The 26 seconds that once made Yang Liwei "unbearable" Why is it no longer bothering today's astronauts

Beijing Space City, October 16 (China Youth Daily, China Youth Daily reporter Qiu Chenhui, trainee reporter Yang Jie) On October 16, the Long March 2 F Yao 13 carrier rocket successfully launched the Shenzhou 13 spacecraft, and the Chinese space station ushered in a new "space travel trio." Live television footage showed the three astronauts looking relaxed as they lifted off.

Such a relaxed picture reminds Chang Wuquan, the overall chief designer of the Zheng-2 F Yao-13 carrier rocket of China Aerospace Science and Technology Corporation, reminiscent of the "unbearable" 26 seconds experienced by Yang Liwei, the first astronaut in China to enter space. In the article "A Day in Space", Yang Liwei recalled, "The feeling of pain is getting stronger and stronger, and all the internal organs seem to be broken." I could hardly bear it and felt like I was dying. ”

Chang Wuquan told reporters that 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, the American Hercules rocket had a vibration that lasted for 30 seconds during launch. French rockets have had similar problems, and satellite life has been affected.

(Long March 2F YaoXIII carrier rocket before launch, Gao Nan photo/Courtesy of the First Academy of China Aerospace Science and Technology Corporation)

How to make Chinese astronauts no longer bear such pain and eliminate the hidden danger of rocket flight failure? After calculation and analysis, the testers of the Beijing Institute of Intensity and Environment, which belongs to the First Academy of China Aerospace Science and Technology Corporation, believe that the "root of the disease" may be in the oxidant, and when the vibration frequency of the fuel in the oxidant and the vibration frequency of the rocket structure are close, it is likely that the divergent vibration coupled with the structure and the liquid will occur.

After the theoretical analysis, the test personnel of the institute then conducted a full-arrow modal test and an oxidant pipeline liquid characteristic test. 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 coincides with the full arrow modal test data, it can be proved that the tester's inference is correct.

After more than half a year of investigation, analysis, calculation, etc., the testers finally concluded that the problem was that the rocket generated POGO vibrations. This conclusion confirms their previous speculations.

Chang Wuquan said that after finding the root cause of the problem, the research and development team of the First Academy made improvements, and the original booster accumulator of the Long March 2F Yao-5 carrier rocket was equipped with two membrane boxes, and when the Long March 2F Yaoliu carrier rocket arrived, the membrane box was reduced to one. This improvement has obvious results, when the Long March 2F Yaoliu carrier rocket launches the Shenzhou VI manned spacecraft, the vibration magnitude and vibration time are reduced, and the astronauts reflect that the vibration is much lighter.

"Much lighter" means that the research direction is right, but the problem is not completely solved.

Chang Wuquan told reporters that the development team continued to optimize the design, changed the booster accumulator to a "variable energy accumulator", and used a accumulator with different PV values at different flight times, which can absorb the energy generated when the fuel vibrates, change the vibration frequency of the fuel, and the rocket will no longer produce POGO vibration.

Later, after the Long March 2 F Yaoqi carrier rocket launched the Shenzhou 7 manned spacecraft, astronaut Nie Haisheng responded, "The rocket we are riding on is very comfortable, and we can hardly feel the vibration." ”

A short sentence means that the first court has overcome the problem of resonance.

"The safety of astronauts' lives when flying into space is closely related to the rocket, from 'unbearable' 26 seconds to 'almost no vibration', behind which is the rigorous analysis, long-term efforts and continuous breakthroughs of the rocket development team." Chang Wuquan said.

Source: China Youth Daily client