Is It Possible to Beam Solar Power From Outer Space?

"[F]or years it was written off," writes CNN. " 'The economics were just way out,' said Martin Soltau, CEO of the UK-based company Space Solar. "That may now be changing as the cost of launching satellites falls sharply, solar and robotics technology advances swiftly, and the need for abundant clean energy to replace planet-heating fossil fuels becomes more urgent." There's a "nexus of different technologies coming together right now just when we need it," said Craig Underwood, emeritus professor of spacecraft engineering at the University of Surrey in the U.K. The problem is, these technologies would need to be deployed at a scale unlike anything ever done before... "The big stumbling block has been simply the sheer cost of putting a power station into orbit." Over the last decade, that has begun to change as companies such as SpaceX and Blue Origin started developing reusable rockets. Today's launch costs at around $1,500 per kilogram are about 30 times less than in the Space Shuttle era of the early 1980s. And while launching thousands of tons of material into space sounds like it would have a huge carbon footprint, space solar would likely have a footprint at least comparable to terrestrial solar per unit of energy, if not a smaller, because of its increased efficiency as sunlight is available nearly constantly, said Mamatha Maheshwarappa, payload systems lead at UK Space Agency. Some experts go further. Underwood said the carbon footprint of space-based solar would be around half that of a terrestrial solar farm producing the same power, even with the rocket launch... There is still a huge gulf between concept and commercialization. We know how to build a satellite, and we know how to build a solar array, Maheshwarappa said. "What we don't know is how to build something this big in space..." Scientists also need to figure out how to use AI and robotics to construct and maintain these structures in space. "The enabling technologies are still in a very low technology readiness," Maheshwarappa said. Then there's regulating this new energy system, to ensure the satellites are built sustainably, there's no debris risk, and they have an end-of-life plan, as well as to determine where rectenna sites should be located. Public buy-in could be another huge obstacle, Maheshwarappa said. There can be an instinctive fear when it comes to beaming power from space. But such fears are unfounded, according to some experts. The energy density at the center of the rectenna would be about a quarter of the midday sun. "It is no different than standing in front of a heat lamp," Hajimiri said. The article argues that governments and companies around the world "believe there is huge promise in space-based solar to help meet burgeoning demand for abundant, clean energy and tackle the climate crisis." And they cite several specific examples:In 2020 the U.S. Naval Research Lab launched a module on an orbital test vehicle, to test solar hardware in space conditions. This year Caltech electrical engineering professor led a team that successfully launched a 30-centimeter prototype equipped with transmitters - and successfully beamed detectable energy down to earth.In June the U.K. government announced over $5 million in funding to universities and tech companies "to drive forward innovation" in the space-based solar sector. The U.S. Air Force Research Lab plans to launch a small demonstrator in 2025.Europe's its Solaris program aims to prove "the technical and political viability of space-based solar, in preparation for a possible decision in 2025 to launch a full development program."One Chinese spacecraft designer and manufacturer hopes to send a solar satellite into low orbit in 2028 and high orbit by 2030, according to a 2022 South China Morning News report.

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