With the rapid development of space technology, people have more and more opportunities to explore space, but the main challenges of space flight continue to hinder our dream of flying further. People.
1. Ion Repulsion Technology
Traditional rockets can be launched by having a high-speed exhaust at the back. Ion repulsion also applies the same principle of repulsion, but it does not use combustion fuel to generate intense heat, but rather a series of charged particles or ions that are released. It's possible that its thrust is relatively weak, but the important thing is that the ion propellant needs much less fuel than a conventional rocket. As long as the propulsion feature can remain stable for a long time, it will eventually be able to accelerate the spacecraft at a higher speed.
Ion propulsion related technology has been applied to a number of spacecraft in space, such as the Japanese space probe " Hayabusa " and the spaceship " SMART-1 "", moreover, the technology has made great progress. Farther in the future, the most promising spacecraft in outer space tourism is probably the VASIMR ion rocket. This type of rocket. is slightly different from normal repulsive ions.Common repulsive ions use a strong electromagnetic field to accelerate ionic bodies, while ionic rockets like VASIMR use radio frequency generators that heat up ions as hot as 1 million degrees Celsius. In a strong magnetic field, the ions rotate at a fixed frequency, tune the radio frequency generator to this frequency, inject powerful energy into the ions, and continuously increase the repulsion. preliminary proves, if all goes well, the ion rocket VASIMR will be able to send a manned spacecraft to Mars within 39 days.
2. Nuclear impulse propulsion technology
Feasibility: very achievable, but extremely dangerous
Among the types of technology, in common sense, the most dangerous and most reckless must be said to be nuclear impulse propulsion technology. The basic idea of nuclear impulse propulsion is that the tail of the rocket periodically throws out an atomic bomb to create thrust. This bizarre idea was put forward by the Department of Defense Advanced Research Planning Agency of the US Department of Defense. This research project was called " Plan Orion ", which was actually considered by the US in 1955. The goal of the plan was to study a program of fast interstellar travel. In the program finally launched by the Agency for Advanced Defense Research Planning, the booster was designed as a "shock absorber".” large, moreover there is a radiation shield to protect the safety of passengers.
The program seems possible, but it could pose a radioactive hazard to the atmosphere. Therefore, in the 60s of the 20th century, this plan actually finally did not come to fruition. Despite these concerns, some are continuing to work on nuclear impulse propulsion. In theory, the speed of nuclear-powered spacecraft could reach 10% of the speed of light. At this rate, reaching the nearest star could take 40 years.
3. Nuclear fusion missile
Feasibility: Possible, but at least after decades.
The technology of space flight based on nuclear propulsion completely not only has nuclear impulse propulsion technology, but also has other methods of using nuclear energy. For example, rockets are fitted with a fission reactor to generate jet fusion, which in turn generates thrust.
In nuclear fusion reactions, the nuclei are compressed fusion thereby producing enormous energy. Most fusion reactors use tokamax which controls the fuel in a magnetic field to regulate fusion. But, tokamak is very heavy, completely unsuitable for rockets. Therefore, fusion-engine rockets must inevitably adopt another method of inducing fusion, namely inertia-limited fusion. This design uses a high-energy beam (usually a laser) to replace the tokamak's magnetic field. As the fusion reactions occur, the magnetic field continues to guide the spray ions into the rocket's tail, creating the thrust of the fusion nuclear engine rocket.
4. Busade . jet engine
Feasibility: There is a huge technological challenge.
All boosters, including thermonuclear ones, present a similar key conundrum. In order to achieve the target faster and farther, the rocket must carry more fuel, and more fuel inevitably increases the weight of the rocket, which in turn reduces the thrust. If you want to travel among the stars, you definitely have to stay away from that situation. So, in 1960, physicist Robert Busade proposed a jet engine, and the Busade jet engine could solve this problem.
The principle of the Busade jet engine is the same as that of a nuclear fusion missile, but it does not need to carry enough nuclear fuel at all. Its working principle is: First, ionize hydrogen substances in the surrounding space, then use a strong magnetic field to absorb hydrogen ions as fuel. While the Busade jet engine program did not have the reactor problems found in nuclear fusion rockets, the problem it faced was the issue of magnetic field levels. Since there is very little hydrogen matter in interstellar space, its magnetic field must be wide enough for this to be possible, even extending to thousands of kilometers. Unless it is carried out detailed calculations before launch, designing the precise trajectory of spacecraft flights, so it will not need to carry a lot of fuel, no need for big magnetic field anymore. However, this idea has the disadvantage that the spacecraft must be operated according to the established orbit, cannot fly to the outside, and the return journey from another planet will become more difficult.
5. Solar powered propulsion technology
Feasibility: is completely feasible, but adapts to limited space.
This is a technology that needs to carry enough fuel, so it can theoretically reach very high speeds, but it often takes a while to achieve this goal. Compared to the traditional use of wind power to drive boats, the solar " grid " will draw energy from the sun's rays. Currently, solar propulsion technology has been successfully tested in a vacuum chamber on earth.
