China’s Human Spaceflight Entered the Era of Space Station
At about 8:15 am on April 2, Tiangong 1, China’s first target spacecraft, returned from the outer space and fell in the central region of the South Pacific, formally finishing and ending its seven-year journey in space.
As China’s “first home” in the vast universe, Tiangong 1 were launched on September 29, 2011 with two-year original design life. In the following years, it conducted 6 times of rendezvous and docking successively with Shenzhou 8, Shenzhou 9 and Shenzhou 10 spacecrafts and completed various established tasks, making significant contributions to the development of China’s manned spaceflight. On March 16, 2016, Tiangong 1 officially terminated its data service and entered its orbital decay period.
Tiangong 2 were launched on September 15, 2016 and successfully replaced Tiangong 1 series to complete more tasks. Tiangong 2 are part of the second phase of the second step of the “three-step” strategy of Chinese manned spaceflight project.
Unlike Tiangong 1, which were mainly used to verify the rendezvous and docking technology, Tiangong 2 are particularly much more focused on science and tasks that embody Chinese scientific frontier and strategic high-tech development directions. Tiangong 2 space laboratory possessed a variety of instruments and devices, including comprehensive material experimental device, concomitant satellites of Tiangong 2, the “Bai Bian Jin Gang” liquid bridge, the “Tianji” telescope and the mini greenhouse. 14 space science and application projects were planned to be carried out by Tiangong 2 such as space astronomy exploration, space environment monitoring and space materials science. The “Ultra-high-precision space cold atomic clock” carried by Tiangong 2 was not only the first “space cold atomic clock” being put in orbit to carry out scientific experiments in the world, but also the most accurate and precise atomic clock currently operating in space. The error of the atomic clock would not exceed 1 second in 30 million years. The space cold atomic clock, together with gamma-ray polarization detection and open space quantum key distribution experiment, formed the three key application and experiment projects of Tiangong 2.
Currently, the third step of China’s manned spaceflight project has been fully started. “Before or after June of next year, China will implement the first flight mission of Long March 5B carrier rocket. Afterwards, it will successively launch the core module and experimental module to carry out space station assembly in orbit”, introduced by Yang Liwei, the first person sent into space by the Chinese space program and the deputy office director of the manned spaceflight project.
Both Tiangong 1 and Tiangong 2 are just steps of China building space stations. Tiangong Space Station of China has designed a complete renewable life support system and a reliable power system, which are expected to be fully completed by 2022. Once Tiangong Space Station is put into operation, it will become the “home of space” for astronauts and will be the “space laboratory” for scientific research.