A New Journey in Space ｜ Recovery Landing System Escort ＂God 14＂ Safe Return

　　At 20: 09 on December 4, 2022, the return capsule of Shenzhou 14 manned spacecraft landed successfully at the Dongfeng landing site, and three astronauts, Chen Dong, Liu Yang and Cai Xuzhe, returned safely. In order to protect the astronauts’ safe return home, shenzhou spaceship has deployed a highly reliable and safe recovery landing system to ensure that the spacecraft’s return capsule will take the last leg of its steady return. Today, we will understand together.

　　Precise height measurement: opening the curtain of "going home""

　　When shenzhou spaceship is flying in orbit, the recovery landing system just "waits quietly" in the return cabin until the spacecraft returns to the altitude of 10km from the ground after passing through the atmosphere.Static pressure height controllerJudge the altitude and send out the start signal of the recovery system, and the recovery landing system will start to work.

　　The static pressure height controller is only one of the equipment of the program control subsystem, and the "behind-the-scenes members" of the whole program control also includeRecovery distributor, pyrotechnic controller, program controller and travel switch.And so on, they have a clear division of labor and perform their duties, just like different areas of the human brain. By sending out program control command signals, they control all the executing agencies in front of the platform to complete a series of actions such as pulling the guiding umbrella, pulling the decelerating umbrella, pulling the main umbrella separately from the decelerating umbrella, lifting the main umbrella, throwing the heat-proof outsole, turning and hanging.

　　Step-by-step parachute opening: "sudden braking" from high-speed rail to marathon

　　The 1200-square-meter parachute can’t be opened all at once when the spacecraft returns to the capsule, otherwise the parachute will be broken by the air. Designers tailored the spacecraft.A set of three-level parachute opening proceduresFirst, open two guide umbrellas in series, and then pull out a deceleration umbrella from the guide umbrella. After working for a period of time, the parachute was separated from the return cabin, and the main parachute of 1200 square meters was pulled out at the same time. This series of actions successfully reduced the speed of the spacecraft return cabin from the high-speed rail to the speed of ordinary people running.

　　In order to prevent the deceleration parachute and the main parachute from bearing too much force at the moment of opening, both the deceleration parachute and the main parachute are adopted.Closing techniqueIn other words, slow down the process of the umbrella rope from folding to spreading, and let the 1200-square-meter umbrella open in stages to ensure that the overload of the whole opening process is within the acceptable range of the astronauts’ sense of body.

　　Thrust Booster: Realizing Soft Landing of Return Module

　　The heat-proof outsole is the "armor" of the spacecraft after it enters the atmosphere. When the main umbrella is fully opened, the spacecraft return cabin will throw away this "armor".Gamma height control deviceGet to work,By emitting gamma rays, the height above the ground can be measured in real time.When the spacecraft’s return cabin drops to a height of 1 meter from the ground, the gamma source at the bottom of the return cabin sends a signal to "command" the four reverse thrusters on the spacecraft’s return cabin to ignite, giving the return cabin an upward lifting force.If the landing speed of the return capsule is further reduced, the astronauts can land safely..

　　Landing point positioning: helping search and rescue to locate quickly

　　In order to ensure the timely search for the return capsule, in addition to arranging a certain number of radars, tracking and measuring the orbit of the return capsule and predicting the landing position, the return capsule is also equipped withAutonomous positioning equipmentTell the search and rescue personnel "I am here".

　　The positioning equipment is mainly radio equipment with the frequency and format specified by the target rescue organization. In order to facilitate the search for the return capsule at night, the "shoulder" position of the spacecraft return capsule is equipped with a flash light, so that the helicopter can find the return capsule at night. When the return capsule falls on the sea, it is difficult to find it in the rough sea. In order to guide the plane and salvage ship to search for the return capsule, the bottom of the return capsule is equipped withSeawater stain. The seawater stain will be released slowly, and the nearby water surface will be dyed bright green for up to 4 hours.

　　Failure plan: fully grasp the life-saving opportunity

　　Because the spacecraft’s return capsule is in a state of high-speed movement during its return, once it breaks down halfway, the outside world can’t take rescue measures, and it is impossible to suspend or restore the program to its original position and start again.

　　In order to ensure the life safety of astronauts and improve the reliability and safety of the recovery landing system, the development team set up9 failure modesIt involves three basic return working procedures: normal return, hollow lifesaving and low-altitude lifesaving. Various backup measures, such as backup parachute device, time controller and three sets of height switches, have been taken to fully guarantee.Safe return and landing of the return capsule in the rocket launching stage, ascending stage, normal return stage and emergency return stage..

　　With such an advanced design, comprehensive function, reliable and safe recovery landing system, shenzhou spaceship can "confidently" rush out of the atmosphere, try its best to protect the life safety of astronauts and make new contributions to the development of manned space flight in China!

　　Source/China Academy of Space Technology

　　Shooting/Liu Zekang Ren Xinyu Song Yongjie