(Source: CGTN)

The Tianzhou-1 cargo spacecraft successfully completed automated docking with the orbiting Tiangong-2 space lab. The two vessels will orbit together for about two months, then Tianzhou-1 will orbit independently for about three months for further experiments.

The graphics shows the procedures of Tianzhou-1 automated docking with Tiangong-2 on April 22, 2017. (Xinhua/Lu Zhe)

The entire docking process lasted more than 5 hours.

It took two days for the Tianzhou-1 cargo spaceship to transition into rendezvous operations with the Tiangong-2 module.

The successful docking will kick start what is a two-month long combined operations project.

Technical personnel work at Beijing Aerospace Control Center to monitor the automated docking between Tianzhou-1 cargo spacecraft and Tiangong-2 space lab in Beijing, capital of China, April 22, 2017. The Tianzhou-1 cargo spacecraft, China's first cargo spacecraft, which was launched Thursday evening from Wenchang Space Launch Center in south China's Hainan Province, successfully completed automated docking with the orbiting Tiangong-2 space lab at 12:23 p.m. Saturday, according to Beijing Aerospace Control Center. It is the first docking between the spacecraft and space lab. (Xinhua/Yu Tao)

The rendezvous and docking process of the Tianzhou-1 began even when it was dozens of kilometers away from the Tiangong-2 space lab. But even from that distance, they are able to read each other’s relative positions and velocity.

The next phase of the automatic approach and docking operations began when the two vehicles were just 5 kilometers apart. Then the Tianzhou-1 moved towards the remaining three parking points, at 400, 120, and 30 meters.

At each of these parking points, the relative position of Tianzhou-1 was assessed by ground controllers before a command was given.

Photo taken on April 22, 2017 shows the Tianzhou-1 cargo spacecraft docking with the orbiting Tiangong-2 space lab on a screen at Beijing Aerospace Control Center in Beijing, capital of China. The Tianzhou-1 cargo spacecraft, China's first cargo spacecraft, which was launched Thursday evening from Wenchang Space Launch Center in south China's Hainan Province, successfully completed automated docking with the orbiting Tiangong-2 space lab at 12:23 p.m. Saturday, according to Beijing Aerospace Control Center. It is the first docking between the spacecraft and space lab. (Xinhua/Wang Sijiang)