October 24, 2021

Demystifying the first launch of the Long March 5 details: thrilling three hours and 10 seconds countdown interrupted 3 times

According to statistics, the probability of successful launching of rockets in various countries is 50%. Which half of the probability will this launch be?

On November 3, 2016, a day worthy of permanent commemoration by the Chinese space industry. On this day, at the Wenchang launch site and 3 kilometers from the launch tower, I experienced the entire process of the first launch of the Long March 5 launch vehicle. How many times I have seen the launch, even I can't remember it myself. Only this time, it is the most heart-wrenching - this is the first launch of the Long March 5 launch vehicle.

01 Commander Hu Xudong's location is in the center of the hall. He has a password, and a dozen system commanders follow the repeated passwords, and the confident and thick voice echoes in the hall. Hu Xudong, born in 1980, appears to be much older than the actual age. Ten days ago, I and I hurriedly met one side. At that time, he only said one sentence: "This start must be successful. Its significance is extraordinary. If it is not successful, it will be too big for China’s spaceflight. "His words made me immediately give birth to a prayer: Long March 5, you must not drop the chain, let the other half probability go to hell!

Looking out over the tower 3 kilometers away, like a gorgeous palace, "Fat Five" is like a beautiful princess waiting to marry, full of magical charm. I said in my heart: Dear, safe all the way. When I turned back to the command hall, the first "stunning" came to me, and the clock just went to 10:30. Hu Xudong's password is powerful and slightly low: "The numbers keep the state, and they don't enter the -7 hour program." In the hall, a small shock. "Keep the state, don't enter..." Everyone understands what it means.

The first process of the first launch of the Long March 5: the countdown is interrupted 3 times in 10 seconds.

Data Sheet: The explosion of the Long March V engine

The launch towers 1, 3 boosted the suspected liquid oxygen leak on the rocket. Hearing the word "leakage" is a purely amateur, and his heart will suddenly tremble. The most worrying aspect of the filling process is the fuel leak. I have heard too many accidents in this area. Liquid hydrogen liquid oxygen is a very low temperature flammable and explosive fuel. They are filled into the rocket's belly and are easily vaporized. Plus the launching area is three high (high salt spray, high temperature, high humidity), it is more difficult to serve. Leak out, think about how terrible it is.

Half of the people in the command went out of the hall and went to the small meeting room for an emergency meeting. They should carry out troubleshooting according to the "double five" zeroing standard unique to the aerospace. When the two deputy chiefs rushed to the 101-site site to investigate and troubleshoot the fault situation, the small conference room had long been arguing with red face. This will be like a negotiation between the two parties. When everyone is still arguing over the "failure", the stationmaster Tang Gongjian has pointed out the most pressing question at the moment: Is the program stopped or continued? When the experts agreed to return to zero, an hour has passed. The launch window changed, 01 commander Hu Xudong issued the password: "Reset ignition time is - 19:01:00."

The program can go down and the atmosphere in the hall is light. I secretly prayed again that there would be no more accidents. 15:48:20, the flow of liquid hydrogen is completed. The commanding members seemed to be relieved, easily stood up, transferred to the battlefield, and took a seat at the 10th floor command hall. At 17:00, I went to the scene. The huge exhaust sound and the whistling wind made me suddenly feel a little cold. This is the kind of "cold" I have already known. A month ago, I have been here, and Li Jianjun, who was the "housekeeper" of the filling system, brought me. He introduced me to the low-temperature fuel system. Along with my voice, there is also a Jiangnan woman with a thin face. Her name is Chen Hong, a high-level student of the Department of Thermal Physics of Zhejiang University. This seemingly showy Hangzhou woman has a kind of power that is beyond ordinary people. In order to develop low temperature fuel systems and storage tanks, the team she led has spent more than 10 years. "A decade of grinding a sword", I can read hard and hard from the freckles on Chen Hong's face.

Back to 508, see the station full of people. I am amazed in my heart: What happened again? The door of the small meeting room is tightly closed. My legs suddenly sank and I went to the command hall and heard that: the first-stage cycle pre-cooling failed. Just the word "failure", you can predict the seriousness of the situation. “Suspend the liquid oxygen discharge and suspend the kerosene filling. The system keeps the state and does not enter the -1 hour program.” The experts urgently discussed the countermeasures: “This time the temperature will not drop, we will terminate.” “You do it first, the last one. It’s only half an hour.” “It’s only half an hour. After half an hour’s work, it’s not enough, so I have to give up.” The so-called window is a suitable time width for the launch of the launch vehicle. The entire window was only 2 hours and 40 minutes, and the delay was 1 hour in front, leaving only 1 hour and 40 minutes. Now it’s been -1 hour, stop again, is the window still ok? If you lose the window, carefully feed the things in the rocket's belly, let it spit out, the whole procedure has to go against it. Anything that is reversed is very difficult, like a ship going upstream.

At 17:36, the hydrogen circulation pump supercharged pre-cooling and discharge pre-cooling effect is still not good... The 01 commander issued the password of “the number is maintained, and the program is not entered for -1 hour”. "If it is not 19:30, the pre-cooling of the first-stage liquid hydrogen engine is still not normal, consider entering the termination of the launch procedure. This is the decision of the command." Chen Hong recorded this paragraph, I read it three times afterwards, read the first At 2 times, the eyes tidal: termination of the launch procedure means more than 400 liquid hydrogen, more than 500 liquid oxygen needs to be vented, and the launch site will undergo an extremely severe test. China Aerospace will face unprecedented technical challenges.

