Development and Construction Progress of the Tiangong Space Station in China

China's Tiangong space station is the world's third on-orbit assembly multi-module space station. It has appropriate scale and function conforming to China's national conditions and prominent Chinese elements. After completion, it will become China's space home and national space laboratory. This paper first introduces the overall scheme and key technologies of the Tiangong space station. The Tiangong space station comprises three modules: The Tianhe core module and the Wentian and Mengtian experimental modules, which are in a T-shaped configuration. The Tianhe core module is in the middle, and the Wentian and Mengtian experimental modules are connected on both sides. The Tiangong space station is equipped with forward, backward, and radial interfaces. The forward interface is mainly used for docking manned spacecraft and the Xuntian space telescope, the backward interface is mainly used for docking cargo spacecraft, and the radial interface is mainly used for docking manned spacecraft. On the basis of the technology in the early stage of China's manned spaceflight project, the Tiangong space station has made breakthroughs in key technologies, such as space robot arms, high-efficiency power supply systems, physicochemical regeneration life-support systems, and on-orbit propellant supplement systems. The Tiangong space station is China's first large complex spacecraft launched separately and assembled in orbit. Its development process has the characteristics of overall planning and multi-line development. The assembly, integration, and testing of the three modules of the Tiangong space station are mainly conducted in the super large spacecraft AIT center of the China Academy of Space Technology in Tianjin. The main test projects conducted while developing the Tiangong space station mainly include mechanical testing, thermal testing, three-module joint testing, and module transposition testing. Through these test projects, the Tiangong space station design has been comprehensively verified, laying a solid foundation for the on-orbit assembly and construction of the Tiangong space station. On April 29, 2021, the Tianhe core module was successfully launched into orbit from the Wenchang space launch center in Hainan, and the task of constructing China's Tiangong space station officially started. After the Tianhe core module was launched into orbit, a 1-year in-orbit key technology verification flight was conducted to verify the key technologies of the space station construction. After the verification, it was officially transferred to the assembly and construction stage to complete the in-orbit construction of the Tiangong space station with three modules. Once constructed, the Tiangong space station will operate in orbit for more than ten years. During this period, various scientific experiments and technical tests will be continuously conducted using the experiment support facilities inside and outside the cabin. During the operation of the Tiangong space station, the Xuntian space telescope will be launched to fly in common orbit with the space station, and the space telescope will be provided with on-orbit services such as propellant replenishment, maintenance, and repair through the space station. In the future, more spacecraft may fly in common orbit with the Tiangong space station to receive on-orbit services. The current T-shaped three-module assembly configuration of the Tiangong space station has a good capacity for module expansion and application support expansion. It has the expansion capacity of docking three new modules to form a six-module assembly of approximately 180 tons.