Pang Zhihao, Chief Science Communication Expert in National Space Exploration Technology.

Since the construction of China's space station was completed in orbit by the end of 2022, it has become a national space laboratory and the largest long-term human-maintained space experiment platform in the history of chinese aerospace. With the crew of the Shenzhou 19 spacecraft entering space, the fourth manned space mission in the application and development phase of China's space station has officially begun.

What technical features does China's space station have? What role will it play in the future? The following will provide detailed answers.

A photo of the Chinese space station taken by the Shenzhou 16 crew.

1 Overall Overview

In order to make our country one of the few in the world that can independently master long-term manned flight technology in near-Earth space, with the capability to carry out long-term scientific and technological experiments and comprehensive development of space resources with human participation, on September 25, 2010, the state approved the construction of China's first near-Earth orbital manned space station, composed of 13 systems. After 12 years of effort, our country finally achieved this goal by the end of 2022.

The construction of our first space station did not follow the old path of the usa and the soviet union, which first built single-module stations and then multi-module stations. Instead, it directly built a multi-module space station that reaches the standard of the world's third-generation space stations or above, and has also achieved full localization of products and raw materials, with key core components being 100% independently controllable.

This space technology building is based on the configuration of the "Tianhe" core module, "Wentian" experimental module, and "Mengtian" experimental module, which are docked together. Each module has a mass of about 20 tons and, after sequential launches, they formed a horizontally symmetrical T-shaped configuration in orbit through docking and repositioning, with the "Tianhe" core module centered, and the "Wentian" and "Mengtian" modules docked on either side.

The Chinese space station has distinct Chinese characteristics and modern features, utilizing a combination of repositioning mechanisms and robotic arms for cabin segment transfers and dockings. With the cooperation of astronauts and robotic arms, complex extravehicular construction and operational activities can be accomplished.

To complete the construction of the space station, China launched the "Tianhe" core module, two "Tianzhou" cargo spacecraft, and two "Shenzhou" manned spacecraft in 2021, conducting a year-long verification of key technologies. Subsequently, in 2022, China began the on-orbit construction phase of the space station, launching the "Wentian" and "Mengtian" experimental modules, as well as two each of the "Tianzhou" cargo spacecraft and "Shenzhou" manned spacecraft, increasing the astronauts' operational space to 110 cubic meters.

With the completion of the on-orbit construction phase of the space station, China’s space station entered the application and development stage starting in 2023. Astronauts rotate crews continuously and maintain the space station, conducting space science research, technological experiments, and other space station applications for at least the next ten years.

The Shenzhou 19 spaceflight mission is the fourth manned flight mission as the Chinese space station enters the application and development phase. They are rotating in orbit with the Shenzhou 18 crew and will remain in orbit for approximately six months.

Currently, the Chinese space station can accommodate three people long-term, with a crew change every six months. During the 6 to 10 days of astronaut rotation, there can be a maximum of six people in the space station. Each astronaut crew is led by one commander who has been to space, with the remaining personnel composed according to mission needs, consisting of space pilots, aerospace flight engineers, and payload specialists.

Overall, the Chinese space station is neither excessively large nor overly complex, but maintains a moderate scale, making it an economical and practical model. Its features include a high starting point, high benefits, new technology, and strong support. Compared to the most advanced fourth generation space station— the International Space Station—although the Chinese space station is relatively smaller in scale, its application benefits are higher than those of the International Space Station. For instance, the proportion of weight of scientific research equipment on the Chinese space station is higher than that on the International Space Station, and the power supply support rate for scientific research equipment is also higher.

At 12:51 on October 30, Shenzhou 19 and Shenzhou 18 astronaut crews met at the space station (Image from China Manned Space Engineering official website).

2 "Tianhe" core cabin.

The core cabin, as the name suggests, is the most central and important component of the space station. The "Tianhe" core cabin, launched on April 29, 2021, provides 50 cubic meters of living space for astronauts. This module is used to manage and control the space station assembly; it supports the docking and on-orbit assembly of spacecraft such as experimental cabins, manned spacecraft, and cargo spacecraft; it provides a place for 3 astronauts to live and work long-term while supporting some in-orbit space science experiments and technology tests; it is equipped with a large robotic arm and a backup airlock cabin. It can install 4 scientific experiment cabinets (3 of which were brought during the launch) and has achieved research accomplishments.

"Tianhe" core cabin consists of a node cabin, living control cabin, rear passage, and resource cabin. Its maximum diameter is 4.2 meters (large column segment), and its minimum diameter is 2.65 meters (small column segment).

Tianhe core cabin.

