Chu Tianjiang noticed that the nuclear warhead that Zhang Xiaogang called "Crazy Ivan" was not large.

The shape of the three nuclear warheads resembled a rugby ball magnified by more than ten times, in the form of an irregular elliptical sphere, except that the surface made of metal was very smooth. Except for a thin slit in the middle that looked like an interface, there was not a single gap or opening.

"It's just a titanium casing, and the nuclear warhead is inside."

"So small?"

"How big do you think it should be?" Zhang Xiaogang smiled and said, "As early as ten years ago, the United States was able to create a megaton nuclear warhead weighing no more than 80 kilograms. It's just that the explosion principle of 'Crazy Ivan' is different from that of a hydrogen bomb, otherwise it can be made smaller. ”

"What's the difference?"

Zhang Xiaogang didn't have an axe, so he left the opportunity to explain to the scientific researchers.

"Theoretically, the explosive yield of a hydrogen bomb can be infinite. All stars in the universe are hydrogen bombs, and they burn in exactly the same way as hydrogen bombs explode, converting matter into energy through nuclear fusion. However, in reality, it is impossible to achieve an infinite explosive yield of hydrogen bombs, because we do not have the means to generate high temperatures and pressures inside stars, and we cannot provide a physical environment for continuous nuclear fusion. Ordinary hydrogen bombs actually use the atomic bomb as a fuse to trigger nuclear fusion with the high temperature and high pressure generated when the atomic bomb is exploded. Even so, it is not possible to allow hydrogen to carry out fusion reactions, so most of the fusion raw materials used in hydrogen bombs are heavy hydrogen and super heavy hydrogen, that is, deuterium and tritium. The isotopes of these two isotopes of hydrogen are gases under normal conditions, and in order to increase the density of fusion raw materials, ordinary hydrogen bombs are generally filled with deuterium and tritium lithiide. After the explosion of the atomic bomb, the core temperature and pressure will drop sharply, and the physical environment for fusion can only last for tens of milliseconds, so when the hydrogen bomb explodes, only a very small part of the concentrated heavy hydrogen and super heavy hydrogen will be used. ”

"What does it matter?"

"A larger explosive yield means that more heavy hydrogen and super heavy hydrogen are needed for fusion reactions, which in turn requires a larger atomic bomb to sustain the physical environment in which fusion can be achieved for a longer period of time. The problem is that the yield of an atomic bomb cannot be infinite, and even a reinforced atomic bomb has a yield of less than 200,000 tons. ”

"That is, limiting the yield of the hydrogen bomb."

The scientific researcher nodded and said: "With the traditional method, the yield of the hydrogen bomb can be up to 100 million tons, and the largest nuclear test in history is only 50 million tons. ”

"Then how did you make such a 200-million-ton nuclear warhead?"

"The use of fusion materials with higher densities increases the number of fusion materials in the ignition zone, that is, in the area where the temperature and pressure are sufficient for fusion reactions, so as to increase the explosion power to 200 million tons without prolonging the ignition time."

"This ......"

"This is a very ingenious method, and it was Luo Jinyong who came up with it." Zhang Xiaogang made the following explanation for the scientific researchers. "Deuterium and tritium are used in metallic form. In this way, not only can the explosive yield be increased, but the utilization rate of fusion raw materials can be increased to about 50 percent, thereby greatly reducing the mass of the nuclear warhead and enabling it to reach extremely high speeds with the means available to us. ”

"How much does this guy weigh?"

"Counting the shell, less than a hundred kilograms."

"So light!?"

"Eighty-seven kilograms, with a positive and negative error of 0.5 kilograms." Scientists have a clear answer.

"In addition, the method that Luo Jinyong came up with has greater significance."

"What's the point?"

"Even with the most advanced technology, deuterium and tritium in their metallic form can only be stored for six months. According to the calculation of 50 percent redundancy, the value of super-nuclear warheads is only three months. That is, after production, if it is not used within three months, the super-nuclear warhead will turn into an atomic bomb with a yield of 20,000 tons. By controlling the production of metallic deuterium and tritium, the possibility of any country retaining super-nuclear warheads for a long time can be eliminated. Of course, this also allows us to start assembling super-nuclear warheads only three months after the last three months. ”

Chu Tianjiang nodded, indicating that he understood the meaning of Zhang Xiaogang's words.

There is an essential difference between a 200-million-ton super-nuclear warhead and a 20,000-ton atomic bomb. The former is capable of destroying a medium-sized country with a land area of about one million square kilometers and is a weapon of destruction. The latter can only destroy a medium-sized city with a population of about 200,000, which can be considered a weapon of mass destruction at best.

"Still have questions?"

"I want to know what is the final speed of 'Crazy Ivan' when launched with the 'Divine Arrow'?" In Diego Garcia, Chu Tianjiang learned from Luo Jinyong about something related to Operation Courage, so the speed of the super nuclear warhead was crucial when it came to intercepting the target.

