Siheyuan: I eat melons while doing scientific research

Chapter 1230 Soldiers' Track (5k)

If Gao Zhendong's words were posted on a forum decades later, he would at least receive a response like "It's a pun, I'll deduct your money."

However, it has obviously not reached that point yet. Instead, the comrades have become completely helpless. What does this mean?
Even the leaders of the Defense Work Committee, who were experienced in many battles and well-versed in military affairs, did not understand what Gao Zhendong meant.

He thought about it and decided that the only thing related to satellites and to "evil ways" was reconnaissance satellites.

"Zhendong, are you talking about reconnaissance satellites? Aren't they already made?"

Gao Zhendong shook his head: "No, I mean the satellite orbit. My opinion is that for a long period of time, the military will still follow the basic rule of standing high and seeing far, so anything related to the military that can be put on orbit should be put on orbit!"

After hearing Gao Zhendong's words, the comrades felt a little amused. Comrade Zhendong's position is getting higher and higher, so why is he becoming more and more naughty?

The leader of the Defense Work Committee burst into laughter. There was nothing he could do; he really couldn't help it.

Although homophonic puns were played out decades later, they are still very effective now. This is mainly because his comrades did not expect him to do this. This can be considered the effect of the contrast in identities.

"Okay, okay, what a good soldier, and also a track. From the commander's point of view, it should be a trick, but from the perspective of you scientific and technological workers, it can really be said to be this 'track'. Ah, I forgot that you were also a commander, so you can use both." Although Gao Zhendong made a little joke, from the perspective of the leaders of the Defense Work Committee, it really makes sense, just put everything on the track.

But some things cannot be put down, they are too sensitive.

"So just tell me, what are you going to put on this 'track' you mentioned?" the leader of the Defense Work Committee said with a smile.

Gao Zhendong also laughed: "There are some things I would like to put on it, but I guess everyone is too embarrassed to put them on it..."

Those who understand this, including the comrades working on satellites, all understood and were happy. Who wouldn't want to? But it's really not appropriate to put it up there. It might open a Pandora's box, and comrades all know that with our current level of technology, it's not a good thing to open this box too early, because we will suffer losses.

"So, my idea is to advance it with both military and civilian efforts, one for military use and the other for civilian use."

"Well, the military photographic reconnaissance satellite... no, the civilian resource satellite, is doing pretty well now, so we don't need to work on this for the time being," said the leader of the Defense Work Committee.

Gao Zhendong shook his head: "No, we have to continue this, and we have to do it in two directions."

Gao Zhendong overturned the first sentence, but the leader didn't take it seriously at all: "Why? Tell me."

"For reasons such as communication, photography, and rocket capacity, we currently use low-Earth orbit for semi-real-time reconnaissance satellites. In fact, this is not the best choice. The best choice should be a sun-synchronous orbit. I think the comrades working on satellites are very clear about this."

Among the comrades working on satellites, a comrade in charge of related work nodded and said: "Yes, for satellites such as photographic reconnaissance, resources, and meteorology, the sun-synchronous orbit is indeed a better choice, but the altitude of this orbit is 600 kilometers to 6000 kilometers. Our current technology is limited, so we have to choose the low-Earth orbit."

With the explanations of the technicians from both sides, the leaders of the Defense Work Committee did not take it seriously and thought it was no big deal: "Is that so? It doesn't matter. There are also comrades working on launch vehicles with greater carrying capacity. I guess you are not idle either. We will develop slowly and we will always achieve better results. Don't feel sorry. For us old-fashioned people, this is already very good now, haha."

He was not just saying this to comfort everyone; he was telling the truth. Apart from anything else, just the time of the torrential rain in Haijiang, the timely warning and advance preparations given due to satellite photos had completely paid back all the investment in the satellite, and it was a huge profit. As for the other gains, they were all incidental.

Besides, compared with the bullet I shot for the Russians, it’s equivalent to not spending any money.

The comrades all nodded. This made sense. Even when Gao Zhendong himself brought up this matter, he was not blaming himself or feeling regretful. He was merely clarifying the future development direction.

"So what's the other direction you're talking about?"

"Returnable photographic reconnaissance!" Gao Zhendong's answer was beyond everyone's expectations.

"Returnable? If the orbits are the same, there shouldn't be much point in returning, right?" said the comrade working on the satellite.

Gao Zhendong shook his head: "The requirements for the communication system of the recoverable satellite are not that high, which can save weight. At the same time, the requirements for the power supply are not that high, which can also save weight. Although it costs the film, it can still save a lot of launch weight overall. If this launch weight is put on the optical system, the resolution can be higher. Before our optical system is developed to a certain level, recoverable satellites are still unique in special circumstances. And..."

Hearing that a higher resolution could be achieved, the leader of the Defense Work Committee nodded in agreement: "Well, that's true. We can't be biased. What do you mean by 'and'?"