The node cabin has 3 docking ports and 2 berth ports. Among these, the forward interface connects to the living control cabin, while the left and right directions are specifically used for the docking of the "Wentian" and "Mengtian" experimental cabins. The axial and Earth-facing docking interfaces are used for the docking of the manned spacecraft, with the Shenzhou 19 spacecraft docking at the axial interface. This detail is also reflected in the emblem of this flight mission. The node cabin also has an Earth-facing docking interface for astronauts to exit the cabin early, which serves as a backup airlock exit.

The living control cabin consists of a small column segment and a large column segment. The small column segment has 3 bedrooms and 1 bathroom, while the large column segment is where the crew works, controls, exercises, and enjoys leisure time. The cabin is equipped with the unified control system of the space station, scientific instruments, communications equipment, computer systems, fire protection systems, and air handling systems. In the sealed living control cabin, there are 6 areas configured for work, sleep, hygiene, dining, medical monitoring and insurance, and exercise.

The resource cabin is a non-sealed cabin that provides electrical utilities, propellant, and other essential resources for the space station. The end interface is used to dock with the "Tianzhou" cargo spacecraft to receive supplies from the ground.

The attitude control of the "Tianhe" core module uses an advanced configuration of six torque gyroscopes, which generate control torque by changing the direction of angular momentum, with the advantages of high precision and reliability.

Manned flight mission emblem of Shenzhou 19 (image from the China Manned Space Engineering official website).

Schematic diagram of the "Wentian" experimental module.

3 "Wentian" experimental modules.

"Wentian" experimental module was launched on July 24, 2022, and is the first experimental module of our space station, consisting of three parts: the working module, the airlock module, and the resource module. The working module is equipped with three bedrooms, one bathroom, and can install eight scientific experiment cabinets (four were brought during the launch); the airlock module is used for astronauts to exit the module; the resource module contains a large amount of fuel, a posture control power system, and a large flexible solar array.

China first launched the "Wen Tian" experimental module, then the "Meng Tian" experimental module to dock with the "Tian He" core module because the "Wen Tian" experimental module is a "jack of all trades".

Firstly, the "Wen Tian" experimental module also has unified management and control capabilities for the space station complex, just like the "Tian He" core module. Therefore, if a fault occurs in the core module, the "Wen Tian" experimental module can control the entire space station complex, thereby enhancing the reliability of the overall design of the space station.

Secondly, the "Wen Tian" experimental module has three bedrooms like the "Tian He" core module, and once it docks with the core module, the space station can accommodate two crew members, a total of six people, for short-term simultaneous living, working, and handover in orbit.

Thirdly, the "Wen Tian" experimental module has a more spacious, comfortable, and safer dedicated personnel airlock, which allows astronauts to exit the module more conveniently, ensuring their safety. Starting from the Shenzhou 14 crew, astronauts have exited from this main airlock. The airlock has an exterior square shape and a round interior, designed to install external exposure experimental platforms on its square outer shell with 22 standard payload interfaces.

Fourthly, the airlock of the "Wen Tian" experimental module is equipped with a small robotic arm that can bear a load of 3 tons and is 5 meters long. It can climb onto the "Meng Tian" experimental module, which has no robotic arm, and can be combined with a larger robotic arm to form a 15-meter-long larger robotic arm. Its positional accuracy is five times better than that of the larger robotic arm, and its posture accuracy is twice that of the larger robotic arm, suitable for carrying out the installation, maintenance, and care of various payloads and platform equipment requiring higher precision.

4 "Meng Tian" experimental module

The "Meng Tian" experimental module, launched on October 31, 2022, is composed of a working module, a cargo airlock module, a payload module, and a resource module, serving as a "dream factory" for space research and applications.

The working module of the "Meng Tian" experimental module is where astronauts work and exercise, equipped with many scientific experiment cabinets and exercise equipment, but it does not have bedrooms or bathrooms.

Diagram of the "Dreaming Sky" experimental module.

Its payload module and cargo airlock module are connected to the working module in a nested double-module format similar to Russian dolls, with a cargo airlock module hidden inside the payload module to reduce gas leakage. The payload module is equipped with two deployable exposure experiment platforms and one fixed external exposure experiment platform, providing 24 external standard payload positions. The cargo airlock module is a dedicated passage for cargo exiting the module and is currently the largest cargo airlock module in the world.

The resource module is equipped with large flexible solar wings and a dual-degree-of-freedom sun-pointing device. It can rotate the solar wings around the module axis and solar cell wing axis based on the station's on-orbit motion posture and the angle of the sun.

