At 1455 on June 19, the second docking exercise of Tianzhou-1 cargo spacecraft and Tiangong-2 space station was successfully completed.
Tianzhou-1 was first tested at 0937 on the same day for orbital flight under the guidance of ground control. The ground control first sent separation instructions: for Tiangong-2 to halt, unlocking of both docking mechanisms, and separation of both spacecraft.
According to reports, Tianzhou-1 gradually retreated to about 5 km and stopped for 90 minutes according to the procedure. Once ground control had established that the spacecraft was stable, it was then instructed to begin its flight. The spacecraft flew a distance of 5 km to and fro around Tiangong-2. Tianzhou-1 completed the backwards flight and a 180 degree maneuver around Tiangong-2, whereas the latter also made a 180 degrees, but forward yaw maneuver.
After the completion of the flight test, both Tianzhou-1 and Tiangong-2 began their second rendezvous test. Tianzhou-1 departed 5km away from the berth, and gradually flew closer to Tiangong-2. It eventually closed the gap until they were 30 meters apart before the docking procedure with Tiangong-2 began, therefore completing the exercise.
The successful completion of this test is a testament to the successful culmination of various technologies of multi-directional spacecraft docking, and bears significant portents for the future of space station projects.