Gao Zhendong's eyes lit up. "Besides, it doesn't matter whether the recoverable satellite is actually for photo reconnaissance or something else. The most important thing is that it 'returns'! And our recoverable satellite technology comes from an exchange with the Russians. Don't forget what that recoverable satellite was originally."

The Russians' recoverable satellites at this time were relatively large in size and weight. The reason was actually quite simple. Their recoverable satellite was actually an improved, unmanned "Vostok" spacecraft!
When the comrades heard his words, they all remembered this incident.

The leader of the Defense Work Committee also had a gleam in his eyes: "Zhendong, you mean... people?"

Gao Zhendong nodded: "Yes, we may not need to send people up there for now, but it is always good to use recoverable satellites and the Russians' technology to prepare first. Maybe we will need it someday."

This matter may not be urgent, but it must be prepared.

"And if scientific experiment payloads are to be carried, the demand for recoverable satellites will be even stronger. After all, scientific experiments are not only about transmitting test data back, but also about obtaining test samples."

The leader of the Defense Work Committee and the chief engineer looked at each other and said, "Well, you have a point. We can spend money to launch a manned spacecraft for the sake of face, but for scientific experiments, as long as there is a need, we can still launch one or more return satellites."

It doesn't matter if it's just about face. After all, the first place in this matter is gone. There's no need to develop a manned spacecraft for the time being without demand. In this regard, Gao Zhendong is not even worried that someone will come to snatch the first place in Asia. A manned spacecraft is not a satellite. It is impossible that the Japanese in the previous life could steal the title of "Asia's first satellite" by shooting a few kilograms of iron into the sky. In fact, the Japanese had never shot a manned spacecraft in the previous life until Gao Zhendong traveled through time.

Did they not want to? Of course not. After all, the Japanese wanted to be better than others in everything. Moreover, they were not short of money. If they were not short of money, they were short of technology.

In this regard, even if the Japanese want to turn "manned space flight" into "slaughtering space flight", they can't do it, after all, they still have to have some face.

South Peninsula: It’s better not to have this thing.

But scientific experiments are really useful. Returning to the experimental module and returning for photographic reconnaissance can be done without spending money on manned missions, because there are no requirements for life support and the safety requirements are not that high or extreme.

"But what we just mentioned are either not urgently needed or have to wait. Apart from these, what is the most urgent thing now?" said the leader of the Defense Work Committee.

"The most urgent thing, of course, is the communication satellite that is not very useful." Gao Zhendong laughed.

"Yes, yes, yes, the original purpose of inviting the comrades working on satellites here was for this matter." After talking for a long time, he completely forgot about this matter.

The comrade working on the satellite smiled and said, "This is not a big problem. In fact, since this thing does not have a camera system, the communication requirements are relatively low. We can make the satellite smaller and directly put it in a 700-kilometer sun-synchronous orbit. Chief Engineer Gao just said that although this orbit is not very suitable for communication, it is relatively better. The specific time of revisiting is fixed, which is more convenient for users." After all, one is to transmit pictures and the other is to transmit messages, and the communication requirements are different. With the foundation of the previous satellite, this satellite itself was actually very fast to build.

The leader of the Defense Work Committee frowned when he heard this: "The time is too fixed, it's easy to be caught. Let's fire more missiles. You must plan the track well, at least the pattern can't be so obvious."

The time is too fixed. Once others react, even if they can't catch them, they will turn on high-power interference at a fixed time and place, which is not a good thing. Even if it can't be staggered, you have to prepare more time periods for sending and receiving. After all, it is not a pleasant thing to adjust the orbit frequently in space. Let's not talk about whether it can be adjusted or not. With the current body of the satellite, it can't be adjusted many times.

The satellite comrades realized that these satellites were quite interesting and that such requests were rare. But they were smart and did not ask any more questions: "Okay, we understand."

Although this type of "communication satellite" has many restrictions on use, it is a feasible option under current conditions.

This kind of situation often occurs in research. Sometimes it is said that "XX solution cannot achieve YYY function". In fact, it is only when there are better options or there are severe limitations in some aspects that it is judged as not feasible from multiple angles such as cost, complexity, usage conditions, and lifespan.

If you really need it and are forced to do so, you can still use a defective one and it can still be used for a long time.

In this regard, Citigroup’s “Zeizhi Satellite Navigation” and our “Beidou-1 Navigation” are typical examples.

The former is Citigroup's first generation global satellite positioning system, which is not well known to the general public. Its positioning accuracy is 50 meters, which sounds good, but it cannot provide continuous real-time positioning, and the interval between two positionings can be as short as 35 to 100 minutes, or as long as 10 hours. It is barely adequate for use by the navy and the army, and can only be said to be OK for use by aircraft. Citigroup used this kind of stuff until 1996 when it was completely discontinued.

The same is true for our BeiDou-100. The positioning principle of BeiDou- is very interesting. It takes a long time to explain it in detail, but in short, it has two major defects. First, it is active positioning. If you want to locate, you can't keep radio silence. Second, although it can locate continuously, it can't achieve high-speed movement positioning by itself. And when there is no calibration station, the positioning accuracy is only meters. It is also a defective system. We also use BeiDou- network.

