Emerging Space-Based Solar Technologies Promise New Frontiers in Renewable Energy
The concept of harnessing solar power from space and transmitting it to Earth is transitioning from science fiction to a tangible possibility. As the global shift towards renewable energy accelerates, the idea of using space-based solar systems to complement terrestrial solar power is gaining significant traction.
Traditionally, solar photovoltaic (PV) systems have been employed to power satellites in orbit. However, the focus is now shifting towards the feasibility of using these satellites to redirect solar energy back to Earth. This approach could address energy demands, particularly during periods when terrestrial solar power generation is limited, such as dawn, dusk, and nighttime.
Recent advancements in space-based solar technology include innovative concepts like the ‘Solspace’ project at the University of Glasgow. Funded by a five-year European Research Council grant since 2020, this initiative explores satellite orbital dynamics, solar reflector design, and economic viability. According to a study published in April 2024 in Acta Astronautica, the project proposes deploying a constellation of satellites equipped with 1-kilometer diameter reflectors in low Earth orbit. Initial findings suggest that a network of five reflectors could extend the operational hours of a solar power farm by approximately 35 minutes, while 20 reflectors could extend this period by over 1.5 hours.
The European Space Agency (ESA) is also examining similar concepts through its Solaris space-based solar program. This initiative aims to serve as a precursor to more complex radio frequency solar power satellites. Given its simpler technical requirements, the Solaris program could provide valuable insights and test technologies for future, more advanced systems.
A feasibility study conducted by consultancy Arthur D. Little, in collaboration with energy supplier Engie and other partners, envisions a constellation of nearly 4,000 mirrors, each 1 kilometer in diameter, in low Earth orbit. This setup could potentially illuminate a solar farm for up to two hours during dawn and dusk, delivering power at 1 kW/m². The study suggests that a scaled-down prototype could be operational by 2030, with full-scale deployment projected for 2043.
Amid these developments, California-based Reflect Orbital has emerged as a key player in the space-based solar market. The company aims to sell both sunlight and energy, with its first delivery expected in the fourth quarter of 2025. Reflect Orbital plans to launch a constellation of 57 small satellites, each equipped with 10×10-meter mylar mirrors. These satellites are designed to provide an additional 30 minutes of sunshine at power plants or create 4-minute duration sunlight beams with a 5-kilometer diameter at selected locations. Reflect Orbital has reportedly tested its mirror technology using a hot air balloon, generating 0.5 kW/m², and has secured funding for its inaugural space mission scheduled for next year.
While Reflect Orbital’s ambitious goals are generating significant media buzz, the company’s focus appears to be on building interest and securing additional funding. The practical implementation of space-based solar technologies, as demonstrated by ongoing projects and studies, will likely require several years of development and testing before becoming a widespread reality.
As these space-based solar initiatives progress, they could revolutionize the way we generate and consume energy, marking a significant leap forward in the quest for sustainable power solutions.
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