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The future of air travel may not be gigantic turtle-shaped airships, but Japan hopes to test another idea straight out of science fiction, solar power stations in space, within the next two decades.
Scientific American is running a piece in their June issue which discusses the ambitious, orbital solar energy plans currently being discussed by Japan’s space agency. Without giving it all away, here are the main points:
Laser or Microwave to trasmit energy to Earth
The plan would consist of a solar-power generator in geostationary orbit which would collect the solar energy and transmit it in either microwave or laser form to a receiving station on the planet surface.
The form this research is currently taking is a bit more grounded: An 800 watt optical-fiber laser is fired at a receiving station 500 meters away. This beam is bounced off a mirror that reflects only 1,064-nanometer wavelength light—the frequency found to most easily pass through the Earth’s atmosphere. This beam would carry the solar energy to a receiving station back on Earth. The key task at the moment is finding a material that efficiently can convert sunlight into a laser beam.
Project would be massive, physically and financially
If and when this project is completed, it is envisioned that it will have to be physically massive, let alone costly: the orbiting solar portion could stretch for kilometers and weight 10,000 tonnes; the laser portion could be as long as 10 kilometers; the ground-based receiving unit could be up to two kilometers long. The whole project could cost tens of billions of dollars, according to Hiroaki Suzuki, one of the 180 scientists working on the scheme.
Japan is not the first nation to explore the possibilities of harnessing solar energy from space: India and Palauhave also vetted the idea. As you might expect, the Pentagon also thinks orbiting solar panels are worth investigating