"This is the sixth flight mission of China's manned spaceflight program this year and the last one in the construction phase of China's space station. The crew will work and stay in orbit for six months. The main purpose of this mission is to verify the space station's ability to support rotation between two crews of astronauts in orbit," said CMSA spokesman Ji Qiming. 

The Shenzhou-15 crew will work with the three Shenzhou-14 astronauts who have been on the space station since early June for about a week and are expected to return to earth in May next year. After accomplishing the successful launch mission, the space station project will now transit into an application and development phase which will last more than a decade.

In April 2021, China began construction of its space station with the launch of the Tianhe module, the main living quarters for astronauts. In July this year it launched Wentian, a laboratory module where scientific experiments will be performed. In October, it launched a second laboratory module named Mengtian. The completion of the space station, which is designed to last at least 10 years, will be a major milestone in China's space program.