Comprehension

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I plan to write a book recently to systematically summarize and sort out the books I have read and the problems I have thought about in the field of manned deep space exploration in recent years. On the one hand, this textbook can be left to graduate students who take my course, on the other hand, it can also help me clear my mind, try to make a precise breakthrough after finding the right problem, and make myself more professional and in-depth. Because I wanted to write a book of the same type, I unconsciously picked up Qian Lao's Introduction to Interstellar Navigation and read it again. When I was reading Qian Lao's book, I just joined the work. It has been 20 years, but I have a different feeling after reading it again. .....

Introduction to Interstellar Navigation is compiled according to the syllabus and handouts of Introduction to Rocket Technology taught by Mr. Qian Xuesen at CUHK 1962. In the preface, Mr. Qian Xuesen wrote: writing this book aims at two purposes: one is to explain various technical problems in the realization of interstellar navigation, so that on the one hand, scientific and technological workers who are committed to these single problems can understand the significance of each problem in all their work; On the other hand, it is also necessary to explain the high comprehensiveness of interstellar navigation technology, which includes almost all the latest achievements of modern science and technology, such as modern mechanics, atomic energy, special materials, high-energy fuels, radio electronics, computing technology, automatic control theory, precision machinery, aerospace medicine and so on. The further development of interstellar travel not only puts forward new and higher requirements for the above-mentioned science and technology, but also puts forward research topics for botany, zoology, biophysics, ecology, genetics, geology and other disciplines that have not been linked so far, giving these disciplines unprecedented impetus.

The second purpose is the complexity and arduousness of interstellar navigation practice. Every department of interstellar navigation needs a huge organization of research, design, experiment, manufacture, launch and communication, and a team of tens of millions of scientists, designers, engineers, technicians and workers. These departments need the highest quality and quantity of equipment to carry out their work; Therefore, it is impossible to imagine the all-round development of interstellar navigation without a strong and complete industry in all aspects and a multi-disciplinary and large-scale scientific and technological team. Naturally, interstellar navigation technology is not mysterious, it is only the concrete application of general natural laws. The foundation of interstellar navigation technology is also well-known basic disciplines, such as mathematics, physics and chemistry. What we want to emphasize is that it is not mysterious but not simple. Interstellar navigation is a concentrated expression of the highest level of modern science and technology, and it is not easy.

The two purposes described by Qian Lao in his preface reveal exactly two problems: First, interstellar travel is a scientific issue, including all aspects of modern science and technology. I am surprised that Qian Lao mentioned the possible application and development of space medicine, geology, genetics and ecology in interstellar travel in 1962. We didn't realize this problem until 20 12 wrote the book "Manned Moon Base Project". Secondly, interstellar travel is a space engineering technology. There is no doubt that the cause of interstellar travel cannot be separated from basic space vehicles such as rockets and spaceships. My 20-year working experience in the industrial sector tells me that the construction of these aerospace products is not mysterious, but it is not simple, not to mention the specific technical scheme design details, and there are countless requirements for quality control and product guarantee alone. In order to integrate the individual product systems of each subsystem, Qian Lao proposed to set up the overall design department, which is responsible for the overall design of the system. Therefore, it is no exaggeration to say that interstellar travel is a combination of space science and aerospace engineering technology. It's amazing that Qian Lao was able to reach such a strategic height when giving lectures to students at 1962.

Qian Lao's first chapter is about the basis of interstellar travel and space travel, including Chiolkovsky formula, interstellar travel, acle formula and so on. Acle formula points out that when traveling to other stellar systems at superluminal speed, it must be calculated on the basis of relativistic mechanics, and the differences between acle formula and Tsiolkovsky formula are compared. Qian Lao also pointed out that to realize Centauri, we must rely on ultra-high energy nuclear fuel. As for the general situation of astronomical stars and galaxies, I should have started to contact them in 15, more than half a century later than Qian Lao. ......

The second chapter of Qian Lao talks about the principle and technical realization of rocket engine, including solid propellant, liquid propellant, extrusion engine and pump engine in liquid engine, as well as the design of combustion chamber test, transportation regulation system test, engine test run and test bench. In the design of solid motor, the grain design, grain technology and combustion stability are discussed. What surprised me most was that Qian Lao also mentioned the solid-liquid engine and the method of adjusting the thrust direction of the engine. For example, a solid motor can't adjust the thrust by the method of a liquid motor, but a part of high-pressure gas can be led from the combustion chamber to the collision part of symmetrically arranged nozzles, and the jet direction can be changed by an oblique shock wave. Because there is no air rudder and servo mechanism, this method should be a relatively light design. At this point, I am not sure if there is any better idea to change the thrust vector design of today's solid motor.

The fourth chapter of Qian Lao talks about the technical realization of launch vehicle, including the series of multi-stage rockets, structural weight, structural ratio, structural weight composition, the relationship between structural weight and ignition weight, the design process of launch vehicle, the layout of launch site and system composition. It is hard to imagine that China didn't have these things at that time. How does money always master these basic and core methods from the design of Saturn V rocket in the United States? These basic theoretical methods are the basis and source for guiding the design of China Long March rocket.