"Dreaming Sky" experimental module can accommodate 13 experiment cabinets, 9 of which were installed at launch. Its features are as follows:

First, the "Dreaming Sky" experimental module is the place where astronauts conduct scientific research, so it is not equipped with bedrooms or bathrooms to accommodate more scientific experiment cabinets.

Second, the "Dreaming Sky" experimental module is mainly aimed at microgravity scientific research, while the "Questioning Sky" experimental module is primarily used for space life science research.

Third, the most significant feature of the "Dreaming Sky" experimental module is the cargo airlock module, which contains a payload transfer mechanism for automatically transferring cargo out of the module.

The "Meng Tian" experimental module is specially equipped with a small spacecraft on-orbit release mechanism, which, in conjunction with the payload transfer mechanism and the machinery arm, can meet the on-orbit release requirements for small spacecraft of hundreds of kilograms or multiple cubic satellite specifications.

Advanced technology.

Utilizing the advantages of late development, china's space station has adopted numerous new technologies. For example:

The "Tianhe" core module is equipped with a 10-meter long "seven degrees of freedom large space machinery arm" with a load capacity of 25 tons. It reaches the level of the third-generation space machinery arm in the world and can crawl and move on the surface of the module. Whether it's module repositioning, moving large equipment, or the astronaut's own movement, it can be accomplished with this machinery arm. With the coordination of astronauts, complex extravehicular activities can also be completed.

To reduce the cost of manned spaceflight, both the "Tianhe" core module and the "Wenti" experimental module use a regenerative life support system. The water vapor exhaled by astronauts is recovered through condensation, and excreted urine is also recovered and purified for reuse as drinking water and water for daily use. Through regeneration treatment, over 94% of the astronauts' wastewater and air condensation can be reused for daily use and for electrolyzing oxygen. In the future, hydrogen produced during oxygen generation by electrolysis will be chemically reacted with the carbon dioxide exhaled by astronauts to generate oxygen, and waste treatment and reuse technologies will be implemented to further improve the level of material regeneration and recycling, thus minimizing the amount of supplies required for resupply missions and reducing the operation costs of the space station.

The core module for the first time adopts a pair of large area deployable flexible solar panels. Each wing has a deployment length of 12.6 meters, and the total deployment area of the double wings can reach 134 square meters. Compared with traditional rigid and semi-rigid solar panels, flexible wings are smaller in volume, have a larger deployment area, and a higher power-to-weight ratio; once fully retracted, their volume is only 1/15 of rigid solar panels. The solar panels on the other two experimental modules are even larger, allowing for more electricity generation to meet the power demands of the space station.

In addition, the core module is not only equipped with conventional chemical propulsion engines and attitude control engines but also an additional four high-power Hall effect thrusters, which are several times more efficient than chemical propulsion engines, thus effectively saving the consumption of propellants on the core module, reducing the pressure on resupplying fuel to the space station using cargo spacecraft. This enables china's space station to currently launch three "Tianzhou" cargo spacecraft every two years, which is also closely related to the large cargo capacity of the "Tianzhou" cargo spacecraft.

Outlook for the future.

Currently, china is utilizing the capabilities of the space station, microgravity and radiation environment, long-term stay of astronauts in orbit, and the back-and-forth travel between Earth and space as favorable conditions to carry out innovative experiments and application research at the forefront of science, striving for significant breakthroughs in science and technology.

This time, the Shenzhou 19 crew will focus on the planned theme of 'space experimentation,' covering fields such as space life sciences, microgravity basic physics, space materials science, aerospace medicine, and new aerospace technologies, conducting 86 space science research and technology experiments including structural analysis of protein crystals grown under microgravity conditions and non-equilibrium dynamics of soft matter, with the expectation of achieving a batch of scientific results in basic theoretical frontier research, new materials preparation, mechanisms of space radiation and physiological effects of weightlessness, bioeffects in the submagnetic field, and molecular mechanisms.

"Tianwen" optical telescope.

In the future, china's space station system is expected to become the world's first 'mother port' for spacecraft, enabling in-orbit maintenance of other spacecraft in co-orbit. For example, in the future, china will launch the 'Tianwen' space telescope to fly in co-orbit with the 'Tiangong' space station, which, after long-term operation, can fly to the space station as needed, rendezvous and dock with 'Tiangong', where astronauts will carry out activities such as propellant replenishment, equipment maintenance, and payload upgrades, and then separate and return to its original orbit to continue working.

As needed, china's space station can also be further expanded, from a 'T' configuration to a '十' configuration or even a '干' configuration, thereby increasing the operational space of the space station.

In summary, the chinese space station is not only china's space station but also a space station that promotes the development of human aerospace technology and benefits all humanity. In the future, it is expected to achieve research results of significant scientific value and application results of major strategic significance.