$100M donation powers decade-long moonshot to create solar satellites that beam power to Earth – TechCrunch

by Joseph K. Clark

It sounds like a plan concocted by a supervillain if that villain’s dastardly end was to provide cheap, clean power worldwide: launch a set of three-kilometer-wide solar arrays that beam the sun’s energy to the surface. Even the price tag seems gleaned from pop fiction: one hundred million dollars. But this project at Caltech has been funded for nearly a decade, mainly by a single donor.

The Space-based Solar Power Project has been underway since at least 2013, when the first donation from Donald and Brigitte Bren came through. Donald Bren is the chairman of Irvine Company. On the Caltech board of trustees, and after hearing about the idea of space-based solar in Popular Science, he proposed to fund a research project at the university — and since then has given over $100M for the purpose. The funds’ source was kept anonymous until this week when Caltech made it public.

The idea emerges naturally from the current limitations of renewable energy. Solar power is ubiquitous on the surface but highly dependent on the weather, season, and time of day. Even in ideal circumstances, no solar panel can always work at total capacity, so the problem becomes one of transferring and storing energy in an intelligent grid. No solar panel on Earth, that is.

solar satellites

However, a solar panel in orbit may be exposed to the whole light of the sun nearly all the time, and with none of the reduction in its power that comes from that light passing through the planet’s protective atmosphere and magnetosphere. The latest prototype was the SSPP, which collects and transmits sunlight over microwave frequency.

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

Of course, you would need to collect enough energy that it’s worth doing in the first place, and you need a way to beam that energy down to the surface in a way that doesn’t lose most of it to the aforementioned protective layers but also doesn’t fry anything passing through its path.

These fundamental questions have been looked at systematically for the last decade, and the team is clear that this project wouldn’t have been possible without Bren’s support. Attempting to do the work while scrounging for grants and rotating through grad students might have prevented it from being done. Still, the steady funding meant they could hire long-term researchers and overcome early obstacles that might have hindered them otherwise.

The group has produced dozens of published studies and prototypes (which you can peruse here), including the lightest solar collector transmitter made by order of magnitude. It is now on the verge of launching its first space-based test satellite.

“[Launch] is currently expected to be Q1 2023,” co-director of the project Ali Hajimiri told TechCrunch. “It involves several demonstrators for space verification of key technologies involved in the effort, namely, wireless power transfer at a distance, lightweight, flexible photovoltaics, and flexible, deployable space structures.”

These will be small-scale tests (about 6 feet across), but the vision is for something somewhat more significant. More extensive than anything currently in space. “The final system is envisioned to consist of multiple deployable modules in close formation flight and operating in synchronization,” Hajimiri said. “Each module is several tens of meters on the side, and the system can be built up by adding more modules over time.”

Eventually, the concept calls for a structure as large as 5-6 kilometers across. Don’t worry — it would be far enough from Earth that you wouldn’t see a giant hexagon blocking the stars. Power would be sent to receivers on the surface using directed, steerable microwave transmission. A few of these in orbit could beam energy to any location on the planet full-time.

Of course, that is the vision, which is many years out if it is to take place at all. But don’t mistake thinking of this as having that single ambition; one might even say grandiose goal. PThe vision may be the stuff of science fiction, but science progresses in a very grounded way. Pursuing this idea has produced advances in solar cells, flexible space-based structures, and wireless power transfer, which can be applied in other areas. For his part, Bren seems to be happy to advance the ball on what he considers an important task that might not otherwise have been attempted.

“I have been a student researching the possible applications of space-based solar energy for many years,” he told Caltech. “My interest in supporting the world-class scientists at Caltech is driven by my belief in harnessing the sun’s natural power for the benefit of everyone.” We’ll check back with the SSPP ahead of the launch.

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