In an experiment that tested technology that could one day be used to transmit solar energy from satellites to Earth, researchers beamed solar energy from one Hawaiian island to another, across a distance of 92 miles. The $1 million experiment was sponsored by the Discovery Channel, which aired an episode about the technology on its Project Earth show on Friday.
The experiment was intended as a proof of concept for an ambitious proposal that calls for huge arrays of solar panels to orbit the Earth, collecting pristine solar radiation, free from the day/night cycles, weather and atmospheric effects that limit solar radiation down on the ground. The energy collected will be “beamed” down to power stations on the surface, either by microwave (or an alternative system, by laser) — and then distributed as normal power across the grid [Discovery Channel]. Backers of this space-based solar technology say the potential benefits are enormous; the non-profit National Space Society says that the sun puts out billions of times more energy than our planet’s population uses.
This experiment, however, operated on a very small scale. Although the amount of power sent, 20 watts, is barely enough to power a small compact fluorescent light bulb, and most of it was lost in transmission, the system was limited by the budget not the physics [Wired News]. The experiment’s leader, former NASA executive and physicist John Mankins, said that if they had been able to afford more solar panels and better receivers they could have boosted efficiency considerably.
Solar-powered satellites won’t just be appearing on TV; both the U.S. military and the Japanese space agency are working on projects of their own. [T]he Air Force Academy recently announced plans for a small demonstration satellite that would beam down a meager, but still significant, 0.1 watts of solar power. “Our vision is to build the world’s first-ever space-based solar power system to light a single bulb on Earth and in so doing light the path for business to follow,” said Col. Michael “Coyote” Smith of the Air Force. [Meanwhile, Japan's] goal is to launch a geostationary satellite by 2030 that could supply 500,000 homes on Earth with a gigawatt of power [LiveScience].
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