Chapter 150 The most important question

When Chen Jianfang saw Xu Yuan coming back, a smile immediately appeared on his face and he was very enthusiastic. He hurriedly came out from behind his desk to greet him.

"It's Xiao Xu."

"Sit down quickly."

Xu Yuan didn't seem to be shy at all and sat down on the sofa upon hearing that.

However, before he could state his purpose, Chen Jianfang's voice had already arrived.

"If you have something to say, just say it directly. Don't be polite."

Hearing this, Xu Yuan had no time to hesitate and immediately said, "It's like this, Professor Chen, I want to see the design plans and detailed information about the other parts of Chang'e-1." After saying that, he stared at Chen Jianfang and waited for his reply.

Since there are still problems with the current design of Chang'e-1, the project cannot be completed.

Then he will definitely not let it go. After all, the sooner the problem is solved, the more mature the country's aerospace technology will be.

However, since he currently cannot determine which part has the problem, he can only study all the solutions, and then find the problematic parts and optimize and solve them.

After Chen Jianfang learned that Xu Yuan designed the phase-modulation orbit and completed all the calculations on his own, he already had the idea of ​​giving him more responsibilities.

But thinking about what happened before, I felt embarrassed to ask Gao Duo for people.

Now that Xu Yuan has taken the initiative to see the design plan of Chang'e-1, he can be said to be more than happy to do so.

After thinking it through, he agreed to it without any hesitation.

"no problem."

"It's a good thing that you're willing to learn more. I'll have someone compile a copy and send it directly to you later."

"If you find anything wrong, you can always come to my office to discuss it with me."

"Thank you, Professor Chen. Thank you for your help." Xu Yuan replied immediately.

To be honest, he was somewhat surprised that Professor Chen agreed so readily. After all, when he first came here, the other party did not let him participate in the design of the overall layout of the satellite.

Of course, this saved him a lot of trouble. He then thanked Chen Jianfang and left.

It has to be said that Chen Jianfang really took this matter seriously. Not long after Xu Yuan returned to his workstation, he saw a senior brother delivering the information to him.

Xu Yuan did not waste any time on this. After getting the information, he immediately immersed himself in studying it seriously.

-

In addition to the orbital issue, the Chang'e-1 satellite also includes overall layout design, attitude control, and the most important satellite thermal control issue.

Among the hundreds of lunar exploration activities carried out by humans so far, only the European Space Agency's lunar exploration was successful on the first try, and the success rate of the others can be said to be less than 50%.

This shows how difficult it is to successfully explore the moon.

Therefore, issues that are directly related to the success or failure of satellite launches must be held to the highest standards.

There can be no room for carelessness.

Xu Yuan first looked at the overall structural layout of Chang'e-1. Its main structure basically inherited the structure of Dongfanghong-3, that is, a plate structure of a central load-bearing tube plus a honeycomb panel. The solar wing adopts a single-degree-of-freedom symmetrical double-wing layout. Basically, the design is very reasonable.

After careful research and verification, Xu Yuan quickly ruled out the structural design of Chang'e-1.

As time passed, he finally focused his main attention on thermal control issues.

Satellites before Chang'e-1 all orbited the Earth and were undoubtedly very familiar with the Earth's environment.

But the thermal environment of the Moon itself is not well understood.

In addition, the working mode of Chang'e-1 satellite itself is complex, and facing the situation of alternating hot and cold, the thermal control issue becomes particularly prominent and important.

According to the design of Chang'e-1, the Chang'e-1 satellite orbits the moon once every two hours.

During this process, there is one hour of illumination by the sun and the remaining hour of illumination by the moon.

The temperature difference between front and back can reach 300 degrees.

This means that all instruments on the satellite must adapt to this working environment.

The design of thermal control involves the intersection of multiple disciplines such as thermodynamics, heat transfer and fluid mechanics. After carefully studying the current thermal control design solutions, Xu Yuan found that there are indeed some problems.

According to the existing thermal control design plan, it may be possible to ensure that the instruments on the satellite can operate in a working environment with a temperature difference of 300 degrees Celsius, but when the satellite encounters more severe conditions, it may be a bit stretched.

If any instrument fails due to temperature, it will be a huge disaster for the entire satellite.

It should be noted that the expected working life of Chang'e-1 is one year, but the satellite will inevitably experience two lunar eclipses during this year. The effective duration of the shadow of each lunar eclipse is within three hours, which puts a higher test on the low-temperature discharge capability, temperature maintenance capability and various instrument states of the battery pack that provides energy on the satellite.

"Professor Chen's thermal control design is still too far-fetched. We must find a way to optimize and improve it."

Finally figuring out the problem, Xu Yuan breathed a sigh of relief and analyzed the problem on his own.

Since the progress bar shows the problem, this plan that does not reach 100% cannot be launched, otherwise it will only deal a heavy blow to the development of the country's space industry.

The performance of thermal control must be further optimized.

