Tiangong 2 will dock China’s first cargo ship

Produced by: Science China
Production: Expo World (Beijing) Education Technology Co., Ltd. Shedton Lin Wenjie
Producer: Computer Network Information Center, Chinese Academy of Sciences

As the first space laboratory in China, the Tiangong-1 target aircraft was launched in 2011 at the Jiuquan Satellite Launch Center. The success of the Tiangong-1 mission means that China’s manned space strategy has entered a new phase. With the successful docking of Shenzhou 8 and 9 , China has mastered the “space automatic rendezvous and docking” technology, which is the basis for building more large-scale space stations.

In September 2014, at the 27th Annual Space Explorers Annual Meeting with Beijing, Yang Liwei revealed that Tiangong 2 is expected to be launched in 2016. Tiangong No. 2 and Tiangong No. 1 launched in 2011 are basically the same in appearance and the same size – Tiangong No.1 has a length of 10.4 meters, a maximum diameter of 3.35 meters and a mass of 8.5 tons.

The launch of the Tiangong-2 will also use the Chang 2 F-type launch vehicle. According to the China Aerospace Science and Technology Corporation, the Chang’e F-type launch vehicle has begun to assemble, and then enters the rocket test phase, and will eventually launch the Tiangong-2 target aircraft next year.

Figure 1. Manned spacecraft docked with the target aircraft

Highlights of the Tiangong 2

Although the Tiangong No. 2 mission is a continuation of the Tiangong No. 1, there are still many bright spots.

Firstly, Tiangong No. 2 inherits the basic framework of the No. 1 target aircraft, indicating that China has mastered the long-term orbital automatic operation and short-term manned spacecraft.

Secondly, the Tiangong No. 2 mission will dock Shenzhou 11 and the “Tianzhou No. 1” cargo spacecraft, which is the biggest highlight of the No. 2 target aircraft. Because “Tianzhou No.1” is the first cargo spacecraft independently developed by China, it is the first time that China has realized the docking of cargo ships and target aircraft.

Third, in order to meet the mission requirements, Tiangong No. 2 was modified on the basis of No.1. For example, China will launch a regenerative life support technology experiment on the No. 2 target aircraft, verifying some basic problems of the astronauts’ long-term on-orbit stay, and laying the foundation for the subsequent realization of the astronauts’ long-term living space station.

In addition to the batch docking of manned spacecraft and cargo spacecraft, Tiangong 2 will also begin a series of scientific research activities during the on-orbit stay, such as carrying a high-sensitivity gamma ray detector, which is part of the international gamma-ray polarization detection project. It aims to study celestial bodies such as black holes in the universe.

Figure 2. Shipyard docking involved in the Tiangong-2 mission

Docking China’s first cargo ship

It can be seen from the strategic plan of China’s manned space flight that the mission of Tiangong No. 2 is still in the early stage of the construction of the space station. Through the Tiangong No. 1 mission, China has mastered the complex docking technology, and has carried out automatic and manual docking respectively. The maturity of the docking technology enables the Chinese astronauts to enter the target aircraft through the manned spacecraft.

However, in addition to the mature manned spacecraft and docking technology, the maintenance of an orbital space station requires the assistance of a cargo spacecraft. The task of this Tiangong No. 2 is to incorporate the cargo spacecraft into the space station operation system and to supply propellant to Tiangong No. 2 through an automatic system.

Figure 3. Through the Tiangong-1 mission, China has mastered the complex docking technology, which enables our astronauts to enter the target aircraft through manned spacecraft.

In addition to the Alliance series manned spacecraft, Russia has also developed the advanced series of cargo ships on the basis of it. After the space shuttle was retired, the United States also developed dragon-type cargo ships and Cygnus spacecraft to provide cargo replenishment for the International Space Station.

At the Zhuhai Air Show last year, the scale model of “Tianzhou No. 1” has been unveiled. From the appearance, it is more similar to Tiangong No.1, but its function is very different.

“Tianzhou No.1” consists of cargo and propulsion, which are the two most important parts. The launching quality is about 13 tons, the weight of the upstream cargo is more than 6.5 tons, and the downstream capacity is about 6 tons. At that time, there will be CZ. The -7 launch vehicle performs the launch mission.

The reason for the demand for downstream goods is that garbage will be generated during the long-term operation of the space station. These wastes need to be carried back by the spacecraft and eventually destroyed in the atmosphere.

In the process of development, “Tianzhou No.1” also took the goal of Russia’s progressive series cargo spacecraft and European automatic cargo spacecraft, and absorbed the problems in their development process, laying the foundation for the high standard of Tianzhou-1.

Making the foundation for the construction of the space station

With the two worlds of manned spacecraft and cargo spacecraft, the construction of the space station will enter the fast lane.

In the construction plan of China’s manned space flight space station, an orbital building with a mass of more than 90 tons will be built in 2020. It can connect up to one cargo spacecraft and two manned spacecraft with a design life of more than 10 years.

Figure 4. Schematic diagram of China’s space station. There are two experimental cabin modules, each on the left and right sides, manned spacecraft and cargo spacecraft. The docking hatch is located in front of and behind the space station, and the core compartment module is in the middle.

So far, only Russia and the United States have orbital space stations. The Russian Mir has fallen into the atmosphere in 2001. It is the first long-term orbital building of human beings and belongs to the third generation space station.

Today, only the International Space Station is in operation, and the space agencies of the United States, Russia, Europe, Japan, Canada and Brazil have taken the lead. Currently, 16 countries and regions have joined the plan.

Figure 5. China’s space station model exhibited at the air show, using a structure similar to the Mir space station, and the truss structure of the International Space Station is greatly different.

Once China’s space station is successfully built, it will become the second long-term space-care station in the Earth’s orbit, which can carry out various space research activities.

After the Tiangong-2 mission, China is expected to launch the test core module around 2018. This is the key structure in the construction of the space station, which is responsible for connecting the various cabins before the space station can be assembled on the track.

At the same time, China is currently developing a launch vehicle for launching the core and experimental cabins of the space station, namely the CZ-5 series. The capacity of the low-earth orbit is more than 20 tons, and the take-off quality is more than 800 tons. The rocket will play an important role in future space station operations and near-Earth orbit missions.

At the same time, the CZ-7 launch vehicle for the “Tianzhou-1” cargo spacecraft will also achieve its first flight in 2016, and will gradually replace the active CZ-2, CZ-3 and CZ-4 launch vehicles in the future, becoming the main force in China. One of the launch vehicles.

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