Chapter Two Thousand Three Hundred and Sixty Seven Arrows Falling from the Sky (Part 2)
Just when everyone was staring at the big screen, the image of the secondary rocket surveillance camera in the window suddenly froze.
At this time, Yu Chengwu explained aloud at the right time: "The rocket has entered the black barrier area, and the communication is temporarily interrupted. Next, the rocket itself will be controlled."
While Yu Chengwu was talking, the window on the big screen had switched to the observation screen of the ground optical infrared telemetry equipment. In fact, it was a bright spot with a faint tail. This was because the rocket descended at high speed and rubbed against the dense atmosphere, causing
The insulating material of the secondary rocket body is evaporated by heat, which is captured by the infrared thermal imaging equipment and displayed on the screen.
In the eyes of ordinary people, this is just a bright spot with a small tail, nothing special. But in the eyes of professionals, this bright spot contains a lot of information. They can judge the descending glide state of the rocket based on the changes in this bright spot.
During the normal descent of the second-stage rocket, this bright spot is flying with a faint tail. If there is a problem, such as the rocket insulation material failing, causing friction and burning of the rocket body, then this bright spot will be brighter, and the rocket will be dragged behind.
The tail will also be brighter and longer.
If this bright spot suddenly appears and flashes by, it means that an object on the rocket body may have fallen off during the rapid descent and friction with the atmosphere.
If this bright spot flashes, it means that the flight attitude of the entire rocket is out of control. The rocket is not sliding downward smoothly, but is in a rolling state. Only in this state will the bright spot flicker.
If this bright spot suddenly explodes and separates several bright spots with long tails, it means that the rocket body may not be able to withstand the stress intensity generated by such a high-speed descent and friction with the air, causing the entire rocket body to directly stair in the air.
Any of the above phenomena will cause the entire second-stage rocket return and landing experiment to fail. This is why this technology is so difficult and no one has completed it yet.
And this is not just a purely technical issue, but a matter of technical and economic benefits.
Spacecraft that simply re-enter the atmosphere from space, or return-type spacecraft, and return-type satellite technology have been mastered by many countries and companies. It has only one purpose, which is to safely return the spacecraft or satellite to the earth from space.
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You don’t need to think too much about cost. The material is naturally strong and strong, and there are no requirements that are too sensitive to weight.
The technical difficulty of the two-stage rocket is how to combine technology with economic benefits and find the best balance point.
As we all know, in order to be able to transport heavier loads, the launch vehicle itself is very light, and the entire rocket body structure is very light. The purpose is to save its own weight, so that it can transport heavier and more movements.
Ninety percent of the weight of a launch vehicle is fuel, and only 10% is the weight of the launch vehicle itself. As for reusable launch vehicles, because they need to be reused many times, the rocket body
The structure, including the structure of the engine, has been strengthened, which has also increased its own weight, making its carrying capacity possibly not as large as a disposable rocket of the same level.
However, relying on the advantage of being reusable, this rocket can significantly reduce the delivery cost.
Of the cost of a commercial launch vehicle, only about 2% to 5% is the fuel cost, and 95% is the price cost of the rocket itself. In other words, for a rocket worth 100 million, the fuel cost
The price is only 5 million, while the cost of the rocket itself is 95 million.
Although the manufacturing cost of reusable rockets is higher than that of disposable rockets, they can be reused, which saves the cost of the rocket itself. All it incurs is fuel costs and recovery and maintenance costs.
It is thought that such a reusable rocket can win orders at a price far lower than the commercial launch price in the industry. The cost can be recovered after two launches, and the rest will basically make money. However, a rocket like this, or a first-stage rocket, has less
It is said that it can be used six or seven times, or even a dozen times at most.
This shows how lucrative such a reusable rocket can be. Of course, commercial insurance is generally purchased during commercial launches to prevent the worst results. After all, no one can guarantee that every launch will be foolproof.
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The insurance company will also evaluate and quote based on the status of your rocket. Maybe the more times you rocket, the higher the policy quote from the insurance company will be, so this will also be factored into the cost.
Compared with the core first-stage rocket, the core two-stage rocket is more sensitive to the weight of the rocket body. A little more weight will reduce part of the carrying capacity. Therefore, the project technology research and development team must save the weight of the second-stage rocket as much as possible.
But there is a premise, that is, the strength of the second-stage rocket must be up to standard, especially during the take-off phase, it must withstand huge gravity acceleration, and it must also withstand huge air resistance and friction during the landing phase.
In the current world, the strength and weight of any material are directly proportional. In other words, the heavier the weight of the material, the higher the strength. The smaller the weight, the smaller the strength. No one can change this.
So this is a contradiction, and a major goal of the technology research and development team is to find a balance point between the two, that is, to use the lightest material to achieve the maximum rocket body strength.
Although there will be a certain degree of redundancy between the design parameters and the actual environment, that is to say, the strength of the rocket itself is higher than the stress it will be subjected to in reality to ensure that the rocket body can withstand a harsher environment than reality.
However, in actual operations, there are too many uncertain factors, and a small change may cause the entire task to fail. This is very common in reality.
To give a simple example, the earth's low orbit is currently filled with a large amount of tiny particles of garbage. Many of these are natural celestial bodies, meteorites, meteorites, etc., while some are artificial garbage and debris from some spacecrafts.
These debris are burned up in the Earth's orbit as they orbit and fall into the atmosphere at high speeds. The rocket needs to pass through low-altitude orbit and the atmosphere, which also means that it may collide with these orbiting and falling debris.
Unlike other spacecrafts that have such anti-collision designs, the launch vehicle does not have an anti-collision layer in order to ensure its absolute lightness. A fragment may penetrate the integrated rocket body.
The so-called "thousand-mile journey" is destroyed in an ant nest. It is possible that a single damage or trauma can cause the entire rocket to disintegrate during its rapid descent.