Chinanews, Jiuquan, October 16th, title: "Tianjin" radial rendezvous and docking perfect debut "Space Waltz" and then display new skills

　　Author Ma Shuaisha Guo Chaokai

　　At 6:56 on October 16, the Shenzhou 13 manned spacecraft completed a fully autonomous radial rendezvous and docking with the Tianhe core module about 6.5 hours after its orbit. Rendezvous and docking, that is, rendezvous and docking with the space station through the interface under the sky and core cabin.

　　The combination of the Tianhe core module and the Shenzhou spacecraft completed the perfect debut of the radial rendezvous and docking. Although the direction has only changed 90 degrees, the docking is much more difficult than the Shenzhou 12 mission.

　　In order to ensure that the first radial rendezvous and docking mission is foolproof, the R&D team of the 502nd Institute of the China Aerospace Science and Technology Group has conducted several years of technical research and a large number of ground experiments on the radial rendezvous, and carried out the cooperation with the Shenzhou 12 manned spacecraft before returning to the earth. The space station's orbiting and radial rendezvous tests have verified the key technologies for the official implementation of the radial rendezvous on Shenzhou 13.

　　There are "three difficulties" in radial rendezvous and docking, which also makes this "space waltz" even more exciting.

　　First, it is "difficult" to continuously control the attitude and orbit.

For forward and backward rendezvous and docking, the 200-meter holding point is a stable holding point. Even if the engine is not working, the spacecraft can maintain a stable attitude and orbit for a long time.

However, the radial rendezvous does not have a stable halfway point. It is necessary to continuously control the attitude and trajectory of the spacecraft, which consumes a lot of propellant and makes troubleshooting difficult.

　　The second is the "difficulty" in determining the attitude and relative position.

The Shenzhou manned spacecraft is equipped with sensors, which are like the eyes of the spacecraft. It determines its flight attitude and the relative position of the space station by observing the stars and preset landmarks.

However, during the radial rendezvous process, the spacecraft needs to maneuver from a horizontal flight to a vertical flight and other large-scale postures, so higher requirements are put forward for the "eyes" to see the target and to ensure that the "eyes" will not be disturbed by complex illumination changes. .

　　The third is that the astronauts’ manual rendezvous mode is “difficult”.

In the process of radial rendezvous and docking, the most familiar reference datum, the earth, is basically lost, the measurement and control conditions have become worse, and the relative dynamic motion characteristics are different from forward rendezvous, which makes the operation of astronauts in manual rendezvous mode more difficult.

　　The entire process of this radial rendezvous and docking is completed intelligently and autonomously by the spacecraft under the command of the guidance, navigation and control (GNC) system.

Radial rendezvous and forward rendezvous are both normal rendezvous methods for manned spacecraft of the Chinese space station, and will be used alternately in future manned rendezvous and docking missions of the space station.

The complete success of this first show will lay a solid foundation for the construction and operation of the subsequent space station.

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