Caltech’s Space Solar Power Mission Ends With Key Insights

A Year After Launch, Space Solar Power Mission ends, Draws Crucial Lessons. Photo: Pexels

Caltech’s Space Solar Power Demonstrator (SSPD-1), launched into space a year ago to demonstrate and test three technological innovations necessary to make space solar power a reality. The spaceborne testbed demonstrated the ability to beam power wirelessly in space. It measured the efficiency, durability, and function of a variety of different types of solar cells in space. It also gave a real-world trial of the design of a lightweight deployable structure to deliver and hold the aforementioned solar cells and power transmitters.

SSPD-1 is a milestone in a project that has been underway for more than a decade, having drawn international attention as a high-profile step forward for a technology being pursued by multiple nations. It was launched on January 3, 2023, aboard a Momentus Vigoride spacecraft as part of the Caltech Space Solar Power Project.

With the culmination of SSPD-1’s mission in space, there have been important lessons that will help chart the future of space solar power.

“Solar power beamed from space at commercial rates, lighting the globe, is still a future prospect. But this critical mission demonstrated that it should be an achievable future,” says Caltech President Thomas F. Rosenbaum, the Sonja and William Davidow Presidential Chair and professor of physics.

The project began after philanthropist Donald Bren, chairman of Irvine Company and a life member of the Caltech community, first learned about the potential for space-based solar energy manufacturing. “The hard work and dedication of the brilliant scien­tists at Caltech have advanced our dream of providing the world with abundant, reliable, and affordable power for the benefit of all humankind,” said Donald Bren.

With SSPD-1 winding down its mission, the testbed stopped communications with Earth on November 11. The Vigoride-5 vehicle that hosted SSPD-1 will remain in orbit to support continued testing and demonstration of the vehicle’s Microwave Electrothermal Thruster engines that use distilled water as a propellant. It will ultimately deorbit and disintegrate in Earth’s atmosphere. Meanwhile, the SSPP team continues work in the lab, studying the feedback from SSPD-1 to identify the next set of fundamental research challenges for the project to tackle.