The military-industrial scientific research system of the academic master.

Chapter 1260 The rocket's orbital accuracy is the missile's hit accuracy

It should be said that the basic Dongfeng 31 cannot be considered a ballistic missile with outstanding performance.

If classified according to the 8000-kilometer threshold of the early years, it can only barely touch the edge of intercontinental missiles.

Fortunately, the difficulty of this mission lies mainly in the flying net organization. Even the satellite that performs the interception mission is disposable and will fall into the atmosphere and burn up along with the captured space debris.

Therefore, the requirements for the platform are not high, and the expected launch payload is only around 100kg.

As long as the energy management of the active phase of the rocket is done well, successfully entering orbit is not a difficult task.

At the same time, because the launch vehicle can be used for cold launch directly on hardened ground that meets certain requirements, it does not need to occupy a valuable satellite launch station, which is undoubtedly great news for the launch system that is close to saturation at this stage.

Although China started relatively early in the aerospace field, it has long been constrained by its national strength and has invested limited resources in this area.

Take the manned space program as an example. From the launch of the project in early 92 to the end of the first phase, the total budget for more than ten years was only in the order of tens of billions of RMB.

Under such circumstances, it is already a miracle that the engineering and technical personnel can ensure the project progress and launch success rate through meticulous work. As for the issue of "quantity", it naturally has to be considered secondary.

The fewer launches, the less experience you gain.

Due to lack of experience, in order to ensure the success rate, it takes longer and more detailed preparation.

Therefore, at this stage, the space launch cycles at China's three major launch sites are quite long.

For example, launching seven times in the second half of 2004 was already an "overclocking" level that broke the limit and was worthy of a special article to celebrate.

During the peak of the Cold War, the crazy frequency of launch missions by the United States and the Soviet Union every few days seemed almost like a science fiction movie to the Chinese at that time.

In fact, China itself did not have much demand for satellite launches, and the contradiction between its launch capabilities was not too obvious.

To be honest, it was Chang Haonan himself who, after entering the new century, strongly promoted China's development in the field of aerospace applications through the two projects, Ocean No. 1 and Qingluan Constellation, and greatly increased the demand for the number of satellites in orbit.

To some extent, it is a case of being trapped in one's own trap.

In short, after Chang Haonan wrote this idea into a report and submitted it, it was approved almost without a doubt.

And Yin Liangxing, general manager of China Aerospace Science and Industry Corporation, was personally responsible for connecting with him.

Different from the model of many state-owned enterprises where the top leader is in charge of management and the second-in-command is responsible for specific business, General Manager Yin Liangxing is a real professional.

Until more than two years ago, he was still in charge of specific front-line research and development work.

He should have a lot in common with Chang Haonan.

Sure enough, after meeting, the two of them just exchanged a few simple greetings and then quickly got down to business.

"According to the information provided by our partners, we expect a relatively strong solar storm in September and October this fall, which will disrupt many spacecraft in orbit and may also cause certain changes in orbital parameters."

Chang Haonan directly took out the solar activity detection report provided by the European Space Agency through the Star Company:

"Considering that the orbital altitude of this piece of space debris is not much different from that of the International Space Station, if it is further affected and causes its orbit to drop, it may really threaten the safety of the space station. Therefore, we hope that the launch and capture mission can be completed within the time window of late August to early September."

Yin Liangxing watched with great interest at first, but then he became confused:

"Wait a minute... Although solar activity can indeed affect the orbital parameters of a spacecraft, I read relevant information before I came here. The debris is still several kilometers away from the space station... It's unlikely that a solar storm would cause such a large drop, right?"

The business of China Aerospace Science and Industry Corporation is mainly missiles, but he is an old engineer who has been working in the aerospace system long before the separation, so he has some understanding of these things.

"The actual possibility is indeed not great..."

Chang Haonan nodded and replied:

"The main mechanism by which solar storms affect orbits is that they induce Joule heating and particle precipitation, which increases the density of the Earth's upper atmosphere, causing a significant increase in the resistance to satellites in orbit. However, this peak period only lasts 2-3 days."

"That……"

Yin Liangxing obviously wanted to ask something else, but when he noticed that Chang Haonan seemed not to have finished speaking, he kept silent and waited for further explanation.

"In the past two to three days, the orbital changes of low-orbit spacecraft are very exaggerated. Without power boost, it is likely to drop 200-300 meters every day."

