Why does China need its own space station?

At 14:22 on July 24, 2022, the first experimental module of China's Tiangong Space Station, "Wentian", was successfully launched from the Wenchang Space Launch Center , accurately entered the predetermined orbit, and is about to complete the rendezvous and docking mission with the core module "Tianhe".

Image source: Xinhua News Agency

Seven key questions will help you understand China's space program's "Wentian" launch.

1

Why launch the experimental module?

China's manned space program has been in operation for 30 years since its inception in 1992. It now has multiple systems including independent launch vehicles, manned spacecraft, cargo spacecraft, astronauts and space stations, and has achieved a huge breakthrough in engineering capabilities from 0 to 1 in multiple fields.

The goal of the new stage is to establish a space station platform where astronauts can stay for a long time, carry out larger-scale space applications, and provide an advanced space technology platform for economic and social development.

In other words: we planted trees before, and now we enjoy the cool air. The foundation of manned space engineering technology capabilities previously laid must be "realized" into various high-tech aerospace technologies to feed back the development of various aspects of science and technology. This process needs to be completed through complex space science experiments in space.

The venue for space science experiments is the experimental cabin needed by Tiangong.

2

Why is it “Asking the Sky” and “Dreaming the Sky”?

Space has special conditions that are difficult to reproduce on Earth, such as long-term stable weightlessness and space radiation, and is rarely disturbed by the Earth's atmosphere and magnetic field, making it convenient for astronomical observations. For example, droplets can easily form a nearly perfect sphere, which is difficult to do on Earth, and this feature can be used to conduct new material experiments.

All test cabinets are designed in a modular way to facilitate experiments and maintenance

Image source: China Manned Spaceflight, Chinese Academy of Sciences)

In order to make full use of the characteristics of the space environment, China will set up 25 scientific experiment cabinets in the Tiangong space station . The two major experimental cabins will also have a certain division of labor and specialize in space life sciences and microgravity science research respectively.

Through the external experimental platform, space radiation and space environment related experiments are carried out. Future survey space telescopes will also fly in the same orbit as the space station to conduct astronomical observations.

"Wentian" and "Mengtian" are the names of the two experimental modules of the space station. Together with the words "Long March", "Shenzhou", "Tianzhou", "Tianhe" and "Tiangong", they create the unique romantic temperament of manned space flight.

3

Why was "Wentian" launched first?

The core reason is that the Wentian laboratory module is very special. It is not only an experimental module focusing on space life sciences, but also another "core module" .

Wentian can be seen as a backup for the Tianhe core module, with the ability to manage and control the space station in a unified manner and equipped with a life support system for astronauts. In the next two astronaut crew rotation phases, a total of six astronauts will stay at the Tiangong space station, with the two major modules each accommodating the work and life of three astronauts.

The huge "Wentian" experimental cabin (Photo source: China Aerospace Science and Technology Corporation)

At the same time, it will also take over the important task of astronauts' extravehicular activities. After docking with multiple modules, the node module of the Tianhe core module must be in a long-term pressurized state, making it difficult to perform extravehicular activities, and its function is replaced by the airlock module of the Wentian spacecraft.

In addition, the experimental cabin also comes with a small robotic arm. Although it is smaller than the existing main robotic arm, it has higher terminal positioning and attitude accuracy, making it easier to carry out complex extravehicular operations.

Therefore, multiple part-time functions require "Wentian" to be launched first.

4

Who will ask the sky?

The Wentian is an absolute behemoth: it weighs 20 tons and is 17.9 meters long, even longer than the Tianhe core module. It is a new record for the length of a single module in the entire history of human manned space flight. So, you can imagine how difficult it is to launch.

Comparison of the Long March 5 basic model and the Long March 5 B model (Source: Memorian-QN)

It will be launched by China's Long March 5B rocket .

Compared with the 57-meter-tall "fat guy" of the Long March 5 rocket, it is a "short fat guy" of about 53.7 meters. It has removed the 11.5-meter-long core second stage, a typical "one and a half (core first stage + booster)" configuration, but uses a larger and longer fairing to protect the spacecraft during rocket launch. The new version of the fairing is 20.5 meters long and 5.2 meters in diameter, enough to protect the huge Tiangong space station compartments.

The Long March 5B rocket is a "powerful weapon" dedicated to the transportation of heavy and large payloads to low-Earth orbit, and is also the "number one contributor" in the construction of the Tiangong space station.

5

Who will take over "Asking the Sky"?

After the launch of "Wentian", my country will achieve its first rendezvous and docking with a space station while humans are present.

Currently, three astronauts, Chen Dong, Liu Yang and Cai Xuzhe, have already welcomed the "Wentian" in the Tiangong. The Shenzhou XIV mission they are a part of is also a milestone mission in the history of China's manned spaceflight. On the one hand, they have to complete the main construction of the Tiangong space station; on the other hand, the crew is composed entirely of the new generation (second batch) of astronauts, which is also the first time in history .

Cai Xuzhe, Chen Dong, Liu Yang (Photo source: China Manned Spaceflight)

Such an important task was completed entirely by "newcomers", which shows that they have completely taken up the responsibility of China's aerospace industry. As my country's space science research becomes more and more in-depth, my country's third batch of astronauts are also being trained, and among them there are also "payload experts" who specialize in research.

6

Where does “Asking the Sky” connect to?

Wentian is a 20-ton giant, and it must dock with the node module of the Tianhe core module in the direction of flight, which has the most comprehensive and reliable multiple rendezvous and docking auxiliary systems. A few days ago, the Tianzhou-3 cargo spacecraft docked here had successfully retired, and finally evacuated from Tiangong and burned in the atmosphere.

After confirming the docking, Wentian cannot occupy this precious docking position for a long time. After all, there will be the Mengtian experimental module, cargo and manned spacecraft docking here in the future. It needs to be rotated 90 degrees with the help of a robotic arm, and the overall shape changes from a "straight line" to an "L-shape" . The reliability and stability requirements of the whole process can be imagined.

The final form of the Tiangong space station (Image source: China Manned Spaceflight)

After the visit of Mengtian within this year, the "T-shaped" structure of the Tiangong space station will be completed and officially inaugurated. In the future, based on the node module, new core modules and experimental modules can be expanded to build a larger space station of 100 tons.

7

What will be done after the “Wentian” docking?

The first task after docking and transfer is to start the life support system and move the astronauts into the experimental cabin. Assemble various scientific experimental cabinets and start the pre-planned experiments of multiple disciplines to ensure that the overall working status of the experimental cabin meets expectations.

It is equipped with experimental cabinets capable of conducting research in life ecology, biotechnology and variable gravity science . It can support research on the response mechanisms of growth, development, genetics, aging, etc. of various types of plants, animals, microorganisms, etc. under space conditions, and effectively promote major frontier scientific breakthroughs in China's life ecology, biotechnology and variable gravity science.

During the Shenzhou XIV mission, the three astronauts will also conduct 2-3 extravehicular walks from here to complete extravehicular operations. The new version of the Tiangong classroom will also be conducted in the brand-new "Wentian" experimental cabin. At the same time, it will also provide the second "bedroom" of the Tiangong for the upcoming Shenzhou XV mission.

The new Tiangong class will be held in the brand new experimental cabin (Image source: CCTV)

Overall, the launch of the "Wentian" laboratory module marks that China's manned space program has officially entered a new stage of space science experiments and technological exploration. A brand-new national space laboratory is about to be built, and China has taken one step further on the road to entering the space age!

This article is produced by Science Popularization China, supervised by China Science Popularization Expo, and written by Space Craft Beer