At 9:32，November 3, 2022, the Mengtian lab module of the space station successfully completed its transposition. During the transposition, the Mengtian lab module first completed the relevant state setting, then separated from the space station assembly, subsequently completed the transposition through plane transposition for about an hour, and then docked with the lateral port of the node module of the Tianhe Core Module again. This afternoon, the crew of Shenzhou XIV will enter the Mengtian lab module. The completion of the transposition for the Mengtian lab module marks the completion of the on-orbit assembly of the "T" basic configuration of the Chinese space station and a key step towards the goal of building the space station. As planned, test and evaluation of the space station assembly’s basic function will be carried out subsequently.

The product realizing this transposition function is the transposition mechanism developed by Shanghai Academy of Spaceflight Technology. The Chinese space station will once again perform the perfect "turn-around in space", presenting a "graceful dance" in the starry sky.

Accurate alignment: the cone rod type mechanism makes the capture and docking freer.

The first step of transposition is to dock, that is, connect the Mengtian lab module with the Tianhe core module through the transposition mechanism. The transposition mechanism on the Mengtian lab module adopts a cone rod docking mode. The team has configured a capture rod at the front section of the rotary arm of the transposition mechanism, which is wrapped in the "petals" formed by three guide pieces, just like the "stamens". When the capture mechanism is close to the base, the six guide pieces of the two products will be initially positioned. Subsequently, the cone rod like the "flower stamens" is pushed out by the drive assembly. With the cooperation of the tension spring assembly, it can swing within a certain range, ensuring the adaptability of connection and locking with the base. Such structural design can enable the transposition mechanism to have perfect capture and docking capabilities.

Flexible movement: "coupling hardness with softness" makes the turning arm stable and reliable.

To transfer the Mengtian lab module from the Tianhe core module to the side interface is not as easy as we "turn our body around". So, how to make the 150kg rotating arm smoothly drive the 23 ton Mengtian lab module to achieve the "turning"? Two driving parts - joint driving mechanism - are installed on the rotary arm of the Mengtian lab module, just like the two "motion joints" of our arm. Near the end of the Mengtian lab module is the "shoulder joint", and the other is the "wrist joint" connected with the capture mechanism. When the two "joints" work, they must achieve smooth transition from acceleration to uniform speed, so as to ensure stability in the moving process.

Stable rotation: to achieve large rotation in a small space.

In order to enable the Mengtian lab module to have the rotation ability under large inertia load, cabin body stop control mode is adopted in this transposition process, that is, during the transposition, the "shoulder joint" is used for one start-stop, and the "wrist joint" is used for two start-stops, so as to achieve a smooth turning.

At this moment, the "dancers" in space are making a perfect "turn-around in space". They will perform a different "youth dance" in the vast starry sky, so that every audience can stand and look up to their "graceful dance".