However, conducting experiments in space has not been successful. For example, in 2005, the American Planetary Society - the world's largest amateur space science organization researched and built a spaceship " Universe 1 ", a rocket carrying a " grid " of the sun. its crashed due to an accident.
Although there are many problems in the early stages of the technology, the solar " grid " is still a very promising future space technology. At least it can guarantee flights in the solar system, sunlight can give it the most thrust. In the future, humans will be able to mainly use solar energy for interstellar travel.
6. Magnetic net push technology
Feasibility: suitable only for close space flights, as in the solar system.
The difference with the solar grid is that the magnetic field is pushed by the solar wind, not by the sun's rays. The solar wind is a stream of charged particles with a magnetic field. Scientists propose, around the spacecraft to create a magnetic field that opposes the solar wind's magnetic field, so that it will be possible to use the convection force of the magnetic field to propel the spacecraft through space. A similar technology also has the " space spider " technology , which creates an electric grid around the spacecraft, which can push large amounts of positive ions in the solar wind, thereby gaining thrust.
Whether it's a magnetic net, or a " space spider " technology , it must use a magnetic field to " surf ".", the magnetic force makes the spacecraft can change orbit, even leave interplanetary space. Solar nets or nets from the wall are not suitable for traveling between planets. When as they move away from the sun, the intensity of the sun's rays and the solar wind both rapidly decrease, so it doesn't have enough thrust to travel to another planet.
7. Laser propulsion technology
Feasibility: There are also major technical challenges.
Because the sun is not enough to propel the spacecraft, scientists have come up with laser propulsion technology, the use of extremely large laser beams that will propel the spacecraft into space, that technology is the "burning out" technology. laser" . The so-called " laser burn " is the use of extremely powerful lasers to erode the special metal of the spacecraft's stern, the metal gradually evaporates and creates thrust.
Một loại công nghệ tương tự khác đó là công nghệ lưới mặt trời do nhà vật lý và tiểu thuyết khoa học viễn tưởng Gregory Benford đưa ra, tức là lắp đặt lưới mặt trời vào tàu vũ trụ. Trên lưới mặt trời có phủ một lớp sơn đặc biệt. Phát ra một chùm vi sóng trên mặt đất, chùm vi sóng này đốt cháy lớp sơn đặc biệt sinh ra các phân tử tạo nên lực đẩy. Công nghệ này có lẽ sẽ làm cho việc đi du lịch giữa các hành tinh trở nên nhanh hơn.
Laser propulsion technology also presents significant challenges. First, the lasers must be focused on the spacecraft precisely, even though the distance is longer, the laser beam can't have any errors. Otherwise, the spacecraft will crash due to insufficient power. Second, the power generated by the lasers must be super strong. In some cases, the energy required for it can be much higher than all present human energy.
8. Space-time variation technology
Feasibility: not very likely.
In 1994, University of Wales physicist Miguer Aerkubilie proposed the technology to use interplanetary matter. In this idea, the propulsion of the spacecraft is mainly provided by " extraterrestrial " matter (which has not been discovered at present). This is a nut with quality and back pressure. It can " distort " time and space, thereby making the spacecraft rapidly approach the space ahead, while the space behind is constantly expanding. The spacecraft is like being in a balloon that is getting bigger and bigger and can fly faster than the speed of light, moreover it will not go against the principle of relativity.
However, the technology idea of Aerkubilie has many problems. First, to sustain this variation of time and space, a very large amount of energy is required, which can be larger than the entire energy of the universe. Second, this machine can release a large amount of radiation, which seriously threatens the life and safety of spacecraft passengers. In addition, whether "extraterrestrial matter" exists or not has not been determined so far. So, physically, it is very difficult to create this variant bubble.
9. Technology using black holes
Feasibility: completely unlikely.
Because some people have thought of space-time variation, there are scientists who have thought " space-time tunnel ". They believe that it is possible to use " wormhole " (wormhole, black hole) to realize this idea. The concept of a " wormhole " proposed by the famous American physicist John Wiley Harrell, means that in the universe there can exist two consecutive narrow tunnels of different space-time. The main question here is, does " wormhole " really exist? If yes, can we get through? However, these questions have not yet been answered. Possibly similar to " extraterrestrial " matter as above, " wormholes " do not exist at all.
In the 90s of the 20th century, physicist S. Kafelnikov also proposed another concept of " wormhole ". However, all " wormhole " theories cannot provide definitive proof of the existence of " wormholes ", much less can suggest any realistic plans for traveling through space-time. . If scientists can find the answer, then the speed of spacecraft will be more than just the concept of the speed of light.
10. Multi-dimensional space technology
Feasibility: is very confusing.
We can often see space as usually three-dimensional. However, German physicist Wilhelm Bernhard Buck thinks that, if the universe had more dimensions, then spacecraft could pass through them and achieve great speeds.
The super-fast spacecraft can fly to the moon in minutes, to Mars in just 2.5 hours, to reach the Alpha Centauri galaxy in just 80 days. However, this idea was difficult to understand, Wilhelm's theory was never accepted by his colleagues.