Original title: Yang Liwei “unbearable” 26 seconds Chinese rocket development team conquered
China News Service, Jiuquan, October 16th, title: Yang Liwei “unbearable” 26 seconds Chinese rocket development team conquered
Author Ma Shuaisha Guo Chaokai Wang Ying
On October 16, the Long March 2 F Yao 13 carrier rocket successfully launched the Shenzhou 13 spacecraft, and the China Space Station ushered in a new “business trip” trio. The live TV footage showed that the three astronauts were more relaxed when they lifted off.
Such a relaxed picture reminds people of the “unbearable” 26 seconds that Yang Liwei, China’s first astronaut into space, experienced. In the article “A Day in Space”, Yang Liwei recalled, “The painful feeling is getting stronger and stronger, and the internal organs seem to be broken. I can hardly bear it and feel that I am going to die.”
How to make Chinese astronauts no longer suffer such pain and eliminate the hidden danger of rocket failure? To solve the problem, we must first know what the source of the problem is. After calculation and analysis, the test personnel of the Beijing Institute of Strength and Environment affiliated to the China Aerospace Science and Technology Corporation believe that the “root of disease” may be in the oxidizer. When the vibration frequency of the fuel in the oxidizer is close to the vibration frequency of the rocket structure, it is likely to be A divergent vibration that couples the structure and the liquid occurs. The source of Yang Liwei’s “unbearable” is resonance, which was once a world-class space launch problem. Not only the rockets developed by China have this problem, but also foreign rockets. As early as the 1960s, during the launch of the American Hercules rocket, there was a vibration that lasted 30 seconds. French rockets have experienced similar problems, which affected the lifespan of satellites.
After the theoretical analysis, the test personnel of the institute then carried out the full arrow modal test and the liquid characteristic test of the oxidant pipeline. During the test, the tester first injects fuel into a fuel pipe, and then loads the fuel pipe with vibrations of different frequencies to observe the vibration frequency of the fuel. If the laboratory data is consistent with the full-arrow modal test data, it can prove that the tester’s inference is correct.
After more than half a year of investigation, analysis, and calculations, the testers finally concluded that the problem lies in the POGO vibration of the rocket. This conclusion confirmed their previous speculation.
After finding the root cause of the problem, the research and development team of the First Academy made improvements. Originally, the booster accumulator of the Long March 2 F Yao 5 launch vehicle was equipped with two bellows. When the Long March 2 F Yao 6 launch vehicle, the bellows were reduced. To one. This improvement has achieved obvious results. When the Long March 2 F Yao-6 carrier rocket launched the “Shenzhou VI” spacecraft, the vibration magnitude and vibration time were reduced, and the astronauts reported that the vibration was much lighter.
“Much lighter” means that the research direction is right, but the problem has not been completely solved. To this end, the development team continued to optimize the design and changed the booster accumulator to a “variable energy accumulator”, using accumulators with different PV values during different flight periods. The device can absorb the energy generated when the fuel vibrates. , Changing the vibration frequency of the fuel, the rocket no longer produces POGO vibration.
After the Long March 2 F Yao-7 carrier rocket launched the “Shenzhou VII”, astronaut Nie Haisheng responded, “The rocket we are riding on is very comfortable and hardly feels vibration.” A short sentence means that the first hospital has overcome the resonance. Difficult problem.
The life safety of astronauts when flying into space is closely related to rockets. From “unbearable” 26 seconds to “almost no vibration”, behind this is the rigorous analysis, long-term efforts and continuous breakthroughs of the rocket development team. (over)
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