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Solar Power From Space Successfully Beamed to Earth

A Caltech team is celebrating the world's first space-based wireless power transmission, and the first time detectable levels of power have been beamed down to Earth. The Space Solar Power Project (SSPP) aims to unlock huge orbital clean energy resources.

Illustration of Caltech's space solar array
Credit: Caltech

Space-based solar could solve a lot of Earth's clean energy problems because an orbital solar setup doesn't get affected by weather conditions and can harvest sunlight 24/7. Furthermore, at least theoretically, the solar potential in space is eight times better per square meter than a solar panel on Earth. So, it's not surprising that the Caltech team isn't the only venture attempting to test out harvesting sunshine in space - 100 miles or so above Earth.

The Caltech project is charging full steam ahead, buoyed by more than US$100 million's worth of donations. And it's now announced the results of its first phase orbital prototype testing.

Firstly, they were able to validate their beam-steering technology in the harsh temperatures and radiation environment of space. Secondly, the team's transmitter array was able to beam energy directly down to Earth, aimed at a receiver unit on the roof of an engineering lab at Caltech Pasadena. The power beam was detected at the ground station, at the expected time and frequency, and with the correct frequency shift predicted based on the distance traveled.

This wasn't a useful amount of power, but it validates the team's ability to precisely target a power beam over great distances, and confirms that the gear involved can survive the trip to orbit.

It's clearly still early days, but harvesting solar power from space just took a major step forward.


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