The latter continued:

"This is a golden window of opportunity for us. We can take advantage of it to exaggerate the urgent threat of space debris to the outside world and unilaterally announce that NASA's rescue plan has failed. Then, before the solar activity completely ends, we will solve the crisis. In this way, we can naturally play the role of a savior... You know, Westerners often fall for this."

Poor Comrade Yin had just switched from a technical position to a full-time administrative position a year and a half ago, and he was managing a relatively autistic company like China Aerospace Science and Industry Corporation. When he heard Chang Haonan's sinister plan, he was instantly shocked.

Fortunately, he had seen many storms and soon recovered from his surprise:

"If this is the case, then the requirements for launch cycle and mission flexibility are indeed very high..."

During the time when Chang Haonan was explaining the situation, the technical staff from China Aerospace Science and Industry Corporation had already taken out some of the electronic data they had brought with them.

So Yin Liangxing changed the subject and began to introduce his own situation:

"The production of the basic DF-31 has basically entered the final stage. Currently, it is at the lowest production pace, mainly to preserve the production line and wait for the next improved model to go into production. Therefore, production capacity and working hours are not a problem."

"However, the thrust of solid rockets is highly nonlinear, and their flexibility is much lower than that of liquid rocket engines. In addition, the launch sites in southern my country close to the equator have been relatively sparsely tested in the past, so the requirements for energy management and orbital entry design are higher."

Although it is not uncommon to convert a ballistic missile into a launch vehicle, the missions they perform have their own characteristics. It is definitely not the case that you can just remove the warhead and replace it with a satellite.

The more critical issue is.

China has not even tested solid rockets, let alone medium- and long-range solid missiles.

In fact, Yin Liangxing attached so much importance to this mission. In addition to the fact that the order came directly from the top leadership, another important factor was that he hoped to accumulate more working data of solid rocket engines, which in turn would help the next generation of intercontinental ballistic missiles, which were in the critical stage of research and development...

"Don't worry about the orbital entry strategy."

Chang Haonan waved his hand:

"Comrade Zhou Pingjian, the chief designer of the manned space program, and Comrade Xing Muchun, the former deputy chief designer of the Long March 2F carrier rocket, are both in charge of the space fishing boat program. They are quite experienced in this area and have enough time to plan a new launch mission."

"As for the energy management issue..."

He directly handed the other party a page that he had already written in his notebook:

"Since the control sequence of a single sub-stage engine is fixed for solid-propellant launch vehicles, the basic function is to use a gliding method to increase the orbital altitude during the active phase of the orbital insertion process. Based on the transfer orbit planning data of fixed-point guidance, I can develop a set of flight trajectory algorithms for the rocket boost phase."

However, Yin Liangxing shook his head:

"That's not the point..."

As he continued to explain, he took a piece of paper from the side and drew a picture:

"Liquid-fuel rockets can adjust the flow and speed of fuel through valves during propulsion, so essentially they do not perform specific actions at a specific time, but after reaching a certain position. However, the engine operating time of solid-fuel rockets cannot be freely controlled. Once started, they can only be shut down once at a preset time point."

"Even for some solid thrusters that have segmented propulsion capabilities, partitions are added to specific locations of the solid grain, and the on/off time cannot be freely controlled. Therefore, some additional actions are required at the middle and end of the solid thruster operation to consume the excess speed increment. This process of dissipating the excess speed will affect the position component of the rocket and the final orbital accuracy."

Having said this, Yin Liangxing paused for a moment, then changed his tone to one of regret:

"On the other hand, the circular error probability of the basic DF-21 and DF-31 is not ideal. In addition to the accuracy problem of the inertial navigation system itself, there is also the factor that the energy management of the solid rocket engine is relatively rough."

"Including the Type 31A missile, which is currently in the final stages of development, the focus is only on increasing the range and truly reaching the threshold of intercontinental missiles. As for further reducing the circular error probability and realizing multiple independently targetable reentry vehicles, these are still the goals of the next generation of models..."

"..."

"Although the satellite that performs the space fishing boat mission is not large in size, it has a certain degree of maneuverability and orbit change capability, so it is not demanding in terms of orbital accuracy..."

Chang Haonan first dispelled the other party's concerns from the perspective of task requirements.

But he could also hear that the other party came here with a purpose and expectation, and would definitely not be satisfied with simply bypassing the problem.

So he continued:

"Of course, the circular probability... uh... if the orbital insertion accuracy can be improved, that would be the best, but this is a specific technical issue... I have to get the relevant design data of Dongfeng 31 before I can give you a clear answer."

As expected, Yin Liangxing was overjoyed:

"Regarding this, Academician Chang, you can rest assured that we will fully cooperate with your work!"