The new 110-ton liquid oxygen kerosene engine has been tested on the test bench dozens of times in the past six months, with a combined duration of more than 10,000 seconds.
Multiple rounds of tests were conducted on the operating status of the new liquid oxygen kerosene engine under various working conditions, and detailed data on the engine in different conditions such as ground environment and high altitude environment were obtained.
The high-altitude environment and the ground environment have a relatively large impact on the engine. The low gravity, thin atmosphere and low temperature at high altitude have a certain impact on the operation of the engine.
This is because the rocket engine has its own oxidizer. If it were an aircraft engine that uses air as the combustion oxidizer, it would be useless in a high-altitude environment.
In the past six months, the test run time of a single engine has increased from more than 400 seconds to more than 1,000 seconds.
Because the new liquid oxygen kerosene engine will most likely be used on the first batch of recyclable rockets that will be tested for flight next year, the service life of the engine is directly related to the number of times the rocket is used.
Every extension of the service life of the rocket engine basically means that the cost of using the recyclable rocket will be reduced.
Only when the cost of using recyclable rockets is low enough can Zhang Xingyang be confident in persuading his superiors to carry out the seemingly exaggerated low-orbit satellite communication network plan.
After all, according to Zhang Xingyang's description, the number of satellites in the entire plan has almost reached more than 50,000, which is unbelievable for people of this era, and the number that needs to be replaced every year has reached about 20,000.
Even the thrust of the newly developed rocket developed by the Rocket Research Institute is large enough, and it can launch hundreds of low-orbit communication satellites every time it is launched.
This still requires more than five hundred rockets, and the cost of the rockets alone is in the billions, close to tens of billions.
This is only the cost of building this satellite communication network, not counting the subsequent annual maintenance costs.
Annual maintenance requires the launch of more than 20,000 satellites. If a traditional one-time rocket solution is adopted, more than 200 rockets will be needed. Even though domestic prices are not very high at this time, labor and material costs are very low, and the cost is close to Three to four billion.
If you want to know how much the annual military expenditure is, it is less than 50 billion in total.
This will be divided between the army, navy and air force, and the Second Artillery Force (later the Rocket Force) as a strategic deterrent.
And if the rocket recycling strategy is adopted, even if the first batch of rockets cannot achieve the theoretical ten recycling times due to technical problems and are only reused three or four times, close to 60% can be saved. of rocket cost.
In other words, the construction cost of the entire system can be reduced from the original tens of billions to three to four billion, and the subsequent maintenance costs are only about two billion per year.
And this is only the cost of completing the entire low-orbit satellite communication network.
According to Zhang Xingyang's idea, within the first two years, basically only the domestic communication network can be completed.
If the domestic communication network is to be successfully constructed, only 4,000 low-orbit satellites are needed to complete the basic construction.
Moreover, these 4,000 satellites can still be completed in phases. According to Zhang Xingyang's plan, the first phase of the construction project can be completed with only 1,000 satellites.
After all, what everyone needs most at this time is not the high-speed Internet access function like in later generations. For many people who have never even touched a mobile phone in their lives, the voice call function is the highlight.
The amount of data transmission occupied by the voice call function is completely incomparable with the Internet function.
Because the first few rockets will not directly use second-hand, third-hand or even ninth-hand rockets, the cost will be slightly higher.
But this is also necessary because the first few launches must test the performance of the rocket to a certain extent.
In order to catch up with the first experimental launch of the recyclable rocket in 1997, people in various systems are working hard to keep up with the progress.
The most critical and difficult part of the entire system is the propulsion system of the first-stage rocket.
The first-stage rocket propulsion system using eleven YF-110 liquid oxygen and kerosene engines is basically a monster level of difficulty in the eyes of rocket engineers in this era.
You know, no one in China has ever made such a complex propulsion system before.
Because this rocket has only a two-stage structure, the requirements for the first-stage rocket, which is the main source of propulsion, are extremely high. In the past, three-stage rocket systems were commonly used in China.
Compared with the two-stage rocket structure, the three-stage rocket system has stronger redundancy capabilities and can more conveniently adjust the attitude of the rocket during flight.
However, the overall structure of the three-stage rocket will be relatively more complex, but the propulsion system of each stage will be simpler. After all, each stage needs to be propelled to a lower height.
Especially for the rockets commonly used at this time, there have never been so many rocket engines in each stage.
Take the Changsanyi rocket that was launched not long ago as an example. Its first-stage rocket uses four YF-31C liquid rocket engines.
Although four boosters using YF-25 rocket engines are used at the same time, it is actually less difficult because of the bundled form.
After all, when the Changsanyi rocket was launched, the four YF-21C liquid engines and four boosters of the first-stage rocket were ignited at the same time.
As for the eleven rocket engines of the newly developed recyclable rocket, because the recovery function must be taken into consideration, some of the rocket engines must be turned on during recovery to allow the first-stage rocket to decelerate and land.
This requires that the eleven engines of the new recyclable rocket can be controlled separately and ignited in stages.
This puts forward higher requirements for the design difficulty of the entire first-stage rocket propulsion system. Compared with previous rocket design difficulties, one seems to be climbing Mount Tai, while the other is climbing Mount Everest.
It is precisely because of this that Zhang Xingyang arranged this linkage test of multiple rocket engines to test the mutual influence of the engines when they operate separately.
The number of engine linkages tested has been increased from two to eleven in order to gradually explore the influence between them.
This is also to prepare for the future launch of various models with different thrust sizes and different orbital carrying capabilities.
After all, it is impossible to use a high-thrust rocket every time. Sometimes, some commercial launch missions also require some small-thrust, low-cost rockets.
For example, there are only four YF-110 liquid rocket engines used as a small-thrust rocket in the first-stage rocket propulsion system. The total cost is only about 5 million, which is very suitable for carrying out commercial launch missions of some small satellites.