"Make full use of the earth's gravitational acceleration to reach 200 kilometers per second, otherwise it will not exceed 180 kilometers per second."

"Isn't that a little slower?" Chu Tianjiang knew that the 2014X1 asteroid had exceeded the speed of one thousandth of a light, and the objects ejected when decelerating would definitely be faster.

"This is also the reason why the interceptor is launched into low-earth orbit with a super-nuclear warhead, and then launched by a carrier rocket at the incoming object. If launched from low-earth orbit with a total mass of 500 tons, the launch vehicle will be able to accelerate a super-nuclear warhead to more than 400 kilometers per second. According to the adjusted interception scheme, the total mass of the launch vehicle has been increased by 50%, and two rocket engines have been added, which can accelerate the super-nuclear warhead to 600 kilometers per second. Zhang Xiaogang sighed and said, "It's a pity that we can only launch from the ground." The super nuclear warhead launched by the 'magic arrow' cannot take the object out of the impact trajectory, but can only change the impact point. ”

"How much can it change?"

"The relationship with the interception distance is basically linear, and it is also related to the mass of the object. If the mass of the object is 100,000 tons, the offset is about one hundredth of the interception distance. If the mass of the object is a million tons, it is only one thousandth. Of course, the premise is that the interception distance should not be too close, at least not less than 100,000 kilometers, otherwise the impact of the curvature of the earth's surface will greatly reduce the offset. ”

Chu Tianjiang thought for a while and said, "In this way, the 'Divine Arrow' must be launched in advance, otherwise it will be impossible to intercept the incoming object at a long enough distance." ”

"Lao Chu, you have the potential to become a scientist."

The scientist smiled and said, "That's true, when Judgment Day comes, we have to launch synchronously, otherwise we will miss the opportunity to intercept." That's why we installed an orbital offset engine on the load, which reduced the maximum speed we could achieve by about ten percent. ”

"Because we weren't fast enough, we couldn't make the first move."

Chu Tianjiang nodded, indicating that he understood what Zhang Xiaogang meant.

If the magic arrow can make Crazy Ivan reach a fast enough speed, Zhang Xiaogang will definitely suggest to strike first and let a 100,000-ton object fall on the mainland of the United States.

"Fortunately, there is no intelligence to suggest that the United States has similar defensive weapons."

"This ......"

"To put it simply, when we perform, the Yankees can only watch the excitement. As long as we can successfully intercept the objects flying towards our mainland and the surrounding areas, we can save the day, and there is no need to worry that the Yankees will use the same method to make our efforts useless. ”

"Russia also has this thing, right?"

"Yes, there are as many as us, but according to the information I have received, Russia has only completed the assembly of three rockets and three nuclear warheads, and the fourth set will definitely not be completed in time." Zhang Xiaogang smiled and said, "In addition, it is still unknown whether the magic arrow and the crazy Ivan can be used. ”

"What do you mean?"

"The speed of the asteroid is very fast, and if it starts to slow down at a distance of 20 million kilometers, the ejected object will arrive in fifteen hours. The interception starts at 1.2 million kilometers away and ends at a million kilometers, with an interception time of only nine minutes. If we happen to turn our backs to the 2014X1 asteroid, that is, the United States happens to face the 2014X1 asteroid, then no matter what tricks the Yankees play, it is not us who are unlucky. ”

Chu Tianjiang thought about it and understood this truth.

"Alright, let's go see the computer simulation test."

The three left the nuclear warhead warehouse and went to the first central hall. In accordance with Zhang Xiaogang's instructions, the scientific researchers used computers to simulate the entire interception process.

It can be said that the Shenjian launch vehicle was designed with great attention to secrecy.

For example, the payload takes 10 minutes to enter low-Earth orbit, which happens to be the time it takes to launch a super-nuclear warhead deployed in low-Earth orbit. At this critical moment, the attention of all countries in the world is focused on the launch of low-earth orbit, and the probability of discovering the magic arrow rocket has been greatly reduced. If the Tiangong space station is controlled, the first three stages of the Divine Arrow rocket can be plunged into the atmosphere at the same time as the launch vehicle on the space station. As a result, Mad Ivan, launched by the Divine Arrow rocket, will follow the other super-nuclear warheads towards the incoming object. Although Crazy Ivan is much slower, the interception window is only nine minutes, and by the time other countries discover Crazy Ivan, the interception operation will be over.

Without exception, these confidentiality considerations are all aimed at increasing the probability of interception.

After having a comprehensive understanding of the Houyi project, Zhang Xiaogang took Chu Tianjiang to taste the homely food in the base. Before leaving, Zhang Xiaogang also brought these letters from some scientific researchers. The scientific research center implements a completely closed management, and it is difficult for researchers to contact their families.

The letters were not sealed so that they could be checked by the security agencies.

Scientific researchers and technical workers have a high consciousness, and through hard work and self-sacrifice, they fight for the right to survival and development for mankind and the Chinese nation!