Chapter 977: Mr. Gao is looking through the documents? Then we can rest assured (there are 2 more chapters in the evening)
"Oh my! Chief Engineer Gao is really amazing. He can guess this. That's what's going on! Because of the solar power and camera issues, we changed to three-axis stabilization, but the problem now is that it can't stabilize." Engineer Zhu was very surprised. What is an expert? This is it. They all answered quickly!

These two problems are fatal to photographic satellites.

As long as the solar panel output power is not enough, then no matter how big the battery is, it will be useless.

Poor photographic imaging is also a fatal problem. If it is a pure meteorological satellite, it is actually better. Spin stabilization can also be used to image through a multi-channel scanning radiometer, such as our early Fengyun-2. However, if a slow-scan camera is used, it will be troublesome.

"Mr. Gao, to be honest, it's not just the three-axis stabilization, even the seemingly simple control of the solar panels is a bit difficult. It's easy to unfold the two sides, just use springs and other parts to pop them open, but there is one place that is very difficult, that is the place where the solar panel is connected to the satellite, this place is difficult to deal with. Our satellite has a working posture requirement..."

When a satellite takes a photo, it must have a specific posture. This posture is the top priority. It is impossible to adjust the satellite's posture for the direction of the solar panels. That would be counterproductive. The working fluid of the satellite's engine is very precious and is directly linked to the life of the satellite.

The reason why satellites have a short lifespan is that, except for those short-life satellites that are designed to be recoverable, most medium and high-orbit satellites do not break down in the sky. These things are difficult to break down. The main problems are two - either they are out of power or they are out of gas.

It is easy to understand that there is no electricity, but out of gas means that the working fluid of the attitude adjustment engine has been consumed. For example, the spacecraft of the Citigroup before Gao Zhendong's time travel was emitting helium and carried people into space but did not dare to carry people back, because it was worried about similar problems.

The satellite's attitude adjustment and orbit maintenance all rely on this thing. Once the working fluid is exhausted, the satellite will be unable to maintain its working attitude and will slowly fall out of orbit, which means it will be dead.

The reason why all the major space powers later tried to develop fluidless engines, no matter how low the thrust was or how unreliable they seemed, is that the problem lies here. It has nothing to do with the general propaganda of heading outside the solar system, as the road is too long and people cannot live that long. The main reason is that this thing is very useful for the actual service life of the spacecraft.

Therefore, saving working fluid is definitely the top priority.

“… In this case, the solar panels must be able to control their orientation. This brings up a problem. Orientation control relies on motors, but the size, weight, and accuracy of the motor transmission devices we have are a bit problematic. The three-axis stabilization system itself takes up a lot of space and weight.”

Unlike spin stabilization which can be achieved with a simple spinning engine, three-axis stabilization requires the addition of a lot of equipment to achieve stability.

The solar panel control mechanism may seem simple, but in fact, all the factors combined together pose a considerable challenge to the already limited transportation capacity.

"Although solar panels are weightless in space, their mass is still there. If we want to rotate them, we must consider the moment of inertia. In short, the transmission ratio of the transmission mechanism should be as large as possible, so that we can use a miniature motor to drive it. However, the transmission ratio of the transmission mechanism we have is too large, and the head cannot be reduced. It is equivalent to the miniaturization of the motor in vain, which is a headache."

As he spoke, he watched Gao Zhendong flipping through documents.

What does Mr. Gao mean by this? Is he impatient to listen any further?

Gao Zhendong took out a document from the drawer, carefully covered the rest of it, and then left the remaining parameter sheet as if it was a skylight, and then he put it on the table and pushed it to him: "Engineer Zhu, can you guys use the transmission machine with these parameters?"

This is why Gao Zhendong laughed in his heart at their sharp noses. As soon as the relevant research was started, they came to him on their own.

This method made it impossible for Engineer Zhu to pick up the document, but he didn't care about it. What was important was what was written on it.

He stretched his head over with great effort and looked at the skylight on the table, his expression becoming more and more surprised.

Although the size of this thing is a little bit big, there is really no problem with it otherwise.

"The load, transmission ratio, weight, layout, and structure of this thing are simply designed for us! We can even save an angle sensor! Although it is a little bigger, it is already very good and very suitable. We just need to adjust the layout." With the parameters that can be seen in this sunroof, what else do we need a bicycle for? If there is a problem, it is because we did not arrange it well!
Moreover, the transmission ratio of this transmission machine is strictly corresponding, and it has ultra-high precision and a large transmission ratio. Combined with the stepper motor control system, it can directly calculate the rotation state of the output shaft with relatively high accuracy.

Seeing this, he looked at Gao Zhendong with a little doubt: "Mr. Gao, have you prepared this for us a long time ago?" What is a quick answer? This is a quick answer, even all the answers are ready.

