2. Even Edison’s power station, the first commercial electric power station, was only a few hundred horse-power in generating capacity. It is not necessary for the first SPS to be competitive with large power stations in industrialized nations. Considering the high costs of available launch systems, the first SPS should be reasonably small to be accepted by concerned organizations. 3. The cost of existing space technology is too high to be applied in the power industry. The cost of power stations must be low enough to be attractive from the standpoint of financing. 4. The first SPS should be useful not only to demonstrate technical feasibility, but also to prove to be useful to people on the Earth, especially for developing nations where even small amounts of electric power are useful. In planning to build a first power station in space, among the various design drivers of this new system, we have chosen COST as the key driver. It is believed that launch cost is the most difficult target to reach. However, our study indicates that the cost of present space technology is the main hurdle to clear for construction of a space power station. A rough estimation of the cost per kilowatt for construction of a 10 MW solar power satellite by the space industry is one thousand times higher than that for terrestrial power stations. One may note the fact that the payment for a three-minute telephone call via satellite is more than ten times as expensive as one kilowatt-hour of electricity. That represents the cost-ratio between the present space technology and SPS technology. The next phase is to reduce the cost for launching. We are rather optimistic on this matter since its possibility is already under discussion. The configuration of SPS 2000 in the initial phase of conceptual design has changed because of engineering reasons. The geometry of the SPS is a prism-shape, and it has neither active attitude control, nor sun-oriented solar panels, in order to simplify the control system. We found that a solar power station should be as simple as a terrestrial solar power station, considering the maintenance cost. The modified geometry satisfies the requirement of passive attitude stabilization. Now, researchers and engineers are working to design the construction method for the system in orbit, and also to choose inexpensive technology. Antenna design, overall system dynamics and integration for launching are other important subjects. There are many other subjects concerning the satellite needing further study, but another important area of study is power reception and utilization. The SPS 2000 microwave beam will cover an area of approximately 1500 metres in diameter at the Earth’s surface, about the size of an airport. The SPS receiving antenna is known as a rectenna because it rectifies microwaves to DC, and the surface is a lightweight mesh transparent to sunlight, so that the land underneath can be used for other purposes.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==