The fifth and sixth chapters of Qian Lao are about the launch orbit and interplanetary navigation orbit of the launch vehicle. In the launch orbit of the rocket, the orbit of the lunar rocket is actually considered, while in the interplanetary navigation orbit, the orbit with small thrust is unexpectedly changed and the star is forced to fly. What's even more amazing is that the light sail is also considered. Think about what I introduced last year in his "Breakthrough Shooting Stars" project about Hawking's micro-nano spacecraft going to Centauri. It is the sail of the sun, which uses the principle of solar light pressure to realize interstellar navigation. It's hard to imagine what it was like when Qian Lao taught his students to sail more than half a century ago.

The seventh chapter of Qian Lao is the most admirable chapter. He teaches atomic rocket engines, which is what we now call nuclear-powered rockets. Even more amazing, he also talked about the design principle of electric propulsion rocket and the more forward-looking deuterium rocket engine. I vaguely remember that this year someone publicized a major breakthrough in electric propulsion technology, so when can we wait for nuclear-powered rockets and electric rockets?

The eighth chapter of Qian Lao talks about guidance, including the iterative guidance of launch vehicles and the guidance accuracy of interstellar travel to Mars orbit. For initial guidance, intermediate guidance and terminal guidance, the design of guidance system, product composition and environmental test are all mentioned.

Chapter 9 of Qian Lao talks about communication problems in interstellar travel, including communication delay, antenna power, noise, information rate, communication equipment and ground receiving antenna, and light wave communication. And I am still blank in this respect.

Chapter 10 of Qian Lao is about re-entry into the atmosphere, including re-entry trajectory, blunt body orbit and lift orbit of manned spacecraft, thermal protection design of spacecraft re-entry, hyperbolic orbit re-entry when going to Mars, and deceleration descent to the surface of Mars by using the atmosphere of Mars. In the last paragraph, Qian Lao proposed to create a magnetic field in the spacecraft head with an electromagnetic coil, and use the interaction between magnetic lines and conductive gas to push the hot gas of plasma away from the spacecraft head. This new way of releasing heat can not only pass through the atmosphere safely, but also reduce the requirement of propellant dosage, thus improving the effect of interstellar navigation. What I want to say is that a few years ago, it seems that someone came to me to promote his innovative conceptual design. At that time, the man seemed very proud of his innovative ideas. It turns out that this is something that Qian Lao pondered half a century ago. Unfortunately, this heat protection scheme has not been realized so far.

Chapter 11 of Qian Lao talks about radiation protection, including photon's effect on matter, electron's effect on matter, neutron's effect on matter, radiation's effect on human body, radiation dose, cosmic rays, solar flares, neutron's protection, and radiation's destructive effect on electronic components. Think about it. Did our major in space environment and radiation protection run out of this circle today?

Chapter 12 of Qian Lao is about the design of spacecraft, including the influence of weightlessness and overweight on people, the design requirements of spacecraft cockpit, the living conditions of people during interstellar travel, the supply of oxygen and water, and even the ecosystem of interstellar spacecraft during long-distance travel, as well as the problems of preventing micrometeorite and crossing the asteroid belt, and the orientation system of spacecraft.

Chapter 13 of Qian Lao talks about the power supply of spacecraft, including the use of chemical energy, sunlight, atomic energy, radioactive substances, chemical batteries and solar photovoltaic cells, as well as turbine generators, thermocouple generators, thermionic generators and electromagnetic fluid generators. So far, I still don't understand these problems.

Chapter 14 of Qian Lao talked about several problems about the further development of interstellar navigation, including the satellite interstellar space station, which is now called the space station; It also includes the launch of launch vehicles at sea, the recovery of launch vehicles, and the use of aircraft as vehicles, which is what we call air-launched launch vehicles today. Look at today's China Aerospace. How much have we accomplished?

After reading Qian Lao's Introduction to Interstellar Navigation, I felt a lot. I have read many articles about the achievements and future development prospects of China's space industry. Does anyone really compare these individual technologies with the lectures given to students by Qian Xuesen at 1962? Look at the interstellar navigation framework proposed by Qian Lao, and how much real innovation and progress we have. He who has no foresight must have foresight. Although I am a grass-roots person, I also advocate a pragmatic style of study. Interstellar navigation is a profession with both science and engineering technology. Where can there be any impetuous spirit?

After all, a master is a master. As the pioneering work of China's space industry, the book is comprehensive in content, clear in formula derivation process and admirable in professional depth. What kind of books are my idols and goals? First of all, I recommend Qian Xuesen's Introduction to Interstellar Navigation, which is forward-looking and professional and can stand the test of history, peers and practice! A well-deserved pioneering work! At the same time, the text in the book is easy to understand, which is easier for readers to accept and learn than some advanced doctoral theses.

Unfortunately, it's hard for me to write a masterpiece like a master, and I can't control all aspects of space technology like a master, but I can make some problems in the field of manned deep space exploration deeper and more detailed, and I can also study more forward-looking problems and ideas. When I founded this ship for interstellar voyage more than a year ago, I was impressed by Qian Lao's profound skill and stole my name. Reading Qian Lao's works after 20 years is more about understanding and respect. I sincerely suggest that readers read this book carefully and make up for the shortcomings by comparing themselves. I also hope that the book published by our team one year later will have some real value and contribute a little to China's space industry!