For a moment, Zhu Gong even suspected that Gao Zhendong had sent someone to keep an eye on them. But then he put this unreliable idea behind him.

Gao Zhendong shook his head: "No, this was originally prepared for another project, but I think you should be able to use it. This thing is still in the project establishment and development stage, but I am sure it can catch up with your progress."

Originally it was, but in this world line, it really isn’t.

"That's great, we'll be waiting for your good news! Thank you so much!" Engineer Zhu was eager to try. Although the three-axis stabilization has not been solved, at least the control of solar panels and even a considerable part of the machinery that needs to be driven in space can be said to have found the ultimate answer here. As for whether this can be done, he is not too worried. Judging from the past experience of Chief Engineer Gao, his words are highly credible.

"Then let me continue with the three-axis stabilization. It's like this..."

Gao Zhendong knew that the explanation of three-axis stability was a long one, so he simply interrupted him.

"Just tell me the details. What part is the problem? I'll see if I can fix it. If not, there's nothing I can do."

I was stunned by Gao Zhendong's direct words. Yes, even though Chief Engineer Gao did not participate in any specific work related to the satellite, he was able to directly answer the details related to spin stability. It seems that he must have studied the stable system, or at least understand it. Why am I wasting his time by talking nonsense here?

Just state the problem directly. If it’s feasible, make this a one-time deal. If not, quickly look for the next one.

"Hey, that's good."

Engineer Zhu organized his words: "After we rejected spin stabilization, we used gravity gradient coarse stabilization plus three-axis precise stabilization, and used solar sensors and gyroscope sensors to provide a stable reference. Then we discovered a new problem. The volume and weight of the gyroscope, the four flywheels for flywheel stabilization, and other equipment and systems related to three-axis stabilization seriously exceeded the standard, especially the weight..."

Gravity gradient stabilization is actually to extend a long pole in the direction of the satellite facing away from the earth, so that the earth's gravity will automatically pull the pole perpendicular to the earth's surface, naturally stabilizing the spacecraft. The accuracy is not high, but it is very useful as an auxiliary means, anyway, no fuel is required. Many spacecraft have a seemingly useless pole or long rack, but it is mainly for this purpose.

For specific effects, see tying a magnet with a rope and bringing it close to another magnet. The rope will be pulled straight by the magnetic force and point to the magnet being approached.

"Well, this plan is indeed good. If the flywheel is three-axis stable, then the weight and volume of the flywheel will be relatively limited. The only thing left is the gyroscope?" Gao Zhendong asked.

"Yes, the flywheel is determined based on the design conditions. In order to ensure the effect, we used four in total, three in the direction and one in the diagonal direction. This leaves little room for the gyroscope. The mechanical gyroscope that meets the accuracy standard is too large and heavy. The problem now is that it can't be installed at all..."

Before he could finish his words, he saw Gao Zhendong with surprise starting to flip through the pile of materials again.

Is there more?

Gao Zhendong did not open the skylight this time, as this thing was originally intended to be used by them right away.

"This should be enough for you, right? This is the laser gyroscope that our colleagues at the original research institute are currently researching and has basically succeeded. Take a look. You don't have to worry about this one, as it's almost only waiting for acceptance. You can even ask them for a few now." As Engineer Zhu looked at it, Gao Zhendong smiled.

"Enough! Enough! That's enough! It's a perfect direct replacement, light and small, and it doesn't have the wear and tear problem of the mechanical gyroscope! Mr. Gao, I'll go find them right away!"

Engineer Zhu even wanted to run to the original research institute. Compared with the control of solar panels, three-axis stable control was the problem they were more worried about. After all, solar panels were really difficult to control, so it might not be a bad idea to install them a little bigger.

Gao Zhendong grabbed him and said, "Now that you're here, you still want to run away?"
"Don't worry, I'll give you two suggestions, you can consider them."

"You tell me, and I remember."

Hey, Chief Engineer Gao has a suggestion, so let’s put the original research institute aside for now. Engineer Zhu immediately sat back on the stool.

After all, the things there are ready-made and cannot be saved, and Chief Engineer Gao’s unknown suggestions may be more important.

"I suggest you bring a device up there, a magnetometer."

"Magnetometer?"

"Yes, measure and verify the strength of the Earth's magnetic field in space. These data can be used by spacecraft to determine their own positions. Moreover, this device is light in weight, does not consume much power, and does not have high requirements for temperature. Although its accuracy is a bit low, it is very useful as an auxiliary position-sensitive device. This satellite is equivalent to laying the foundation for subsequent satellites. Moreover, the magnetic field is very useful..."

(End of this chapter)