Construction of the space station began last year with the launch of the first and largest of its three modules - Tianhe - the living quarters of visiting astronauts.
The modules Wentian and Mengtian are to be launched in July and October, respectively, docking with Tianhe to form a T-shaped structure.
Shenzhou-14 mission commander Chen Dong, 43, and team mates Liu Yang, 43, and Cai Xuzhe, 46, all from China's second cohort of astronauts, will live and work on the space station for six months before returning to Earth in December with the arrival of the Shenzhou-15 crew.