After deciding on the direction of his next research, Xu Yuan didn't say anything more.

Then it enters the deep learning state again.

When it comes to thermal control design, Xu Yuan can only rely on his knowledge of physics, fluid mechanics, and the memory in his mind to optimize it.

Moreover, he did not expect to optimize the complete design directly. He would just go to Chen Jianfang once he was sure of it.

Professor Gao knew that Xu Yuan was studying other satellite designs, so he would not disturb him. Anyway, Xu Yuan had already completed the calculations for the new orbit design, and there was not much work left. Others in the group could just take over and repeat the exercises to ensure accuracy.

Unlike calculated orbital results, the design of thermal control systems involves more complex disciplines.

Of course, it is not possible to survive in just a few days.

So in the following time, Xu Yuan's life began to become very regular.

Basically, I either stay in my own office at school to do research, or go to the Space Technology Research Institute to look up information.

During this period, Xu Chongxing asked a lot of questions about the situation. After learning that Xu Yuan was studying the thermal control problem of satellites, he immediately had more expectations for him.

After all, apart from the aerodynamic layout design of the stealth fighter a few years ago, he had never seen Xu Yuan's performance in engineering projects anywhere else.

He was still waiting for Xu Yuan to make achievements so that he could show off to Tang Shihong and get his reputation back.

What also puzzled Xu Yuan was that when he met with Chen Yuran, the other party was quite concerned about Professor Chen's situation and even asked him to give his evaluation of his impression of Professor Chen.

He didn't think much about it, but just said a lot of good things about Professor Chen.

Time is like a wild donkey, it runs without stopping.

March comes in a blink of an eye.

After Xu Yuan's research over this period of time, he finally came up with a feasible solution to the satellite's thermal control problem.

……

"During the year that the satellite is in operation, each panel will be exposed to solar radiation."

"So Chang'e-1 does not have a stable heat dissipation surface like the satellites orbiting the Earth."

“So the only option is to cover everything with multi-layer insulation.”

"The layout of the heat pipes is also done by pre-embedding and external pasting, using the heat pipes to achieve isothermal design of the cabin plate, and a large range of internal heat coupling can be performed based on the circumferential heat pipes."

Friday, March 2006, 3, Space Technology Research Institute.

Still sitting in the track design team's seat, Xu Yuan looked at his research results of this period and was generally satisfied with them.

Although there is still some distance to go before a complete satellite thermal control system is built, it has been optimized compared to previous designs.

The progress shown on the panel, which has grown to 70 percent, is the best proof of his achievements.

After reviewing it again and confirming that it was correct, he did not delay any longer, picked up the design draft and walked towards Chen Jianfang's office.

The subsequent continuous optimization of the thermal control system will undoubtedly take up more of his own time. In addition, after the thermal control system is determined and actually manufactured, thermal balance tests will be required for verification. It is a good thing to tell Chen Jianfang as soon as possible.

After nearly a month of getting along, everyone can be said to be very familiar with Xu Yuan.

Whenever they meet members of the project on the road, they will take the initiative to say hello to Xu Yuan.

The main reason was that Xu Yuan only took a few days to solve the track problem, and the news had already spread within the project team.

In addition to his achievements in mathematics, I naturally admire Xu Yuan from the bottom of my heart.

Soon Xu Yuan walked to the door of Chen Jianfang's office. He raised his hand and knocked on the door. Suddenly, a familiar voice came from inside.

"Please come in."

Xu Yuan pushed the door open and saw Chen Jianfang sitting on the sofa drinking tea.

Without even being asked, he sat down directly without showing any restraint.

Chen Jianfang saw Xu Yuan smile immediately and took the initiative to bring him a cup of tea.

"Try the tea I just brewed."

"Thank you, Professor Chen." Xu Yuan took the teacup, put it to his lips and tasted it.

At this time, Chen Jianfang noticed what Xu Yuan was holding in his hand, and asked casually, not knowing what he was thinking about.

"How have you been researching the design of Chang'e-1 recently? Do you have any new ideas?"

"Indeed." Xu Yuan nodded and answered truthfully.

Chen Jianfang: "Tell me about it quickly."

"I think the existing thermal control design is not good enough. During a year-long flight around the moon, I'm afraid it will be difficult for the thermal control system to ensure the normal operation of the instrument in the face of a lunar eclipse."

After hearing what Xu Yuan said, Chen Jianfang felt a little surprised.

He didn't expect that Xu Yuan was researching the most complex thermal control.

He became more and more interested and continued, "Your concerns are indeed justified. There were significant differences in the design of the thermal control solution, but due to various reasons, it has only been optimized to this extent." At this point, it can be seen that he is not completely satisfied with the existing thermal system.

The voice just fell.

He suddenly asked again: "Do you have any good suggestions?"

Upon hearing this, Xu Yuan didn't say anything and directly handed over the design draft he brought.

"I do have some ideas, but I still need your help and reference on how to improve them."

……

(End of this chapter)