The greatest challenge for China to develop space

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The impact of space solar energy on small loads and the huge challenges faced by large power stations in China

the enormous solar photovoltaic cell array is placed in the earth orbit to form a solar power station, and the solar photovoltaic power generation device converts solar energy into electric energy. In 1968, peterglasser, an American scientist, first put forward the idea of building a space solar photovoltaic power station. The basic idea is to place an incomparably large array of solar photovoltaic cells in earth orbit to form a solar photovoltaic power station, convert the inexhaustible and inexhaustible solar energy into thousands of megawatts of electric energy, and then convert the electric energy into microwave energy, which is transmitted to the earth by microwave or wireless technology

the energy conversion device converts the electric energy into microwave or laser (the laser can also be directly converted through solar energy), and sends the energy beam to the ground using the antenna. According to some data, theoretically speaking, on the sunny geostationary orbit, the solar energy can generate 1336 watts of heat per square meter. If a 1000 meter wide solar photovoltaic array ring is deployed on the upper part of the geostationary orbit, assuming that its conversion efficiency is 100%, then the solar radiation flux it receives in a year is almost equal to the total energy contained in the known exploitable oil reserves on the earth

the ground receiving system receives the energy beam from the space solar power station, and then repairs the spine through the conversion device to reduce complications: in recent years, it has been converted into cobalt material environmental risk electric energy. The whole process experienced the energy transformation process of solar energy - electric energy - microwave (laser) - electric energy. The construction and operation of space solar photovoltaic power plants also need to include large-scale transportation systems, space transportation systems, and complex logistics support systems

at present, the construction of space solar power station is the first technical problem. The space solar power station is a huge project, which poses great challenges to the existing spacecraft technology: it is large in scale, with a mass of more than 10000 tons, four orders of magnitude higher than the current satellites, and requires the use of new materials and new delivery technologies; With an area of more than several square kilometers, which is six orders of magnitude higher than the current satellite, special structure, space assembly and attitude control technology are required; High power, generating power of gigawatts, 6 orders of magnitude higher than the current satellite, requiring special power management and thermal control technology; It has a long service life of at least 30 years, more than twice that of current satellites, and requires new materials and on orbit maintenance technology; High efficiency requires advanced space solar energy conversion technology and microwave conversion and transmission technology

the second is cost. Some experts estimate that it will cost US $300billion to US $100billion to build a space-based solar power station. Therefore, the cost problem may be the main factor restricting the development of space solar power plants. Before new concepts, new technologies and large-scale commercialization, it is difficult for revenue to compensate for the construction and operation costs of the entire system

environmental impact. Although the power of the space solar power station is very large, the energy density of the actual receiving antenna is relatively low due to the long transmission distance of microwave energy (36000 km)

finally, there is a running problem. There are still many problems in the operation of space solar power plants, including the need to take corresponding measures to safely control the beam, the impact on aircraft, the possibility that space debris may cause local damage to space solar power plants, vulnerability, and may become space garbage. In addition, there are orbit and frequency, production capacity, launch capacity and other issues

extraterritorial scheme

American 1979sps benchmark system: This is the first relatively complete system design scheme for space solar power station, which was completed by the United States in 1979 and designed with half of the power generation of the whole United States as the goal. The design scheme is to arrange 60 power generation satellites with a power generation capacity of 5 GW each in the geostationary orbit

integrated symmetrical focusing system: a scheme proposed by NASA in the SERT research program in the late 1990s. Large clamshell shaped concentrators located on both sides of the mast are used to reflect the solar energy to two photovoltaic arrays located in the center. The concentrator faces the sun, and the mast, battery array and emission array are integrated, rotating to the ground. The concentrator and mast rotate with each other to cope with daily track changes and seasonal changes

Japanese distributed tethered satellite system: in order to reduce the complexity and weight of a single module, Japanese scientists put forward the concept of distributed tethered satellite. Its basic unit consists of 100 meters × The 95m unit plate is composed of a satellite platform, which is suspended together by four 2-10 km ropes. The unit board is a sandwich structure board composed of solar cells, microwave conversion devices and transmitting antennas, which contains 3800 components in total. The total weight of each unit board is about 42.5 tons, and the microwave energy transmission power is 2.1 MW. It consists of 25 unit boards to form a daughter board, and 25 daughter boards to form the whole system. The modular design idea of the design scheme is very clear, which is conducive to the assembly and maintenance of the system. However, the quality of the system is still huge, especially the utilization efficiency is low

European solar sail Tower: in 1998, Europe put forward the concept of European solar sail tower in the "Research on system concept, structure and technology of space and exploration and utilization". The scheme is based on the solar tower concept proposed by the United States and adopts many new technologies. The most important one is the deployable light structure - solar sail. It can greatly reduce the total weight of the system and reduce the assembly difficulty of the system. Each solar sail array is a module with a size of 150m × 150m, automatically deployed after launching into orbit, assembled in low earth orbit, and then transferred to geosynchronous orbit through electric thruster. Because the scheme adopts gradient stability to realize the Earth Orientation of the transmitting antenna, the solar array can not realize the continuous sun orientation

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