The Tiangong space station (), officially in English the China Space Station (CSS; ), is China's first permanently crewed space station, in low Earth orbit since 2021. Operated by the China Manned Space Agency (CMSA), it is China's third space station, under the Tiangong subprogram of the China Manned Space Program. A space laboratory, it hosts experiments on bioastronautics, microgravity, materials science and space technology. Crews of three travel aboard the Shenzhou spacecraft for missions of about six months, with temporary crew sizes of six during handovers. Cargo missions use the Tianzhou spacecraft. It is one of two operational space stations, alongside the International Space Station (ISS).
When China formally requested to join the ISS program in 2007, Roscosmos and the European Space Agency (ESA) supported cooperation with China, but the Wolf Amendment, enacted by the United States since 2011, prohibited Chinese participation. That same year, China launched Tiangong-1, gaining rendezvous and docking experience. In 2016, Tiangong-2 developed longer-term life support systems, and autonomous docking and refueling via Tianzhou. The current station has supported experiments involving researchers from 17 countries; Chinese experiments include atomic clocks, Bose–Einstein condensates, and the agricultural cycle of rice. It hosted the first astronaut from Hong Kong, and China is training astronauts from Macau and Pakistan.
Tiangong is the third modular space station, after Mir and the ISS. Its core module, Tianhe, was launched in April 2021 and was followed by the Wentian and Mengtian experiment modules in July and October 2022; The modules were assembled at and launched from Wenchang Space Launch Site, atop Long March 5B rockets. The station has three robotic arms in use and three external Chinese Docking Mechanism ports. Xuntian, a space telescope scheduled for launch in 2027, is designed to periodically dock with the station for servicing and refueling. Orbiting at an altitude of and inclination of 41°, it has a pressurised volume of , slightly over one third that of the ISS.
Shenzhou 12 in June 2021 was the first crewed mission to the station. Shenzhou 15 in November 2022 completed major station assembly and began continuous occupation; later missions have focused on scientific research. Shenzhou 23 is the first attempt at a year-long mission. Tiangong is the first crewed spacecraft to use ion thrusters, for orbital station-keeping, while communications are relayed through the Tianlian satellite network. , 21 spacecraft have docked to the station: 12 Shenzhou and 9 Tianzhou. Crews have made 24 spacewalks, using the Feitian suit, including the longest spacewalk ever, exceeding 9 hours in 2024.
Nomenclature Early names used in the Chinese space program were largely drawn from the revolutionary history of the People's Republic of China. In recent decades, these have been replaced by names with mythological or religious connotations. Examples include the Shenzhou () crewed spacecraft, the Shenlong () spaceplane, the Shenguang () high-power laser, and the Shenwei () supercomputer.
These mythological names continue in the Chinese Lunar Exploration Program, whose probes are named Chang'e after the Moon goddess. The name Tiangong was similarly reported to evoke cultural and romantic imagery, with the launch of Tiangong-1 inspiring public expressions such as love poetry, and media comparing the docking of spacecraft to the reunion of the cowherd and the weaver girl from folklore.
In 2011, Wang Wenbao, director of CMSA, stated that the agency sought names that would "carry a resounding and encouraging" message and reflect public participation in the program.
On 31 October 2013, CMSA announced standardized names for space station elements: Tiangong would refer to both the precursor space labs—Tiangong-1 (2011) and Tiangong-2 (2016)—and the modular space station. Tianzhou () for the cargo spacecraft Tianhe () for the core module of the modular space station, launched on 29 April 2021. Wentian () for the first laboratory module of the modular space station, launched on 24 July 2022. Mengtian () for the second laboratory module of the modular space station, launched on 31 October 2022. Xuntian () for the co-orbiting space telescope module, scheduled for launch in 2027.
Purpose and mission
According to CMSA, which operates the space station, the purpose and mission of Tiangong is to develop and gain experience in spacecraft rendezvous technology, permanent human operations in orbit, long-term autonomous spaceflight of the space station, regenerative life support technology and autonomous cargo and fuel supply technology. It will also serve the platform for the next-generation orbit transportation vehicles, scientific and practical applications at large-scale in orbit, and technology for future deep space exploration.
CMSA also encourages commercial activities led by the private sector and hopes their involvement could bring cost-effective aerospace innovations. Space tourism aboard the station is also being considered.
China launched Tiangong-1 in 2011, gaining rendezvous and docking experience. In 2016, Tiangong-2 developed longer-term life support systems, and autonomous docking and refuelling via Tianzhou.
Scientific research
The space station will have 23 experimental racks in an enclosed, pressurised environment. There will also be platforms for exposed experiments; 22 and 30 on the Wentian and Mengtian laboratory modules, respectively. Over 1,000 experiments are tentatively approved by CMSA, and scheduled to be conducted on the space station.
