Solar Power Satellites: $100M Donation Fuels Space-Based Solar Energy

A Bold Initiative: Space-Based Solar Power

The concept appears almost villainous – a scheme to deploy massive, three-kilometer-wide solar arrays in orbit, beaming clean energy to Earth. Remarkably, the estimated cost of one hundred million dollars echoes the budgets of fictional plots. However, this is a genuine, ongoing project at Caltech, sustained for nearly a decade through substantial funding from a single benefactor.

Funding and Origins

The Space-based Solar Power Project (SSPP) has been in development since at least 2013, initiated by a donation from Donald and Brigitte Bren. Mr. Bren, chairman of Irvine Company and a Caltech trustee, was inspired by an article in Popular Science and subsequently pledged over $100 million to fund research at the university. The source of this funding remained confidential until recently, when Caltech publicly acknowledged it.

Addressing Renewable Energy Limitations

The project stems from the inherent challenges of terrestrial renewable energy sources. While solar power is widely available, its output is significantly affected by weather conditions, seasonal changes, and time of day. Effective energy transfer and storage within a smart grid are crucial, but these limitations do not apply to solar panels positioned in space.

A solar panel in orbit has the potential for near-constant exposure to sunlight, unaffected by atmospheric interference or the Earth’s magnetosphere.

The latest prototype developed by the SSPP, designed to collect sunlight and transmit it via microwave frequency. Image Credits: Caltech

Project Goals and Progress

“This project represents a groundbreaking approach to large-scale solar energy harvesting, overcoming the issues of intermittency and the need for energy storage,” stated SSPP researcher Harry Atwater.

A key challenge lies in efficiently collecting and transmitting sufficient energy without significant loss or causing harm. The team has systematically addressed these fundamental questions over the past decade.

The project’s success is directly attributable to Mr. Bren’s consistent support. Without it, the research might have been hampered by funding constraints and the turnover of graduate students. The sustained funding allowed for the recruitment of long-term researchers and the resolution of initial obstacles.

Prototypes and Upcoming Launch

The group has published numerous studies and developed prototypes, including the lightest solar collector-transmitter to date. They are now preparing to launch their first space-based test satellite.

“[Launch] is currently scheduled for Q1 2023,” explained Ali Hajimiri, co-director of the project, to TechCrunch. “The mission will demonstrate key technologies, including wireless power transfer over distance, lightweight flexible photovoltaics, and deployable space structures.”

Diagram illustrating how tiles can be assembled into strips, spacecraft, and ultimately, arrays of spacecraft. Image Credits: Caltech

These initial tests will involve small-scale deployments, approximately six feet in diameter, but the ultimate vision is far more ambitious.

Future Vision and Scalability

“The envisioned final system will comprise multiple deployable modules operating in synchronized formation,” Hajimiri added. “Each module will be several tens of meters across, and the system can be expanded by adding more modules over time.”

Image Credits: Caltech

The long-term concept involves a structure potentially spanning 5-6 kilometers. However, it would be positioned at a sufficient distance from Earth to avoid obstructing the view of the stars. Power would be transmitted to ground-based receivers using directed, steerable microwave beams, enabling continuous power delivery to any location on the planet.

Beyond the Vision: Tangible Advancements

While this remains a long-term goal, the pursuit of space-based solar power has already yielded significant advancements in solar cell technology, flexible space structures, and wireless power transfer – all with applications beyond this specific project. The core science is progressing in a practical and methodical manner, even if the overall vision resembles science fiction.

Mr. Bren expressed his satisfaction with the project’s progress, emphasizing his belief in harnessing solar energy for global benefit.

“I have been researching the potential of space-based solar energy for years,” he stated to Caltech. “My support for Caltech’s scientists is driven by my conviction in utilizing the sun’s power for the betterment of all.”

We will continue to follow the SSPP’s progress as they approach launch.