Revolutionizing Renewable Energy with Space-Based Solar Power: California Institute of Technology Researchers Successfully Transmit Power Wirelessly in Space

Solar Power From Space? California Scientists Make Leap Forward In Wireless Power Transmission

The Need for Space-Based Solar Power (SBSP)

Solar energy is the fastest growing form of renewable energy and currently accounts for 3.6% of global electricity generation, making it the third largest source of renewable energy on the market, followed by hydropower and wind power.

These three modalities are expected to grow exponentially in the coming decades, reaching 40% by 2035 and 45% by 2050. By the middle of the century, renewables are expected to account for 90% of the energy market, and solar power for about half. However, in order for this transition to take place, many technical problems must be solved.

The main limiting factor for solar power is intermittency, which means it can only harvest power when enough sunlight is available. To solve this problem, scientists have spent decades researching space-based solar power (SBSP), in which satellites in orbit will collect energy 24 hours a day, 365 days a year, without interruption.

The California Project

To advance the technology, researchers from the Space Solar Power Project (SSPP) at the California Institute of Technology recently completed the first successful wireless power transfer using the Microwave Array Low Orbit Power Transfer Experiment (MAPLE). MAPLE was developed by a Caltech team led by Ali Hadjimiri, Bren Professor of Electrical and Biomedical Engineering and Co-Director of SSPP.

This platform consists of a group of flexible and lightweight microwave transmitters that are controlled by a special electronic chip. It was built using low-cost silicon technology to collect solar energy and send it to desired receiving stations around the world.

The SSPD-1 Platform

The SSPP program began in 2011 when Donald Brin, a lifetime member of the Caltech Board of Trustees, contacted then-Caltech President Jean Le Chameau to discuss establishing an SBSP research project. Brin and his wife (also a Caltech trustee) agreed to donate a total of $100 million to fund the project, with Northrop Grumman providing an additional $12.5 million. SSPD-1 was launched on Jan. 3 to the surface of a SpaceX Falcon 9 as part of the joint flight program and was deployed by the Vigoride spacecraft (courtesy Momentus).

The SSPD-1 platform consists of individual SSPP units that weigh about 50 kg (110 lb) compared to microsatellites which typically weigh 10 to 100 kg (22 to 220 lb). Each module folds into packages of about 1 cubic meter and then unfolds into a flat square about 50 meters (164 feet) in diameter, with solar panels on one side and wireless power transmitters on the other.

The Next Generation of Solar Satellites

SPT-1 components are not sealed, which means they are subject to sudden temperature changes in space. In addition to proving that power transmitters can survive a launch into space, the experiment provided SSPP engineers with useful information.

“From the experiments we have done so far, we have received confirmation that MAPLE can successfully transmit power to receivers in space,” said Hajimere. “And, of course, we tested it on Earth. But now we know that they can survive the journey into space and work there.”

The team is currently evaluating the performance of individual system components by testing interference patterns from small groups and measuring the difference between combinations. This process can take up to six months, giving the team plenty of time to identify violations and develop solutions to inform the next generation of solar satellites.


With the successful test of MAPLE, the team at California Institute of Technology has taken a major step forward in the development of space-based solar power. SBSP will be an important part of the worldwide transition to renewable energy, and the wireless power transmission technology developed by the SSPP team will contribute to the practicality of SBSP as a reliable source of energy. In the coming years, we can expect more research and development in SBSP, as scientists and engineers work to address the technical issues and challenges that currently stand in the way of space-based solar power.

Source: Science Alert

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