciate your professionalism and dedication very much. You guys did your jobs very well. We will learn from your hardworking spirit and valuable experience, and will faithfully carry out our duties," he added.

The Shenzhou XXI team arrived at the space station on Nov 1 as part of China's 16th manned spaceflight and the 10th crewed mission aboard Tiangong.

Zhang Jingbo, a spokesman for the China Manned Space Agency, said the Shenzhou XXI astronauts have achieved good results in several fields, including space life science, materials science, microgravity physics, space medicine and new spacecraft technologies, with cooperation and support from scientists and engineers.

The Shenzhou XXII mission was originally designated to be a manned flight, but was changed into an unmanned emergency response mission in late November after space debris damaged the Shenzhou XX crew ship.