What challenges will space technology face in the future?

After forty or fifty years of development, space technology has entered the stage of comprehensive benefits. At present, the application of satellites is constantly improving and expanding the scope of application; Military satellites are constantly upgrading; Astronomical satellites and interstellar probes constantly send back new information about the universe; Manned space flight is being carried out in an orderly manner; Space shuttles and spaceships often travel between heaven and earth; The international "Alpha" space station has been built ... In the more distant future, what direction will space technology develop and what challenges will it face in the future?

No matter what choice is made, the development of space technology must be based on solving the problems faced by mankind, benefiting mankind and enhancing human knowledge and wealth. At present, mankind is facing countless problems, which are becoming more and more serious with the development of industrialization. Since the space age, people have put forward various methods to solve the above problems. Some of them may be the direction of future space development.

Population, ecology and environment are hot issues in the world today. 1969, American physicist O 'Neill put forward the idea of space city and space immigration. He believes that the best way to solve the above problems is to build space cities in space and gradually move humans to space cities around the earth. Space City has a natural environment suitable for plant growth, with herbs, trees, rivers and lakes. In addition to these artificial natural environments, the space city also has roads, residential areas, entertainment areas, commercial areas, work areas and so on. After human beings moved into space, the earth has been transformed according to the role of natural forces for a long time to restore its vitality and good ecological environment. Hundreds of years later, the earth will go into battle without human intervention, and become more vibrant, with animals in groups, trees in shade, good weather, sunny weather and renewed Vientiane. If necessary, man can return to the earth.

With the expansion of the concept of space migration, many ideas of establishing a lunar base and even transforming Mars appeared in 1970s and 1980s. Scientists from the National Aeronautics and Space Administration put forward this idea on July 8th, 199 1. They made a rough timetable for the process of transforming Mars: after initial exploration, by 20 14, the human advance team will take the lead in landing on Mars. They first conducted an investigation and initially opened up the equatorial region. 15 years, 10000 experts landed on mars. They installed solar reflectors, built nuclear chemical plants and built nuclear power plants to calcine Martian ores and rocks. These efforts are aimed at producing a large amount of carbon dioxide, creating an artificial greenhouse effect and gradually increasing the surface temperature of Mars.

By 2080, the average temperature of Mars will reach-15℃, and clouds will appear in the sky. Tundra plants near the equator also began to release oxygen; The polar ice and dry ice began to melt. Gradually, the atmosphere becomes thicker, rivers and lakes are slowly formed, plants grow more vigorously and oxygen is more abundant. This process continues to develop in a benign direction: there are more and more lower animals and plants, more and more oxygen, higher and higher temperatures, and a trickle flows into the sea. By 2 130 years, the temperature of Mars will rise above 10℃; By about 2 170 years, a huge plant system will be enough to enrich the atmosphere with oxygen. At this time, what you see on Mars is: blue sky, green fields, clear rivers, dense forests, everything is so vibrant. At that time, humans finally transformed Mars, which was 100 times worse than Pisa Hara Desert, into the second earth.

In order to solve the energy problem, scientists put forward the idea of satellite solar power station. In the 1970s, many American companies conducted in-depth research on satellite power stations. Boeing has done the most and meticulous work in solar satellite power station. The power station envisaged by the company has two forms: one is photoelectric conversion scheme and the other is Brighton thermal cycle scheme. Each scheme aims to generate 10GW of electricity. The first scheme includes the use of silicon photovoltaic cells and gallium arsenide photovoltaic cells. The second scheme is very similar to the turbine generator on the ground. It relies on a huge cavity heat absorber to absorb solar radiation, and the absorbed heat turns the liquid helium in the circulator into helium, reaching a high temperature of thousands of degrees. When helium expands, it drives the turbine to rotate at high speed through the turbine above. The reflux enters the compressor through the cooler. Turbine-driven compressors and generators can generate AC output of 10000 volts, which is boosted to 330000 volts through transformers and then sent back to the ground in the form of microwaves.

In the United States, scientists and relevant departments are also studying the problem of building solar power stations on the surface of the moon. Research shows that 20,000 solar power stations can be built on the surface of the moon, generating more than 20,000 GW, with an annual income of10.5 trillion US dollars. This figure is equivalent to 60% of the world output value. Although the initial investment is large, the operation and maintenance costs are very low in the future, so it has a very broad development prospect.

Space industrialization is another theme of future space development. The meaning of space industrialization is very broad, which can extend from space processing, production, pharmacy and smelting to space information industry, space tourism and space energy. Longer-term space industrialization also includes the development of moon and planetary resources. Many experts pointed out that the initial stage of space industrialization may trigger a new industrial revolution in medicine, optical glass, electronic devices, magnetic materials, industrial tools, new materials and processing technology.

In the space environment, microgravity and ultra-vacuum make it possible to manufacture bulk semiconductor crystals with high purity and excellent uniformity. Can mass-produce optical fiber and glass materials with uniform stress, high purity and excellent performance; It can produce high-performance alloys, magnetic materials, metal foams and other new materials. Many scientists are very optimistic about producing biological products and special drugs in space. The three major application fields of commercialization of biological products are: biomolecular crystallization, biological separation and living cell culture. The production prospect of special drugs is also very broad. At present, many expensive specific drugs that cannot be mass-produced are expected to be mass-produced in space, and the economic and social benefits are very obvious. The income of materials, processing and biomedical products is conservatively estimated to reach hundreds of billions of dollars. If space information service, space tourism and space energy are included, the total income of space industrialization in the next 15 years will exceed10 billion US dollars.

As can be seen from the above description, the future development prospect of space technology is very broad, and its impact on human society will be far-reaching, but the challenges it faces will also be enormous. Technically, it is necessary to solve the problems of low-cost launch of a large number of loads, assembly of large space structures, industrial production of materials, drugs and other products. Judging from the current situation, the basic technology needed for space city, space immigrants, lunar base and the transformation of Mars has been possessed by human beings, and the feasibility of space production and processing has been verified by experiments. At present, the potential launch capacity of the World Aerospace Year can reach tens of thousands of tons, so it is not too difficult to assemble large space components. So technically, the goal of aerospace industrialization is not far away. Obviously, the huge capital demand will restrict the development of space technology in the future, but the biggest challenge to realize the goal of space industrialization may come from human values and cooperative spirit.