Tiangong: China’s Station Built Around Five Research Themes

China's Tiangong space station, the Heavenly Palace, has been in orbit since 2021 and is one of exactly two space stations circling Earth, alongside the International Space Station. Its experiments are organised around five research themes, which the video reads as pointing toward large-scale construction and self-sufficiency in space.

From Tiangong 1 to Tiangong 3

China's station efforts began in 2011 with the launch of the first Tiangong, launched whole in one go. It was a simple tube-like prototype with a sleeping and living area, a habitable lab for docking and orbital experiments, and a propulsion module. It was 10.4 m long, compared with the ISS at 108 m. It was meant to master rendezvous and docking, and it stayed in space a little under seven years. China sent both crewed and uncrewed missions to it.

A second station, Tiangong 2, launched in 2016 to field test technologies for a larger station. It was de-orbited in 2019 once its tasks were complete.

The current station

Tiangong, often called Tiangong 3, consists of the Tianhe core module, where the crew live, and two science modules, Wentian and Mengtian. Wentian is designed to study space's impact on living things and to develop medical technologies; Mengtian focuses on microgravity effects on fluid behaviour, combustion and more. The station weighs 100 tons, is 55 m long and can house up to six taikonauts. It was assembled module by module, with modules launched between 2021 and 2022. An external robotic arm can carry a taikonaut to various parts of the station for spacewalks.

Life aboard resembles the ISS: 120 kinds of space food, daily exercise against muscle atrophy, and school collaborations, including a demonstration of fire without gravity and rice seeds grown from the same batch as seeds on the station.

Five research themes

The themes over the station's 15-year lifespan are on-orbit assembly and construction, robotics and autonomous systems, new energy and propulsion, environmental control and life support, and new generic spacecraft technology.

On construction, a 2023 paper by Chinese scientists set a goal of 3D printing and other manufacturing in orbit. In 2018 they pioneered 3D printing of ceramics in microgravity. The paper also describes inflatable structures that could serve as habitats on neighbouring bodies. Taikonauts have tested robots in microgravity, including one run through a pipe.

On energy, the video notes that at Jupiter's distance light drops to 3% of Earth's level, and infers China is considering large projects at such distances. Early this year, taikonauts carried out what the video calls the first experiment of its kind using a semiconductor catalyst, producing oxygen and ethylene from carbon dioxide in artificial photosynthesis. Ethylene can be used to make rocket fuel, and researchers believe the process could also yield methane, formic acid or sugars. On the ISS, oxygen recycling by electrolysis is thought to take a third of the station's energy use; the new process is described as more efficient and works at room temperature.

Collaboration

Under American law, American astronauts may not board Tiangong without express permission from Congress. Europe initially planned to collaborate but pulled out in 2023, citing insufficient budget and no political green light. China has invited scientists worldwide to perform joint experiments.