The programmed experiment equipment racks for the three modules as of June 2016 were: Space life sciences and biotechnology Ecology Science Experiment Rack (ESER) Biotechnology Experiment Rack (BER) Science Glove-box and Refrigerator Rack (SGRR) Microgravity fluid physics and combustion Fluids Physics Experiment Rack (FPER) Two-phase System Experiment Rack (TSER) Combustion Experiment Rack (CER) Material science in space Material Furnace Experiment Rack (MFER) Container-less Material Experiment Rack (CMER) Fundamental Physics in Microgravity Cold Atom Experiment Rack (CAER) High-precision Time-Frequency Rack (HTFR) Multipurpose Facilities High Micro-gravity Level Rack (HMGR) Varying-Gravity Experiment Rack (VGER) Modularized Experiment Rack (RACK)
Biology Agriculture in microgravity was explored with cultivation of rice and Arabidopsis thaliana as sustainable food sources for long-term spaceflight. In 2022, the station completed the first complete agricultural cycle of rice in microgravity, from seed to harvest to seed replanting.
A novel bacterial strain, Niallia tiangongensis, was discovered on the station in May 2023 during Shenzhou 15. The strain is particularly adept at metabolizing gelatin.
Physics Physics experiments are contained in the Mengtian module.
The Cold Atom Physics Research Rack (CAPR) brings ultracold atoms down to a temperature of 100 picokelvin, via a rubidium-87 Bose–Einstein condensate and a method scientists call "Two-Stage Crossed Beam Cooling".
The High-precision Time-Frequency Rack (HTFR) contains three types of atomic clock: a strontium-based optical clock, a hydrogen maser, and a laser-cooled microwave clock, achieving a time deviation of 0.08 picoseconds per 300 seconds.
Education and cultural outreach The space station features space lectures and popular science experiments to educate, motivate and inspire the younger Chinese generation and world audience in science and technology. Each lecture is concluded with a question-and-answer session with school children's questions from classrooms across China. The first and second Tiangong space lesson was conducted in December 2021 and March 2022, as a part of the Shenzhou 13 mission. This tradition continued with the Shenzhou 14.
The CSSARC is the Amateur Radio payload for the Chinese Space Station, proposed by the Chinese Radio Amateurs Club (CRAC), Aerospace System Engineering Research Institute of Shanghai (ASES) and Harbin Institute of Technology (HIT). The payload will provide resources for radio amateurs worldwide to contact onboard astronauts or communicate with each other, aim to inspire students to take interests and careers in science, technology, engineering, and math, and encourage more people to get interested in amateur radio.
The first phase of the payload is capable of providing the following functions utilising the VHF/UHF amateur radio band:
V/V or U/U crew voice V/U or U/V FM repeater V/V or U/U 1k2 AFSK digipeater V/V or U/U SSTV or digital image
Structure Tiangong is a third-generation modular space station. First-generation stations, such as the early Salyut and Almaz stations and Skylab, were single-module outposts that were not designed for resupply. Second-generation stations, including Salyut 6 and 7 and Tiangong 1 and 2, incorporated docking ports that enabled mid-mission resupply. Third-generation stations, such as Mir and the International Space Station, are modular complexes assembled in orbit from multiple components launched separately. Modular design can improve reliability, reduce costs, shorten development cycles, and support more diverse mission requirements.
Below is a diagram of major station components.
Key to box background colors: Pressurised component, accessible by the crew without using spacesuits Docking/berthing port, pressurized when a visiting spacecraft is present Airlock, to move people or material between pressurized and unpressurized environment Unpressurised component
Modules
Tiangong was completed in a three-module configuration in 2022. China has proposed several expansion concepts. Initial proposals called for enlarging the station to six modules by duplicating the original trio, but by 2023 this evolved into a plan to add a fourth module with six docking ports to accommodate future growth. In October 2023, China announced a revised roadmap to expand Tiangong to six modules beginning in 2027.
The Tianhe core module provides life support and living quarters for three crew members and houses the station's guidance, navigation, and orientation control systems. It also contains the main power, propulsion, and environmental control systems. It is based on the Russian Functional Cargo Block. Tianhe is divided into three sections: living quarters, a service module, and a docking hub. The living area includes a kitchen, toilet, fire suppression equipment, atmospheric control systems, computers, scientific apparatus, and communications equipment for contact with ground control in Beijing. Tianhe also carries the Core Module Manipulator (CMM), a large robotic arm used for EVA support and as a backup for module relocation. A full-scale mockup of Tianhe was displayed at the China International Aviation & Aerospace Exhibition in Zhuhai in 2018. CMSA videos have shown that two core modules have been constructed.
The first of the two Experiment Modules, Wentian, provides additional avionics, propulsion, and life-support capacity as backups to Tianhe. It includes three short-term crew quarters for use during handovers and features a dedicated airlock for extravehicular activities (EVAs), replacing the temporary use of Tianhe's docking hub, which was not purpose-built for that function. Wentian carries internal experiment racks and 22 external experiment adapters. It was launched and docked with Tianhe on 24 July 2022 and moved to its permanent starboard position on 30 September.