Researchers from the startup Overview Energy have successfully demonstrated beaming power from a moving airplane to the ground using near-infrared light. It marks the first step toward space-based solar power satellites that could someday transmit energy from orbit to existing solar farms on Earth. IEEE Spectrum reports: Overview's test transferred only a sprinkling of power, but it did it with the same components and techniques that the company plans to send to space. "Not only is it the first optical power beaming from a moving platform at any substantial range or power," says Overview CEO Marc Berte, "but also it's the first time anyone's really done a power beaming thing where it's all of the functional pieces all working together," he says. "It's the same methodology and function that we will take to space and scale up in the long term." [...] Many researchers have settled on microwaves as their beam of choice for wireless power. But, in addition to the safety concerns about shooting such intense waves at the Earth, [Paul Jaffe, head of systems engineering] says there's another problem: microwaves are part of what he calls the "beachfront property" of the electromagnetic spectrum -- a range from 2 to 20 gigahertz that is set aside for many other applications, such as 5G cellular networks. "The fact is," Jaffe says, "if you somehow magically had a fully operational solar power satellite that used microwave power transmission in orbit today -- and a multi-kilometer-scale microwave power satellite receiver on the ground magically in place today -- you could not turn it on because the spectrum is not allocated to do this kind of transmission." Instead, Overview plans to use less-dense, wide-field infrared waves. Existing utility-scale solar farms would be able to receive the beamed energy just like they receive the sun's energy during daylight hours. So "your receivers are already built," Berte says. The next major step is a prototype demonstrator for low Earth orbit, after which he hopes to have GEO satellites beaming megawatts of power by 2030 and gigawatts by later that decade. Plenty of doubts about the feasibility of space-based power abound. It is an exotic technology with much left to prove, including the ability to survive orbital debris and the exorbitant cost of launching the power stations. (Overview's satellite will be built on earth in a folded configuration and it will unfold after it's brought to orbit, according to the company). "Getting down the cost per unit mass for launch is a big deal," Jaffe says. "Then, it just becomes a question of increasing the specific power. A lot of the technologies we're working on at Overview are squarely focused on that."
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