Recently, it was learned from the Sixth Academy of China Aerospace Science and Technology Corporation that, with the cooperation of heaven and earth, the air bottle of the electric propulsion system of Tiangong space station was installed in orbit. The 801 Institute of the Academy completed the supplement of xenon, the propellant of the electric propulsion system, for the first time by means of "air exchange" rather than "air supplement". The working principle of an electric propulsion system is to first convert inert gases such as xenon into charged ions, and then accelerate and eject these ions to generate propulsion force, thereby completing tasks such as spacecraft attitude control, orbit correction, and orbit maintenance. The use of the electric propulsion system on the Tiangong space station is the first show in the field of Human spaceflight. The electric propulsion system of the space station with atmospheric bottles as "external components" will greatly extend its service life and play an important role in the long-term safe and stable flight of the space station. It is reported that in order to provide air exchange for the electric propulsion system in orbit, the research and development team creatively proposed a simplified floating docking form: the initial positioning of the robotic arm is achieved through a coarse positioning guide device, and further correction is made through autonomous precise positioning. This method greatly improves the reliability of docking, ensuring accuracy even after multiple disassembly and assembly in orbit. Meanwhile, as gas cylinders are installed at a unified interface, in principle, as long as they meet the interface requirements, the space station electric propulsion system can install gas cylinders with different volumes, working pressures, and filling gases. The versatile nature of the gas storage module not only greatly increases the lifespan and reliability of the electric propulsion system, but also enriches its functionality. Considering the many uncontrollable factors in the space environment, in addition to supporting the robotic arm to automatically replace gas cylinders in orbit, the research and development team also designed a plan for astronauts to manually replace gas cylinders. (New News Agency)