China Plans Six-Module Tiangong Expansion Ahead of ISS Retirement

China will attach a multifunctional module to Tiangong’s Tianhe core, turning the current T-shaped station into a cross layout. Two additional laboratory modules will follow, creating a six-module complex with an estimated mass of about 180 tonnes (?198 tons). The new module will provide several docking ports and a dedicated airlock for extravehicular activities.

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The International Space Station, a 15-nation partnership led by NASA, is slated for controlled deorbit in early 2031 using a SpaceX-built vehicle. Its retirement will leave low-Earth-orbit research capacity largely to Tiangong, which is designed for a 15-year service life.

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CCTV announced the expansion plan, while the China Academy of Space Technology is upgrading Tiangong’s robotic arms and preparing the Long March 5B launch vehicle with an enlarged payload fairing. Beijing’s space agency markets the station as a “global laboratory” open to international crews.

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Since its 2022 launch, Tiangong has hosted over two dozen astronauts and conducted more than 260 experiments. The six-module target would raise the station’s mass to roughly 180 tonnes and expand docking capacity with multiple ports.

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The expansion addresses rising demand for orbital science and positions China as the primary provider of a long-term low-Earth-orbit laboratory after the ISS exits. Larger mass and added modules enable more complex experiments and longer crewed missions, attracting partners lacking independent stations. Tiangong also set a 9-hour-6-minute EVA record, surpassing NASA’s longest.

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CCTV reported that the new module will feature multiple docking ports, including interfaces for two future laboratory units, paving the way for the six-module layout. NASA confirmed plans to retire the ISS in early 2031 and is developing a dedicated deorbit vehicle with SpaceX. Beijing emphasized openness, noting upcoming astronaut participation from Pakistan, Hong Kong and Macau.

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U.S. law currently bars NASA from cooperating with China on space projects, limiting joint scientific use of Tiangong and raising concerns among U.S. officials about reduced international collaboration in low-Earth-orbit research.

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Sources differ on the ISS deorbit timeline, citing 2030 in one report and early 2031 in another. China has not released a specific schedule for the Tiangong module launches, leaving the exact timing of the six-module configuration uncertain.

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The upgraded Long March 5B rocket will deliver the multifunctional module within the next few years, followed by the two laboratory segments. Successful assembly would cement Tiangong as the sole operational LEO station after the ISS’s deorbit.

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