Cal-Tech Scientists Transmit Space-Based Solar Power to Earth For First Time

In an amazing breakthrough for energy development, scientists from the California Institute of Technology have successfully demonstrated that solar energy can be collected in space and beamed down to Earth in a seemingly endless supply.

The institution announced Thursday a power signal transmitted by a small demonstration unit orbiting 550 kilometers above the planet was recently detected by a receiver on the rooftop of a laboratory on Caltech’s Pasadena campus.Ali Hajimiri, Bren professor of electrical engineering and one of two co-directors on the project, confirmed transmission occurred May 22.“It took a few moments for it to sink in, then everybody got really excited,” he said in an interview Thursday. “This technology for wireless energy transfer can have a tremendous impact on lives, both on Earth and in space.”The 50-kilogram Space Solar Power Demonstrator (SSPD-1) is testing three key technologies that would make it possible to convert sunlight into electrical energy and then send it in the form of microwaves to receivers anywhere on the planet.

The wireless power transfer was demonstrated by MAPLE (Microwave Array for Power-transfer Low-orbit Experiment). The array was one of three key technologies that were being tested being tested. The unit consists of an array of flexible, lightweight microwave power transmitters driven by custom electronic chips that were built using low-cost silicon technologies.

It uses the array of transmitters to beam the energy to desired locations. For SSPP to be feasible, energy transmission arrays will need to be lightweight to minimize the amount of fuel needed to send them to space, flexible so they can fold up into a package that can be transported in a rocket, and a low-cost technology overall.MAPLE was developed by a Caltech team led by Ali Hajimiri, Bren Professor of Electrical Engineering and Medical Engineering and co-director of SSPP.“Through the experiments we have run so far, we received confirmation that MAPLE can transmit power successfully to receivers in space,” Hajimiri says. “We have also been able to program the array to direct its energy toward Earth, which we detected here at Caltech. We had, of course, tested it on Earth, but now we know that it can survive the trip to space and operate there.”

Meanwhile, the Japanese are working on similar technology that will attempt to beam solar energy from space in 2025.

Nikkei reports a Japanese public-private partnership will attempt to beam solar energy from space as early as 2025. The project, led by Naoki Shinohara, a Kyoto University professor who has been working on space-based solar energy since 2009, will attempt to deploy a series of small satellites in orbit. Those will then try to beam the solar energy the arrays collect to ground-based receiving stations hundreds of miles away.Using orbital solar panels and microwaves to send energy to Earth was first proposed in 1968. Since then, a few countries, including China and the US, have spent time and money pursuing the idea. The technology is appealing because orbital solar arrays represent a potentially unlimited renewable energy supply. In space, solar panels can collect energy no matter the time of day, and by using microwaves to beam the power they produce, clouds aren’t a concern either.However, even if Japan successfully deploys a set of orbital solar arrays, the tech would still be closer to science fiction than fact. That’s because producing an array that can generate 1 gigawatt of power – or about the output of one nuclear reactor – would cost about $7 billion with currently available technologies.

It costs about $5 billion to build one nuclear power plant. So, a solar array would be marginally more expensive.

I am for developing both technologies, as we will see which one can deliver the energy goods.

Tags: California, College Insurrection, Energy, Space

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