Compared with offensive laser cannons, defensive laser cannons have much smaller power, mass and volume. The overall structure of a laser cannon is similar to a telescope, with an external tube and precision optical devices inside. The diameter of a precision laser cannon can reach up to 10 centimeters, and its length can reach several meters. However, the maximum diameter of a defense laser cannon is only centimeters, and its length is only about 30 centimeters. Its expertise is also completely different from offensive laser cannons. The divergence angle of the attacking laser cannon is extremely small, so it can attack targets that are relatively far away. The divergence angle of the defensive laser cannon is not very demanding because the targets are usually close, having already passed through the defensive electromagnetic cannon defense circle and are only tens of kilometers or even hundreds of meters away from the spacecraft. Its maximum attack range is only a few hundred kilometers. Beyond this distance, it will lose its lethality due to the divergence of the light beam. It also has low power and low lethality. After all, its targets are just tiny projectiles, so it doesn't really need to be that big. Compared to its poor performance in other aspects, its activation time and duration are far higher than that of offensive laser cannons. It doesn't even need charging preparation time, and can be started instantly. At the same time, because the overall power is low and there is no need for too much heat dissipation, it can be used for a long time, up to several hours, which is much more efficient than the offensive laser cannon that starts for dozens of seconds and then rests for dozens of seconds. This is also customized based on its tactical needs.
After all, in the interstellar battlefield, the number of electromagnetic cannon projectiles may be extremely large, and there are a large number of interception targets that need it to intercept. If the start-up speed is too slow, the high-speed electromagnetic cannon projectile may hit the hull before it starts. If the duration is too short, how can we stop the electromagnetic cannon projectiles everywhere? Taking all the requirements into consideration, the offensive laser cannon and the defensive laser cannon have completely different shapes and performances. After a long period of continuous iteration and research, the defensive laser cannon has now been initially perfected and has practical significance. Therefore, Li Qingsong has mastered all four weapons: offensive electromagnetic cannon, defensive electromagnetic cannon, offensive laser cannon, and defensive laser cannon. In addition, the high-speed radar has undergone three rounds of optimization, and its reliability and stability have been greatly improved, while its size and weight have been greatly reduced. It seems that Li Qingsong has all the requirements for building a truly "modern" warship. But Li Qingsong knew that it was not enough. There was one crucial component missing. High-speed bogies. In the interstellar battlefield, both offensive and defensive weapons have extremely high requirements for accuracy and reaction speed. It is possible that a spaceship passes in front of our side at high speed, and the time window for attack is only a few tenths of a second or even a few milliseconds. It is also possible that a projectile suddenly appears and flies towards you at high speed, and the interception window is only a few milliseconds. Radar has detected it and defensive weapons have the ability to hit it, so what else is missing? Aiming accuracy and reaction speed. The muzzle of an offensive or defensive weapon must complete the corresponding turn in a very short time, from aiming in other directions to aiming at the target, and then fire immediately. The reaction speed must be extremely fast, and the steering must be done immediately upon discovery. The steering accuracy must be extremely high, and the slightest deviation will make it impossible to hit the target. For a projectile that is 50 kilometers away from our side - this distance is already extremely close for interstellar battlefields and the flight speed of projectiles - for every ten-thousandth of a degree difference in the aiming angle of our defensive electromagnetic cannon or defensive laser cannon, after 50 kilometers, the error will expand to about centimeters. The size of an electromagnetic cannon projectile, even a heavy electromagnetic cannon projectile with a mass of 5 grams, is usually no larger than 1 cm. An error of cm is a huge difference.
After a simple calculation, Li Qingsong confirmed that in order to accurately aim at a target 50 kilometers away, the accuracy of the electromagnetic cannon or laser cannon must reach one hundred thousandth of a degree. It can be confirmed that in an interstellar battlefield, laser cannons and electromagnetic cannons must be in motion at all times, and must constantly change their aiming positions, possibly changing their directions dozens of times in a second. The spacecraft may be in a state of violent maneuvering, transfer, vibration or shaking at all times. In this case, the muzzle moves dozens of times per second, and the accuracy of each movement must be as high as one hundred thousandth of a degree. This requires extremely high accuracy and speed. Even Li Qingsong is not sure he can do it now. This technology has also been under development for decades. At the beginning, Li Qingsong used the most advanced materials and the most sophisticated equipment he could find, but he could only move the muzzle once per second with an accuracy of one hundredth of a degree, and that was while he was completely stationary. This performance is actually high enough, but it is still far from the actual combat requirements. Li Qingsong could only mobilize a large amount of manpower, material resources, energy and brainpower to carry out continuous iterative research on this technology, just like he did with several other key technologies. After spending a long time and raising his technical level to the limit, Li Qingsong could only improve the accuracy by about a hundred times, which still did not meet the requirements of actual combat. After reviewing the entire research process, Li Qingsong finally determined that there was only one way to break through the existing accuracy limit. Develop tougher, less abrasive materials and once again advance metalworking technology. There is nothing much to say about improving metal processing technology, it is nothing more than a matter of grinding. But the development of new materials is full of uncertainties. After working on materials research for so long, Li Qingsong increasingly feels that there is no essential difference between developing new materials and what ancient humans called alchemy. Throwing some inexplicable things into the alchemy furnace, only God knows what will be produced in the end. The same is true for materials research. Using a variety of raw materials, going through a variety of processing methods, heating, freezing, stirring, standing, chemical treatment, etc., etc., what kind of material will be produced in the end and what kind of properties it will have, only God knows. Existing theories of chemistry, physics and materials science are still too backward, and it is impossible to develop suitable materials through theoretical calculations alone. In that case... I have no choice but to use my ultimate move. Following the rough guidance at the theoretical level, Li Qingsong directly set up 500,000 material research teams, with two clones in each team. Each team tried a new formula and directly adopted a brute force approach to carry out this materials research.