At 1:59 a.m. on December 17, the Chang’e-5 returner landed safely in Siziwang Banner, Inner Mongolia, as planned, becoming another feat in China’s aerospace history. From the national flag unfurled after the moon landing, to the returner shell made of various high-performance composite materials, to the parachute that helps the returner land safely, high-performance textile materials are indispensable…
Among various aerodynamic deceleration devices, parachutes have been widely used in various aerospace missions due to their light weight, small packaging volume, and high deceleration efficiency. They have become the key to deceleration and safe recovery of various aircraft. Important device.
The parachute system is an important aerodynamic deceleration device for the return landing section of the lunar exploration returner. Its main function is to reduce the speed and altitude to the predetermined level when the returner re-enters the atmosphere for the second time. When within the range, the aerodynamic resistance of the parachute is used to stabilize the attitude of the returner, reduce the descent speed of the returner, and finally make the landing speed of the returner meet the specified requirements.
Research shows that according to the overall layout requirements of the lunar exploration returner, to ensure that the vertical landing speed of the returner is not greater than 13m/s, the parachute system needs to use lateral spring cover opening Parachute mode (similar to the Shenzhou spacecraft), the weight of the parachute system should be no more than 9kg, the weight of the parachute canopy should be about 8kg, and it should be an irregular aerodynamic shape with a stable wing. At the same time, the direction of the force generated by opening the parachute cannot pass through the center of mass of the returner. The connection between the parachute and the returner can only be suspended at a single point. Therefore, the parachute rope also needs to be strong and stable enough. sex.
Parachute composition
In terms of materials The Chang’e-5 returner parachute uses “nylon silk”. The main material is nylon, which is commonly known as nylon. However, the “nylon silk” uses high-performance nylon. The strength of ordinary nylon filament is about 5.0cN/ dtex, and the monofilament strength of high-performance nylon can reach 7.5 cN/dtex. In addition, this layer of brocade silk also needs to be processed with special functions, such as high temperature resistance, flame retardancy, and electromagnetic radiation protection.
In aerospace engineering, ultra-high molecular weight polyethylene fiber (UHMWPEF) is generally used for parachute ropes. It has stable chemical properties, strong anti-aging properties, and super wear resistance. properties and self-lubrication. The ultra-high elastic modulus and strength fiber produced by gel spinning method has a tensile strength as high as 3 to 3.5 GPa and a tensile elastic modulus as high as 100 to 125 GPa. Its fiber specific strength is the highest among all fibers that have been commercialized so far, about 2 times that of aramid, 5 times that of carbon fiber, and 10 times that of steel wire.
About the Chang’e-5 returner parachute system, which has been developed since 2011. It has gone through key technology research and full-cycle model development work, and conducted a large number of ground tests and simulation tests. and airdrop tests, fully verifying the technical status of the parachute system, and undergoing flight test verification of the Moon-Earth high-speed reentry mission. All previous airdrop tests and flight tests have ensured the safe recovery of the returner and ensured the Moon-Earth high-speed reentry. Enter the successful implementation of the return task.
Rocket sled test situation
At 6:42 on November 1, 2014, the returner successfully completed the semi-ballistic jump The flight test of reentry and return safely landed in Siziwang Banner, Inner Mongolia at a speed of 11.7m/s, which is the flight test of “Little Chang’e” in the video. </p
