What is the Tiangong space station?

Tiangong (Chinese: 天宫, "Heavenly Palace") is China's permanent crewed space station in low Earth orbit at ~400 km altitude, inclined 41.5°. It consists of a core module (Tianhe, launched April 2021) and two laboratory modules (Wentian and Mengtian, both 2022). It is designed to support a rotating crew of three, with occasional six-person overlapping crews during handovers. China operates it independently — Chinese taikonauts are barred from the International Space Station under US law. CNSA's official Tiangong page provides mission updates.

How does Tiangong compare to the ISS?

The ISS has a mass of about 420 tonnes and a habitable volume of ~930 m³ — roughly the interior of a Boeing 747. Tiangong in its core T-shape weighs around 70 tonnes with ~110 m³ of habitable volume. China is planning expansion modules that will bring the station closer to the ISS in capability. The ISS is scheduled for deorbit no earlier than 2030; Tiangong is intended to remain operational through at least 2035. Both stations occupy similar orbital altitudes and conduct microgravity research, Earth observation, and technology demonstration.

Who has visited Tiangong?

Tiangong is crewed by taikonauts (Chinese astronauts) on six-month rotations, delivered by Shenzhou spacecraft on Long March 2F rockets from Jiuquan. Shenzhou-15 through Shenzhou-20 have all carried three-person crews. Starting in 2026, China has announced plans to host international guest cosmonauts through bilateral agreements with ESA and other agencies, though specifics of timing remain subject to negotiation. The ESA overview of China's space station summarises international cooperation status.

What science is conducted on Tiangong?

Tiangong carries dozens of experiments across life sciences (cell biology, plant growth), materials science (semiconductor crystal growth in microgravity), fluid physics, and fundamental physics. The Mengtian module houses a space application system centred on microgravity research. Externally mounted instruments monitor Earth's surface and atmosphere. The station also hosts the Chinese Space Station Telescope (CSST) — a 2-metre optical survey telescope scheduled for launch that will operate in a similar orbit to Tiangong and dock for servicing. Nature's overview of CSST describes its science goals.

China Expands Tiangong Space Station — New Module Docked

Tiangong's expansion programme

The core Tiangong configuration — Tianhe + Wentian + Mengtian — was completed in November 2022, forming a T-shape with a total mass of around 70 tonnes. China's space agency CNSA has announced plans for additional modules, including an expanded docking hub and a dedicated life-science research module, that would bring the station's mass to approximately 180 tonnes and its habitable volume to over 400 m³ by the late 2020s.

Each expansion module is delivered by the Long March 5B rocket — China's largest — and autonomously docks with the station using the SADA (Space Station Application Docking Adapter) system. The approach mirrors the ISS incremental build strategy but on a faster timeline: the core Tiangong assembly took just 18 months.

The Chinese Space Station Telescope

The most scientifically significant planned addition to Tiangong's programme is the Chinese Space Station Telescope (CSST), also known as the Xuntian ("Survey the Sky") telescope. With a 2-metre primary mirror and a field of view 350 times larger than Hubble's, it will conduct a wide-field optical survey of 17,500 square degrees of sky over 10 years. CSST will orbit within proximity of Tiangong for periodic servicing by taikonauts — an architecture similar to the Hubble servicing missions.

CSST's science goals include weak gravitational lensing surveys of dark matter, and mapping large-scale structure to constrain dark energy — objectives that complement ESA's Euclid mission. Our article on the Euclid dark universe map covers what wide-field space surveys can reveal about the universe's structure.

China expands Tiangong

Tiangong's expansion programme

The Chinese Space Station Telescope

Frequently asked questions