The Race to Harness Unlimited Solar Power from Space
Global initiatives are reviving space-based solar power to provide constant, clean energy for Earth.
1The Orbital Energy Vision
Space-based solar power involves satellite clusters harvesting sunlight in orbit and beaming it to Earth. While once dismissed as science fiction, major projects like China's ZhuRi and Japan's OHISAMA are now reassessing feasibility. These initiatives aim to provide constant, clean energy by bypassing the atmospheric limitations that hinder terrestrial solar panels.
2Historical Conceptual Roots
The concept dates back to 1923 with Konstantin Tsiolkovsky’s proposal for space-based mirrors. Later, Isaac Asimov popularized the idea in fiction, while aerospace engineer Peter Glaser formalized the first engineering design in 1968. Glaser’s model focused on photovoltaic disks in geostationary orbit, converting harvested solar energy into microwaves for transmission to ground-based antennae.
3Early Economic Roadblocks
In 1981, a U.S. Department of Energy study deemed space-based solar power unaffordable due to massive scale requirements. It estimated that 300 gigawatts of power would necessitate 60 satellites, each weighing 45,000 metric tons. Subsequent reports, including a 2015 U.S. Army War College assessment, maintained that the technology lacked economic competitiveness against terrestrial systems.
4The Impact of Reusable Rockets
Launch costs have plummeted significantly since the introduction of SpaceX’s reusable Falcon 9 rocket, which is roughly 30 times cheaper than the Space Shuttle. This shift, combined with mass-produced satellite components, has fundamentally changed the economic calculus. Future capacity from the Starship rocket promises to lower payload costs even further for orbital deployment.
5U.K. Government Investment
A 2021 U.K. government assessment estimated that a 2-gigawatt solar array could generate electricity at 50 British pounds per megawatt hour. This cost is competitive with biomass and nuclear energy. Consequently, the U.K. awarded 4.3 million British pounds in 2023 to support companies and universities in developing advanced space-based solar power architectures.
6The CASSIOPeiA Design Innovation
Space Solar’s CASSIOPeiA satellite features a unique DNA-strand shape designed to maximize solar collection without failure-prone moving parts. By utilizing a slow spin and sun-synchronous orbit, a single 1.6-kilometer-wide satellite could beam 2 gigawatts of constant power. This design aims to solve the alignment challenges that plagued earlier, more complex satellite blueprints.
7Efficiency Gains in Orbit
Space-based solar is significantly more efficient than ground-based alternatives because sunlight is not attenuated by the atmosphere. Sam Adlen of Space Solar notes that materials are 100% utilized in space, compared to only 10% on the ground. This allows for 13 times more instant energy generation from the same amount of solar panel material.
8Microwaves Versus Laser Beaming
Power transmission methods are currently split between lasers and microwaves. While infrared lasers are efficient, they scatter in cloudy weather. Conversely, microwaves suffer less atmospheric attenuation, making them the preferred choice for utility-scale projects like China's ZhuRi. However, microwave beams require massive Earth-based receivers, spanning dozens of square miles to capture the transmitted energy.
9Technical Hurdles in Transmission
Beaming gigawatts of power through the atmosphere remains a major engineering challenge. Startups like Aetherflux are testing infrared laser systems, while Caltech has demonstrated small-scale microwave transmission. Current technology requires significant advancements to scale these experiments to the gigawatt level, as beam diffraction necessitates extremely large ground-based receiving stations for microwave signals.
10Security and Safety Concerns
High-intensity power beams raise potential security questions regarding electronic interference. Experts note that even if lasers cannot destroy hardened targets, they could potentially freeze sensitive electronics. Companies like Aetherflux are developing safety mechanisms, such as automatic shut-off protocols, to ensure beams are deactivated if any object passes between the transmitter and the receiver.
11Simpler Reflective Alternatives
Some researchers are revisiting simpler concepts, such as deploying space-based mirrors to reflect sunlight toward ground-based solar farms after sunset. Onur Celik of the University of Glasgow suggests that multiple reflectors could extend daylight by up to two hours. This approach could potentially power thousands of homes without the complexities of microwave power beaming.
12Future Outlook and Viability
While the U.K. government estimates costs comparable to offshore wind, 2024 NASA projections suggest higher baseline costs. The path to viability depends on overcoming transmission efficiency and launch scale. As the industry moves toward test launches, the debate continues over whether space-based solar can realistically contribute to the urgent global green-energy transition.
Original article: Latest from Live Science — The Race to Harness Unlimited Solar Power from Space