Siheyuan: I eat melons while doing scientific research

Chapter 1231 SSTO (4k, 5k more)

Hey, comrade, why are you still laughing? The satellite was a little depressed.

Seeing the smile on Gao Zhendong’s face, the comrades in the Defense Work Committee who were familiar with him knew that this smile was not a mocking one, but a smile of joy.

This often indicates that he should have some way to solve or improve the problem to a certain extent.

Don't underestimate improvement. Some problems cannot be completely solved. For example, insufficient firepower can only be improved but not solved.

Often, just a small improvement can turn a technology or equipment from unusable to usable. For example, in the case of solar panels for satellites, Gao Zhendong only "improved" the efficiency to more than 20%, and that's all.

"Tell me, what are your ideas? We don't understand, but they do." The leader said with a smile.

Gao Zhendong nodded: "It's nothing, actually. To launch a satellite from this base, the two most important things are to raise the orbit and raise the perigee to 36,000, and to reduce the inclination, right?"

The Russians are at a disadvantage here. The geostationary orbit is above the equator and has an orbital inclination of 0. All of their launch sites are at high latitudes, and removing the inclination may not sound like a big deal, but it actually consumes a lot of fuel.

We are a little better than them. We even have an island in the Tropic of Cancer - Tianya Island. However, we are not considering setting up a space launch site there now. One of the main reasons is transportation issue.

But the Russians were pushed into a corner, so they still had a lot of tricks. The method Gao Zhendong was going to talk about was exactly what they came up with. After all, among the major powers, their latitude is the highest. Apart from us and the Americans, the Gauls have very good conditions. The latitude of their launch site in South America is very low, just over 5 degrees, which saves a lot of money.

As for the shame of the five good men - John Bull...

Let's put it this way. Before 2020, this country never had its own proper launch site, or in other words, they had never even launched their own proper rockets. They just used the European Space Agency to brag that they had certain space capabilities. For a place that relies on the charity of the Citigroup for its intercontinental missiles, it's a bit ridiculous to say how strong its own space capabilities are.

"Yes, Chief Engineer Gao, can you find a way to increase the transportation capacity on the track?" If that's the case, that would be awesome.

Gao Zhendong shook his head: "I can't increase the transport capacity, that is a theoretical limitation, but we have a way to save the fuel you consume during the entire process of entering the GEO orbit."

The specific impulse, Δv, and so on are theoretically the same.

The first half of the sentence made the comrades feel disappointed, but the second half made them feel happy again.

By saving fuel, the carrying capacity of fuel can be used to carry mission payloads, thus increasing the carrying capacity in disguise. Alternatively, the same amount of fuel can be loaded, but the life of the satellite can be greatly extended.

As I said, in terms of satellite lifespan, the durability of components and power supply are not big problems. The biggest problem is that the fuel used to maintain the orbit has been burned out, or to be more precise, the working fluid has been sprayed out.

After all, some engines don't necessarily need to be burned. In fact, it's OK to bring a helium bottle to spray, as long as it doesn't leak like the Starline of the Citigroup. Of course, there are more advanced products, but it's a bit early now.

"Really? Is there any way?" The comrades working on the satellite were so excited that tears were about to come out.

Gao Zhendong said: "Greatly increase the apogee of the transfer orbit! Descend from a higher orbit to the geostationary orbit!"

This is SSTO, Super Synchronous Transfer to GEO.

This answer directly confused the comrades who were working on the satellite. I don’t have enough fuel here, and you want to launch it to a higher orbit and then bring it down. It’s like taking off your pants to fart, and this fart is even more laborious.

But they knew very well that since comrades at Gao Zhendong's level spoke so confidently, there must be some way.

As for the leaders of the Defense Work Committee, they were even less clear about these things. They just watched Gao Zhendong show off quietly. They had confidence in Gao Zhendong's level.

"Chief Engineer Gao, to be honest, we are a little confused. Can you explain it to us? Theoretically, it consumes more fuel to reach a higher orbit." They couldn't turn this corner no matter what.

Gao Zhendong stood up and drew a track diagram on the blackboard, explaining as he drew.