At 19:33, good news came: the temperature of the primary hydrogen pump shaft finally dropped. 01 Commander issued a thankful password: "Set the ignition time: 20:40:00." When I heard the news, the air that solidified in the command hall suddenly seemed to inject a clear stream, and it seemed to be able to hear the glaciers. The sound of "squeaky" when it is opened. The slightly chaotic order returned to normal. I breathed a big breath, feeling nervous and wrinkled into a mess of hearts, and instantly bloom like a flower.

And Chen Hong, are they decompressed? Look at Chen Hong’s record at the time: another new request. This is the first time that the liquid hydrogen reflux system has been used for the first time in decades since the Long March 3 in the 1980s! ! ! Please understand the pressure and weight from Chen Hong's three big "!!!". I don't know how Chen Hong's thin shoulders have withstood this tremendous pressure. As a female soldier older than her, I want to express her deep respect to her. In addition to the military ceremony, she wants to give her a big hug. Her leader told me: "Chen Hong is a woman who is happy with her work, and the office is her home." According to worldly understanding, will she be as disabled as many women with strong careers? Later, I realized that my fears were completely redundant. She had a husband who loved her very much, and a son she loved very much. However, the son suspected that her cooking was not good, she would rather go to the cafeteria than to eat the rice she made, and the few dishes her son loved were her husband's craft. But she said that she would clean up the housework and wash and wash the quilt. As a woman, she is happy.

At 19:55, the first stage of hydrogen injection begins. The filling flow rate is increased to 2.5 times the set flow rate, and the liquid level does not rise. The flow rate has increased again, the safe flow rate has been exceeded, the liquid level has not risen, and the open and exhaust valves are released. These “dancers on the tip” do not know how their own pressure is discharged. I know that Chen Hong likes to walk to decompression. At this moment, she sat motionless in the position of command, she can not now use to walk to ease their pressure, can only put pressure on the head, what should I do? I can guess that there is an invisible foot in her brain at the moment, flying, and the toes are pointing to the moment of victory that we all expect. The liquid level stabilized at the final level until 5 minutes and 30 seconds before the shot. At this time, I heard the password: "Hydrogen is good!" In the glass room of the hydrogen control room, a burst of applause broke out instantly: "It is too difficult!" Can we understand the meaning of these 7 words?

It is very close to ignition. I don't know how to choose. It is the majestic appearance of the "Fat Five" fire on the 2nd floor of the open space, or stay in the command hall. While hesitating, I heard the 01 commander Hu Xudong Hong Liang but the slightly low voice rang again: "Suspend the entry into the -3 minute preparation process, set the ignition time to be: 20:41:17." At the moment: 20:38. This "suspension", once again makes people nervous to hold their breath. The core primary oxygen connector did not fall off. Another fault, need emergency response. I was so nervous that I didn't dare to listen again, I felt that my chest was blocked. Hu Xudong was extremely calm: "Suspend the -2 minute preparation process and set the ignition time to 20:41:56." The window is set again.

At this time, I suddenly remembered a detail when interviewing Hu Xudong: Not long ago, Hu Xudong and his lovely little daughter video call. That was his most happy moment, but this moment was pitiful. In the video, he heard the baby's tender and sweet voice: "Dad, you see, I bought a new watch", that "Dad" don't mention warm heart. Can be fixed and fine, the "watch" on the back of her daughter's hand, the original is the tape left by the hanging needle, he snorted. It turned out that my daughter was hospitalized because of illness, but he didn’t know at all... Now, is this still in his mind? No, it is completely impossible. At this moment, he can't be distracted, his heart, all in the password of each program.

When the program entered -90 seconds, Wei Kang, the 120 commander who was called "Golden Finger", issued the password for "transfer". His voice just fell, and someone reported: control the main control computer error! Before he could react, Wei Kang once again shouted the report. At this time, there was less than one minute from the ignition of the launch: "01, terminate the launch!" Wei Kang, the password, was later ridiculed: This is "the most cattle in the history of China's space history." Password, no one." At this moment, I couldn't help but feel flustered for Hu Xudong, because his instructions became colloquial: "How do you do it?" Wei Kang replied: "01, wait a moment." The hardest time in the world? Afterwards, I heard that if this launch is not manual, everything is automated and may not succeed. It seems that the last thing that can really be relied upon is people, not machines.

After ten seconds, the 120 commander shouted: "01, okay." Really good? Do not. This time, the magic is magical when it enters the countdown for 10 seconds. The 01 commander still has 3 interruptions while reading "10, 9, 8, 7, 6...". This is also unprecedented in the history of Chinese aerospace. One time: the professional guidance report: "There is still no number." One is the attitude control professional report: "The attitude angle deviation has not yet." Wei Kang again shouted: "01, wait a moment. "A little wait. These simple words, fiercely listen, like sick sentences, can be accurate to them. I want to tell all those who want to watch the rocket launch. If your heart is not good, be careful, please don't.

-6 seconds posture control professional report said: "With!" Wei Kang also followed the report: "01, well." At this moment, 01 commander Hu Xudong once again decisively reached the password: "C31 reset current time is -10 seconds "Nothing, the program returned to -10 seconds." They just went back and forth several times in minutes and seconds. This is the moment of launching the ignition. This time, Hu Xudong’s password was as calm and confident as every previous password. Although there was a little hoarseness, it was very hoar, isn’t it? "5, 4, 3, 2, 1, Ignition!" The people who watched the launch outside, followed Hu Xudong's loudly countdown, and the sound and waves of the entire launching field were smooth and uniform: 3, 2, 1— -ignition!

20:43:13.13998 seconds, the Long March 5 carrier rocket ignited, a huge mist flow from the rocket's base spewed out, then a dazzling fire, the arrow slowly left the base, solemnly lifted off, a fire dragon tearing open the gap Raging with the dust... After about 30 minutes, there was a voice in the command hall: the first flight of the Long March 5 carrier rocket was a complete success!

Now, I can finally applaud the Chinese astronauts.

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