Overview
The Chinese Space Station (CSS), known as Tiangong (天宫, "Heavenly Palace"), is a modular space station in low Earth orbit operated by the China Manned Space Agency (CMSA). The station was assembled between April 2021 and November 2022 across three Long March 5B launches, reaching its baseline T-shaped configuration with three pressurised modules. Tiangong orbits at approximately 390 km altitude with an inclination of 41.5° and has been permanently crewed since June 2022.
Core Modules
| Module | Chinese Name | Launch | Mass | Role |
|---|---|---|---|---|
| Tianhe | 天和 (Harmony of Heavens) | 29 Apr 2021 | ~22,600 kg | Core module — crew quarters (3 berths), life support, propulsion, attitude control and station management. Contains the main docking hub with five ports. |
| Wentian | 问天 (Quest for Heavens) | 24 Jul 2022 | ~23,000 kg | Laboratory cabin I — life sciences, biotechnology and ecological experiments. Includes a backup crew sleep station, a secondary airlock, a small robotic arm and an external experiment platform. |
| Mengtian | 梦天 (Dreaming of Heavens) | 31 Oct 2022 | ~23,000 kg | Laboratory cabin II — microgravity physics, fluid science, materials science and combustion experiments. Features a cargo airlock for transferring payloads to the external exposure platform. |
Tianhe — Core Module
Tianhe is the command-and-control centre of the station. At 16.6 m long and 4.2 m in diameter, it is divided into three sections: a living area with crew quarters, a working area with experiment racks, and a resource compartment housing propulsion and life support systems. The forward end features a docking hub with one forward and two radial berthing ports (used by Wentian and Mengtian). The aft end has a docking port for Tianzhou cargo spacecraft and Shenzhou crew vehicles.
Tianhe provides the station's primary environmental control and life support system (ECLSS), including oxygen generation via electrolysis, CO₂ removal and water recovery. Four solar arrays on the resource section — later supplemented by arrays on the lab modules — provide electrical power.
Wentian — Laboratory Cabin I
Wentian is the station's first science laboratory module, launched on a Long March 5B in July 2022. At approximately 17.9 m long, it is one of the longest single-module space station elements ever launched. Wentian carries 8 experiment racks focused on life sciences and serves as a backup control centre for the station.
The module includes a second airlock with a wider hatch than Tianhe's, making it the primary EVA exit point. Wentian also carries a 5-metre-long small robotic arm that can operate independently or be attached to the station's larger 10-metre main arm for extended reach. An external exposed experiment platform allows payloads to be operated in the vacuum of space.
Mengtian — Laboratory Cabin II
Mengtian is the station's second laboratory and final baseline module, launched in October 2022. It carries 13 experiment racks dedicated to microgravity research — including a cold atom clock expected to be among the most precise timekeeping instruments in space. The module also contains a cargo airlock that can transfer payloads and experiments between the pressurised interior and an external exposure platform without requiring a crewed EVA.
Supporting Vehicles
Shenzhou: China's crewed spacecraft carries up to 3 taikonauts to and from Tiangong, launching atop a Long March 2F from the Jiuquan Satellite Launch Center. Crew rotations occur approximately every six months.
Tianzhou: Uncrewed cargo spacecraft that delivers supplies, propellant and experiments. Tianzhou vehicles also provide orbital reboost capability and are used to remove waste from the station upon departure.
Xuntian Space Telescope
China's next major addition to the Tiangong programme is the Xuntian (巡天) Space Telescope — a Hubble-class optical observatory with a 2-metre primary mirror and a field of view 300 times larger than Hubble's. Xuntian is designed to co-orbit with Tiangong and periodically dock with the station for servicing, instrument upgrades and refuelling. It is expected to launch in the 2026–2027 timeframe.
Future Expansion
CMSA has announced plans to expand Tiangong from its current three-module T-shape to a six-module cross or cruciform configuration. Additional modules may include a second core module, further laboratory space and enhanced habitation capacity. The expanded station could support crews of up to 6 taikonauts and serve as a platform for lunar mission staging and deep-space technology demonstrations.