China News Agency, Shanghai, April 16 - Title: the astronauts who landed in the return module landed steadily in the “last meter” home

China News Agency reporter Zheng yingying

On April 16, the return module of Shenzhou 13 manned spacecraft successfully landed in the predetermined area of Dongfeng landing site. Astronauts Zhai Zhigang, Wang Yaping and ye Guangfu reported that they felt good.

The landing process of the return module is not a small challenge for astronauts. After burning, black barrier, parachute opening and deceleration, the return capsule still has a speed of about 8 meters per second. At this time, the astronaut sits in the return module with his back down and face up to the sky. Such a high landing speed will damage the astronaut’s cervical spine. In order to ensure their safety, the impact must be further reduced. How to complete the “last stick” for astronauts to go home safely and comfortably?

The starting “gamma brake commander” carefully calculated

In the last few meters of Shenzhou 13 manned spacecraft’s return and landing, the “gamma brake commander” at the bottom of the return module measured the speed of the return module and its height from the ground. When the spacecraft’s return capsule landed to the predetermined altitude, the “gamma brake commander” accurately issued the ignition command of the landing reverse thrust engine to make the return capsule land smoothly under the action of reverse thrust.

“Gamma brake commander”, developed by 35 Institute of the third Academy of China Aerospace Science and Industry Corporation, is the key equipment of the spacecraft. It has successively served in Shenzhou 8 to Shenzhou 12 spacecraft. The detection method of gamma ray gives it the ability to penetrate the surface vegetation. It can accurately measure the height from the bottom of the return capsule to the surface with an accuracy of centimeter level.

By emitting gamma rays to the surface and quickly capturing the reflected rays, “gamma brake commander” can accurately calculate in the “brain”, extract the altitude and speed information in real time, and issue the ignition command of landing reverse thrust engine at the best time to maximize its cushioning performance.

After landing, reverse thrust engine “millisecond braking”

After receiving the command, this key “brake” was completed by four landing reverse thrust engines.

A slight mistake is a thousand miles away. The “brake” of the re-entry module can’t be stepped on early or late. Only when the timing and duration are the same, can we ensure the smooth and safe landing of the re-entry module.

The designers of the Power Institute of the eighth Academy of China Aerospace Science and Technology Corporation designed a set of “braking” actions: when the return capsule is 1 meter from the ground, four landing reverse thrust engines ignite at the same time within 10 milliseconds, a large amount of gas accumulates in the combustion chamber, forms high pressure, and finally ejects from the nozzle at the tail to slow down the landing speed with reverse thrust.

Although the four engines are small in size and weight, each can produce about 3 tons of huge reverse thrust in an instant. If the four units work together, there will be more than ten tons of reverse thrust. This huge reverse thrust can effectively restrain the falling momentum of the return module, greatly reduce the descent speed of the spacecraft, reduce the overload impact on astronauts during landing, and improve the safety of the last link in the landing process of the return module. (end)