The Tiangong-2 space lab, file photo. [Photo/CCTV]

BEIJING - China's first cargo spacecraft, Tianzhou-1, separated from Tiangong-2 space lab at 4:15 pm on Sunday.

At 3:29 pm on Sunday, the cargo ship started to separate from the space lab under orders from the ground. After separation, it operated at an orbit of about 400 kilometers above the earth.

Tianzhou-1 will continue to carry out experiments before it leaves orbit, and will gain experience for building and operating a space station.

Tianzhou-1 was launched on April 20 from South China's Hainan province, and it completed automated docking with the orbiting Tiangong-2 space lab on April 22. In the past five months, Tianzhou-1 has operated smoothly and completed various tasks.

Third in-orbit refueling

Tianzhou-1 cargo spacecraft and Tiangong-2 space lab completed their third and last in-orbit refueling at 8:17 pm Saturday. The third refueling, lasting about three days, confirmed the technical results from the second refueling.

The two spacecraft completed their first in-orbit refueling on April 27 and second on June 15.