Strong observation | These "artifacts" in the return capsule provide protection for astronauts, escorting the spacecraft | return capsule | artifacts
On June 4th, the return capsule of the Shenzhou-15 manned spacecraft successfully landed at the Dongfeng landing site. Photo by Xinhua News Agency reporter Ren Junchuan
From the successful parachute opening of the Shenzhou-5 manned spacecraft after entering the atmosphere to the glorious return of the Shenzhou-15 astronauts aboard the "Dream Fulfillment" mission, this large umbrella, which protected the astronauts from landing safely, witnessed the successive victories of the Chinese people in flying and pursuing their dreams.
"Astronauts returning to Earth from the space station need to go through several processes, including separation, atmospheric crossing, and landing. Among them, the process of atmospheric crossing is very dangerous, with a speed gradually decreasing from 7.9 kilometers per second to about 200 meters per second. After that, the return module will continue to slow down, and this process cannot be separated from a" miracle tool ", which is a parachute." Yu Li, a professor at Nanjing University of Aeronautics and Astronautics and deputy director of the Key Laboratory of "Aircraft Environment Control and Life Support" of the Ministry of Industry and Information Technology, said in an interview with the "Strong Observation" column of People's Daily that the parachute of the return module is divided into three parts: a guide parachute, a deceleration parachute, and a main parachute. ".
"Specifically, the role of the parachute is to pull out the parachute. When the return capsule passes through the atmosphere and falls to a height of about 10 kilometers from the ground, the canopy pops out and opens the parachute. The parachute is pulled out under aerodynamic force; the parachute slows down the spacecraft one step before the main parachute opens to ensure the safety of the main parachute opening; the main parachute is the final stage of deceleration device to ensure the safe landing of the return capsule." Yu Li emphasized that throughout the process, to avoid excessive load, the parachute and the main parachute cannot be opened all at once, and must be closed first and then opened again.
Under what circumstances will the backup parachute of the return module be urgently activated to ensure the safety of astronauts?
![Strong observation | These "artifacts" in the return capsule provide protection for astronauts, escorting the spacecraft | return capsule | artifacts](https://a5qu.com/upload/images/060655bd8f3b436f42d3a88d770afe0f.jpg)
"When the main parachute fails, the backup parachute will be activated in an emergency." Yu Li said that when the return capsule descends from a height of 6 kilometers to 5 kilometers, if it takes less than the scheduled time, it means that the return capsule is descending at a speed higher than normal parachute opening and landing. The system will determine that the main parachute system is working abnormally, cut off the main parachute, and abandon it, automatically activating the backup parachute. At a height of 5 kilometers, it can ensure that the backup parachute completes the work procedure from opening to deceleration, thereby ensuring the safe landing of astronauts.
What other devices besides parachutes ensure the safe landing of astronauts?
Yu Li introduced that the reverse thrust engine and seat system are both landing buffer devices for the return capsule, which are important means to ensure the safe landing of astronauts.
"When the reverse engine descends to a certain height from the ground in the return capsule, the near ground altitude sensor sends a signal, and the reverse engine ignites to generate a reverse thrust impulse, instantly reducing the descent speed of the return capsule, thereby reducing the landing impact load of the return capsule. The seat system inside the return capsule directly supports the astronaut, and within a limited distance after the return capsule touches the ground, it uses the deformation of materials or structures to dissipate the energy, providing shock absorption and buffering protection for the astronaut," said Yu Li.