According to the China Manned Space Engineering Office, the Shenzhou 13 manned spacecraft has completed all the scheduled tasks and will choose the opportunity to evacuate the core module complex of the space station and return to the Dongfeng landing site in the near future.
At present, the Shenzhou 13 crew has made various preparations before the evacuation of the spacecraft, and the Dongfeng landing site and engineering-related systems are carrying out various preparations for the return of astronauts.
From the separation of the Shenzhou 13 spacecraft from the core module of the space station to the final return to the ground, the astronauts will have to experience more than 9 hours. What procedures will be required for astronauts to return to Earth? Let's find out.
Procedure one: get off the "station" and get on the "ship" and evacuate the space station assembly. The Shenzhou XIII manned spacecraft was the first to separate from the space station Tianhe core module. Before separation, astronauts need to close the two-way pressure-bearing module door connecting the Tianhe core module with Shenzhou 13 and formally evacuate the space station. After entering the Shenzhou 13 spacecraft, the astronauts need to immediately change into the cabin pressure suit they wore when they went out on the expedition.
Procedure 2: Be on duty in the return cabin and wait for the return flight. In the return module of the Shenzhou 13 spacecraft, the astronauts also need to make some preparations before returning, including the setting of the return status and the sending of on-orbit instructions.
Procedure three: Before entering the atmosphere, complete the separation of the "two cabins". The front section of the Shenzhou spacecraft is the orbital module, the middle segment is the return module, and the rear segment is the propulsion module. The orbital module and the return module will first be separated before derailment. The engine then starts, the spacecraft gradually descends its altitude, and completes the separation of the propulsion module before entering the atmosphere, and the return module enters the return orbit.
Procedure 4: Enter the atmosphere and experience the test of high temperature vibration and harsh environment. The spacecraft's return capsule descended to about 100 kilometers above the ground, and after entering the atmosphere, it was the most harsh stage of the return process. The air density is getting larger and larger, the return capsule and the air rub violently, so that the bottom temperature is as high as thousands of degrees Celsius, the return capsule is surrounded by flames, the cabin will appear vibration noise overload phenomenon, during which it will experience 4-6 minutes of "black barrier area", the return capsule will lose contact with the ground at this time, but the ground can be tracked by sweeping radar and other ways.
Procedure 5: Open the parachute and land steadily. At an altitude of about 10 km above the ground, the return capsule will open the guide parachute, deceleration parachute and main parachute in turn, and throw off the heat-proof outsole. When it is about 1 meter above the ground, the reverse thrust engine is started, and the descent speed is reduced to about 2 meters per second, and finally the return capsule lands safely.