Researchers at the California Institute of Technology (Caltech) have achieved a significant milestone in space technology by successfully demonstrating wireless power transmission in space and beaming detectable energy back to Earth. This pioneering achievement was made possible through an innovative method known as Microwave Array for Power-transfer Low-orbit Experiment (MAPLE).
Advancing Space-Based Solar Power
The successful wireless transmission of energy in space represents a crucial step toward harnessing space-based solar power, offering promising prospects for sustainable energy sources.
How MAPLE Works
MAPLE, developed by Caltech as part of its Space Solar Power Project (SSPP), operates through a network of flexible and lightweight microwave power transmitters. This method utilizes constructive and destructive interference between individual transmitters to precisely direct the energy it beams, all without relying on any moving parts. The technology incorporates precise timing control elements to ensure that the majority of the energy reaches its intended destination.
According to Ali Hajimiri, Bren Professor of Electrical Engineering and co-director of SSPP, “Through the experiments we have run so far, we received confirmation that MAPLE can transmit power successfully to receivers in space. We have also been able to program the array to direct its energy toward Earth, which we detected here at Caltech.”
A Remarkable Achievement
The experiment involved two separate receiver arrays located 30 centimeters away from the transmitter. These receivers converted the received energy into DC electricity, which was then used to illuminate a pair of LEDs, effectively demonstrating the full sequence of wireless energy transmission in space. Researchers conducted these tests in space, individually lighting up each LED and shifting between them to verify the technology’s effectiveness. The transmitted energy from MAPLE was detected by a receiver situated on the roof of the Gordon and Betty Moore Laboratory of Engineering on Caltech’s campus in Pasadena, confirming the expected time, frequency, and frequency shift based on its journey from orbit.
Hajimiri emphasized the significance of this achievement, stating, “To the best of our knowledge, no one has ever demonstrated wireless energy transfer in space even with expensive rigid structures. We are doing it with flexible lightweight structures and with our own integrated circuits. This is a first.”
Space-Based Solar Power’s Potential
The Space Solar Power Project (SSPP) is a research initiative focused on the development and exploration of space-based solar power as a potential solution to address the growing global energy demand. Current solar panels on satellites in geosynchronous orbit receive sunlight for over 99% of the time, yet this energy is primarily used to power the satellite itself. Transmitting this energy via microwaves from space could prove far more efficient than terrestrial solar panels, potentially revolutionizing sustainable energy through an almost limitless source. Moreover, it could provide energy to regions lacking reliable power infrastructure without the need for ground-based energy transmission infrastructure.
“In the same way that the Internet democratised access to information, we hope that wireless energy transfer democratises access to energy,” added Hajimiri.
The SSPP began in 2011 and, with philanthropic support, led to the establishment of a space-based solar power research project. The Space Solar Power Demonstrator (SSPD) prototype was launched into orbit in January of this year as part of the Transporter-6 mission. Alongside MAPLE, SSPD includes two other experiments: Deployable on-Orbit ultraLight Composite Experiment (DOLCE), showcasing space solar panel architecture and deployment mechanisms, and ALBA, testing various photovoltaic cells in the challenging space environment.
Furthermore, China is set to launch a trial satellite in 2028 to test the technology for transmitting energy from a space-based power plant to Earth, highlighting the global interest and potential of space-based solar power.
By Impact Lab