$100M donation powers decade-long moonshot to create photo voltaic satellites that beam energy to Earth – .

It sounds like a villain’s plan if that villain’s insidious end was to supply the whole world with cheap, clean electricity: launch a series of three-mile-wide solar panels that radiate solar energy to the surface. Even the price seems to come from pop fiction: $ 100 million. But this is a real project at Caltech, largely funded by a single donor for nearly a decade.

The space-based solar power project has been running since at least 2013, when Donald and Brigitte Bren’s first donation was received. Donald Bren is Chairman of the Irvine Company and on the Board of Trustees of Caltech. After hearing about the idea of ​​space-based solar energy in Popular Science, he suggested funding a research project at the university – and has since raised over $ 100 million. The source of the funds was kept anonymous until this week when Caltech made it public.

The idea arises, of course, from the current restrictions on renewable energies. Solar energy is ubiquitous on the surface, but of course strongly dependent on the weather, season and time of day. Even under ideal circumstances, no solar panel can operate at full power all the time, and so the problem becomes a problem of energy transmission and storage in a smart grid. That means no solar panel on earth.

However, a solar panel in orbit can be exposed to the full light of the sun almost all of the time, without the degradation of its output caused by that light passing through the protective atmosphere and magnetosphere of the planet.

The latest prototype of the SSPP that collects sunlight and transmits it using microwave frequency.

“This ambitious project is a transformative approach to large-scale solar energy for the earth that overcomes this disruption and the need for energy storage,” said SSPP researcher Harry Atwater in the Caltech press release.

Of course, you’d have to collect enough energy to do it at all, and you need a way to radiate that energy to the surface in such a way that most of it isn’t lost to the protective layers mentioned above, but also doesn’t fry anything that crosses its path .

These fundamental questions have been systematically explored over the past decade and the team is confident that this project would not have been possible without Bren’s support. Trying to get the job done while seeking grants and moving through graduates might have prevented this at all, but the steady funding meant they could hire long-term researchers and overcome early barriers that might otherwise have handicapped them.

The group has created dozens of published studies and prototypes (which you can read here), including the lightest solar panel transmitter by an order of magnitude, and is now close to launching its first space-based test satellite.

“[Launch] is currently expected in the first quarter of 2023, ”Ali Hajimiri, co-director of the project, told .. “These are several demonstrators for space verification of key technologies that are involved in the effort, namely wireless energy transmission over distance, lightweight flexible photovoltaics and flexible space structures.”

Diagram showing how tiles like the one above can be connected into strips, then spacecraft, and then arrays of spacecraft.

These will be small tests (about 6 feet wide) but the vision is for something bigger. In fact, larger than anything currently in space.

“The final system should consist of several deployable modules in close formation flight and operate synchronously with each other,” said Hajimiri. “Each module is several dozen meters to the side and the system can be built up over time by adding more modules.”

Image of what the final space solar installation might look like, a kilometer-wide set of cells in orbit.

Photo credits: Caltech

After all, the concept requires a structure perhaps 5-6 kilometers in diameter. Don’t worry – it would be far enough from Earth that you wouldn’t see a giant hexagon obscuring the stars. The energy would be sent to receivers on the surface using directional, controllable microwave transmission. Some of them in orbit could send full-time electricity to anywhere on the planet.

That, of course, is the vision that is many, many years away, if it is to take place at all. But don’t make the mistake of envisioning this single ambitious, you might say grandiose, goal. The pursuit of this idea has led to advances in solar cells, flexible space-based structures and wireless power transmission, each of which can be applied in different areas. The vision may be the stuff of science fiction, but science advances in a very profound way.

For his part, Bren seems happy just to push the ball forward on what he believes is an important task that otherwise might not have been attempted at all.

“I’ve been a student researching the potential applications of space-based solar energy for many years,” he told Caltech. “My interest in supporting Caltech’s world-class scientists is driven by my belief in harnessing the natural power of the sun for the benefit of all.”

We will check with the SSPP before we start.

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