"You're right. We can reach a higher orbit, which we call a super-synchronous transfer orbit (SSTO). Note that SSTO here does not have fixed parameters. It is a general term for a type of orbit. It does require more fuel to reach SSTO, but we have to consider the problem together. We also have to eliminate the orbital inclination. If we look at these two things together, the situation will be different."

As he spoke, the comrades working on the satellite began to understand a little.

"You mean, the de-tilting step on the SSTO?"

Gao Zhendong nodded: "Yes, this operation will be more complicated. Basically, after entering GTO, we will further raise the apogee to enter SSTO, and then try to eliminate the inclination at the apogee of SSTO, and then raise the perigee to 36,000 of the synchronous orbit, and then lower the apogee of the orbit to 36,000 of the synchronous orbit. At this step, we have entered the Earth orbit, and we can eliminate the remaining inclination and enter orbit completely!"

This whole process is much more complicated than the original GTO to GEO, but the comrades who work on satellites listened to it with great interest.

"…The reason why we need to eliminate the inclination at the apogee is, in fact, to use a vivid analogy. When we close a door, the farther our hand is from the door axis, the smaller the force required for the same closing torque. The same is true here. The smaller the Δv required, the less fuel is needed. I have calculated that for our latitude, the fuel saved here is more than the fuel consumed by sending the satellite into SSTO. The savings are greater than the consumption. When you calculate everything, it saves fuel!"

At the same time, Gao Zhendong also roughly calculated on the blackboard the same capacity demand, the fuel required and the fuel saved for the SSTO de-inclination that he often used in his previous life, and compared it with the extra fuel paid for increasing the capacity demand to SSTO.

It can be said that it is well illustrated with both text and pictures, and the theory is detailed.

After Gao Zhendong's explanation, the comrades understood.

"That's a great idea! I never thought of taking latitude and inclination into account."

"Yes, if we launch a satellite near the equator, then the SSTO may not have much benefit. But at high latitudes like ours, the SSTO can theoretically save a lot of fuel."

"Yes, a satellite doesn't need much fuel to maintain its orbit. The fuel saved can extend the life of the satellite by years. Many years!"

"Our biggest headache is life expectancy."

“……”Looking at the performance of their comrades, the comrades of the Defense Working Committee knew that Gao Zhendong’s method was really useful, and that it was not too difficult to understand or apply. It was considered a typical "Gao method."

Gao Zhendong knocked on the blackboard: "Also, this plan has another advantage."

And the upside? Comrades feel like things are too good to be true.

"You are using a three-stage rocket, the second stage enters the transfer orbit, and the upper stage enters the synchronous orbit, right?" The upper stage here refers to the last stage closely connected to the satellite, which is the third stage on a three-stage rocket.

"Correct!"

"Have you ever considered that this might actually cause a waste of fuel in the second-stage rocket? For satellites of different weights, the second-stage rocket sometimes does not need to burn all of it, or does not need to carry so much fuel?"

"Yes, there is such a problem. If we use a GTO orbit with fixed parameters, the fuel usage of the second stage must be adjusted as the weight of the satellite changes. In fact, there is a possibility that the fuel will not be used up. What you mean is..."

Seeing that they had understood, Gao Zhendong nodded: "Yes, so, here, we can directly use up all the fuel of the second-stage rocket, and use the second-stage rocket to directly send the upper stage and satellite into SSTO. To some extent, it is waste utilization."

Satellite comrades, look at me and I look at you, this is brilliant!!! This can squeeze out the potential of the first and second stages, and actually save more fuel for satellites that are not at their capacity limit!

But the joy didn't last for a second. Someone reacted and raised his hand: "Chief Engineer Gao, there is a problem here. Satellites of different weights can reach different SSTO orbit altitudes. It's different every time. For some satellites, the second stage may not even be able to put the upper stage and satellite into the required SSTO altitude."

In that case, each launch will require more complex orbit planning. This is fine, and it does not pose a problem for comrades. The key is that satellites at the limit of their capacity are not even high enough to be launched that high.

Gao Zhendong nodded: "Yes! So, here we will encounter a stumbling block for this method - multiple ignitions of the rocket engine!"