The same is true for the current "communication satellite". In terms of its usage, it is similar to Citigroup's Transit Satellite Positioning System. It provides functions when the satellite comes, and has to wait when the satellite flies away.

But it's just this thing, you decide whether you want to use it or not. If you evaluate it from a general perspective, this thing is not usable, but for current needs, this system is still good. The question of "whether it is available or not" is often the first priority.

However, Gao Zhendong decided to start working on solving this problem. Not to say that he would solve it immediately, but at least he couldn't delay it for too long.

"I think we still need to work hard on the geostationary orbit. The characteristics of this orbit are very obvious and have high application value." Gao Zhendong put forward his first idea.

Geostationary orbit, also known as geosynchronous orbit.

This is a bit professional. The leader of the Defense Work Committee looked at the comrades working on satellites, meaning, come on, explain it.

"The geostationary orbit can fix the satellite in place above a certain point, and it provides conditions for many applications. For example, the geostationary orbit is very suitable, but this orbit has high requirements." Without leaving any trace, the comrades working on satellites not only explained this orbit, but also raised their own concerns.

"How high are the requirements?" The leader of the Defense Work Committee understood what he meant. So this orbit is more suitable for communication satellites? However, he did not have any extra thoughts about Gao Zhendong not proposing to use the geostationary orbit for the current communication satellite. Since Comrade Zhendong knew this orbit, he must have his reasons for not choosing it. He just wanted to know what the advantages and disadvantages of this orbit were.

"The biggest problem is that it's too high!" How high is the requirement? Very high, just like the track itself is also high.

"Too high?"

"Yes, the orbit is about 36000 kilometers high. We can't send a satellite into this orbit now. At least, we can't get there until a high-thrust launch vehicle is developed."

my country's first geostationary orbit satellite is Dongfanghong-84. It sounds like it was launched right after Dongfanghong- and should have been very close in time, but in fact, this satellite was launched in using Yuanzheng-.

"In this regard, I can tell you openly that our comrades are developing a three-stage liquid carrier rocket." The chief engineer of the Defense Work Committee interjected.

The main function of this three-stage liquid carrier rocket is space flight, and it is also a backup for solid intercontinental ballistic missiles. This was decided a few years ago, and Gao Zhendong's suggestion played a very important role at the time.

"We have had contact with this, but according to the planned rocket capacity, it is not very high, and we cannot launch something particularly heavy into geostationary orbit. And this distance places extremely high demands on the communication system, so the total weight of the system cannot be reduced, which creates a contradiction with the orbit's carrying capacity." said a comrade who works on satellites.

The problem of insufficient transportation capacity actually has various sources, including satellites, rockets, and even launch sites.

As a casual player who had played Kerbal Space Program briefly, Gao Zhendong knew a little bit about it: "What is the orbit you are planning?"

The issue of orbit is related to both the rocket and the satellite itself. Since the comrades working on satellites said that the carrying capacity is insufficient, it is highly likely that they and the comrades working on rockets discussed the orbit and made calculations using a fictitious satellite plan.

It is known that Gao Zhendong's words are not groundless, and he has some understanding of satellite orbits. Although he may not have reached professional level, he has achievements in other professional fields. Combining these knowledge, there may be some improvement.

Therefore, comrades working on satellites can speak without reservation. There is nothing to hold back here. Naturally, someone will stop people from saying anything that should not be said. Chief Engineer Gao himself has enjoyed this treatment many times.

"First hit the geostationary transfer orbit, then perform a Hohmann transfer, and finally enter the geostationary orbit." This sounds a bit difficult to understand, but Gao Zhendong understood it.

Simply put, the geostationary transfer orbit (GTO) is an elliptical orbit with a large eccentricity, a perigee of only a few hundred kilometers and an apogee of up to 36000 kilometers. The satellite enters the orbit at the perigee, and then maneuvers again at the apogee, which is exactly the height of the geostationary orbit, to enter the geostationary orbit (GEO).

Compared with directly hitting GEO, this method has a higher capacity while achieving the same orbital altitude.

"Do you carry out the Hohmann transfer once or multiple times?"

After hearing Gao Zhendong's words, the comrades working on satellites realized that they had underestimated Comrade Gao Zhendong. His familiarity with orbits was definitely not just superficial!
"The simulated onboard engine thrust was insufficient and was executed multiple times."

This is a blessing in disguise, as it can save some fuel.

"The rocket launch site or the current satellite launch center?"

"Yes, we only have this one launch site." The comrade who works on satellites said with a wry smile. In fact, it is precisely because of the location of this launch site that the carrying capacity has been reduced.

"What is the exact apogee of the transfer orbit?" The apogee and perigee of different transfer orbits are different, and it is precisely this difference that can be used to play some tricks, and that's what the Russians do.

"The apogee is roughly the geostationary orbit, about 36000 kilometers."

Gao Zhendong laughed.

(End of this chapter)