"Multiple ignitions? What are they used for?"

"When used on the upper stage, when the upper stage is heading for SSTO, it takes on the task of relaying the second stage to ensure that the upper stage and the satellite reach the required SSTO orbital altitude. The upper stage also takes on tasks such as eliminating the inclination later, so multiple ignitions are required. Of course, some orbital operations can be completed by the satellite itself after the upper stage separates, but at least a second ignition is necessary."

Whether the complex orbit change operation is completed by the upper stage or the satellite itself is determined based on actual conditions. The upper stage may not need so many ignitions, but at least a second ignition is inevitable.

"As for the secondary ignition, I think those comrades working on rockets should not have any problem. Besides, the upper stage is a small engine among several general-purpose liquid engines, so it is relatively easier to handle." said the comrade working on satellites.

The Defense Work Committee also nodded repeatedly. If you want to gain benefits, you have to pay a price, and the price is not too high.

Gao Zhendong is not too worried. A few decades later, there may be some problems with the secondary ignition of our low-temperature fuel engines, but the secondary ignition of room-temperature fuel engines was broken through very early, so there will be no problem. If we focus on tackling the problem under the current conditions, there will not be any major problems.

"That's fine. In this way, the fuel saved is equivalent to increasing the transportation capacity in disguise." Gao Zhendong said with a smile.

The comrades also laughed, from the bottom of their hearts, because they had never thought of this. When the comrades brought back this orbital plan, the comrades who were developing the rocket were so happy.

The Defense Working Committee looked at the clock. Apart from the tightly covered ventilation windows, this conference room didn't even have windows, so the sky couldn't be seen. Most of the day had passed in the meeting with Gao Zhendong making suggestions and explanations, and the comrades hadn't even had lunch yet.

To those comrades working on satellites, this is no big deal and they have no time to even eat.

"Comrades, it's almost time. Let's eat first. The body is the capital of revolution. Man is made of iron and rice is made of steel. If you don't eat, you will feel hungry. As for the remaining things, we will deal with them in the last minute of this afternoon." It can be said that in the view of the Defense Work Committee, the most core issues have been resolved. What remains is the question of what the synchronous satellite will be used for. There is enough time to discuss it in the second half of the afternoon.

We can’t let these babies here starve.

The comrades then closed their notebooks reluctantly, followed suit, and went to eat.

As the comrades were moving forward, the leader of the Defense Work Committee stopped Gao Zhendong.

"Zhendong, I want to ask you something." It seemed that he was left behind and wanted to ask Gao Zhendong something. But it was probably not a big deal, otherwise he wouldn't have stopped him at the last minute.

"You say."

"Well... do you have any idea to increase the survival rate of trees planted in the desert?" The leader of the Desertification Committee probably thought this was outrageous, so he spoke hesitantly.

Hmm? Gao Zhendong is really screwed.

"No, leader, you shouldn't ask me about this, right? Comrades from the Forestry University are much more professional than me." The two talked as they walked, and other comrades consciously kept a distance from them.

The leader of the Defense Work Committee smiled bitterly and said, "That's what happened..."

The whole story is actually related to the recent arrival of the Kolka sandstorm. After all, compared to the deserts in our three northern regions at this time, the Kolka desert is nothing.

In this matter, Kolka itself is nothing. What really attracts attention is the sandstorm. After all, this thing can also be generated in China, and it may be even more severe than over there.

The issue of sand prevention and control has attracted great attention, and we have always liked to carry out pilot projects when doing things.

And this pilot area was chosen in those places that cannot be clearly stated.

The reason is very simple. At present, there are only a few places in the desert Gobi with enough people to launch pilot projects quickly and on a large scale. Moreover, these pilot sand control projects can also improve the living environment there, which can be regarded as killing two birds with one stone.

In this way, money was saved and progress was guaranteed, but a new problem arose: the source of planting technology was narrow and development was a bit slow. Because those places could not mention it at all, and they could not discuss it with ordinary forestry personnel.

There is no problem with the overall technology. All you have to do is specify the environment type, select the tree species, and develop a plan. However, some of the detailed issues encountered in the process are difficult to consult.

(End of this chapter)