Adapted by:
Matías S. Zavia
WriterAerospace and energy industries journalist at Xataka.
Alba Mora
WriterAn established tech journalist, I entered the world of consumer tech by chance in 2018. In my writing and translating career, I've also covered a diverse range of topics, including entertainment, travel, science, and the economy.
In 1941, science fiction writer Isaac Asimov published a short story titled Reason. In it, he envisioned a satellite that transmits energy from the Sun to Earth and other colonies in the solar system using microwave beams. Today, his idea is closer to becoming a reality.
From Asimov to the Cold War era. The first technical proposal to capture solar energy in space and transmit it to Earth arose in 1968. American engineer Peter Glaser, who was born in Czechoslovakia, patented the concept of a satellite in geostationary orbit for transmitting solar energy via microwaves.
During the 1970s, amid an energy crisis caused by oil shortages, NASA and the Department of Energy began exploring space-based solar power as a potential large-scale renewable energy source.
Alongside Raytheon, a now-defunct Pentagon defense contractor, NASA and the DOE conducted the first wireless power transmission demonstration in 1975. The proof-of-concept test at the agency’s Goldstone facility successfully transmitted 914 watts at 54.18% efficiency, but only over a distance of 5 feet.
Ups and downs. Despite designing large orbital solar stations, NASA concluded that the concept was too expensive for the technology available in the 1970s and ultimately shelved the project.
Interest in space solar power was revived in the late 1990s when the Japan Aerospace Exploration Agency began developing two concepts based on low-Earth and geostationary orbits.
In 2015, Japan wirelessly transmitted 1.8 kilowatts of power with millimeter precision to a receiving antenna located 165 feet away, setting a world record then. The Asian nation is currently advancing its plan to construct a 1-gigawatt solar orbital station by 2030.
Renewed attention. In recent years, Japan has inspired other countries to consider filling Earth’s orbit with solar panels. Photovoltaic technology has advanced significantly. Panels today are smaller, lighter, more flexible, and potentially capable of self-assembly. Notably, SpaceX has been a major factor driving this renewed interest.
SpaceX’s reusable rockets have demonstrated that launch costs can be drastically reduced, eliminating one of the major economic barriers to space-based solar power. Space-based solar power holds a distinct advantage as the world seeks clean energy solutions to meet net emissions targets. Unlike terrestrial energy sources, it can operate continuously as long as panels in orbit face the Sun.
China’s role. China is leading the global investment in space-based solar power. A few years ago, Xidian University in North Central China constructed a nearly 250-foot-high tower to test wireless power transmission from space. Several ground stations are currently under development.
For its part, the China Academy of Space Technology has outlined a four-phase development plan for this initiative. By 2028, it expects to launch a 10 kW station in low-Earth orbit to demonstrate wireless power transmission over a distance of 250 miles.
By 2030, the Chinese academy plans to deploy a megawatt-scale station in geostationary orbit that will transmit power over a distance of 22,400 miles. By 2035, the station’s capacity is expected to increase to 10 MW. Finally, by 2050, the project aims for a completed station with a power output of 2 GW.
American robots. The U.S. is approaching this challenge through a public-private partnership. DARPA is collaborating with Aetherflux, a Californian company that plans to launch a prototype satellite into low Earth orbit next year. This follows a successful demonstration by Caltech University in 2023, which showcased power transmission from space.
Additionally, the U.S. has developed a crucial technology for building solar power stations: the robotic assembly of solar panels. Robotics automation startup Orbital Composites and space technology manufacturer Virtus Solis have designed 5.4-foot panels that robots will assemble in medium Earth orbit. As a result, the possibilities for constructing a solar farm capable of transmitting power continuously have dramatically increased.
Europe’s decision. The European Space Agency has been operating the SOLARIS program since 2022. This program evaluates the feasibility of space solar power. SOLARIS has awarded contracts to companies such as Airbus and Thales Alenia Space to explore the development of commercial-scale space solar stations.
These studies investigate several concepts, including microwave-emitting satellites and alternatives like orbital mirrors. The goal is to provide information that will help inform a decision later this year on whether Europe should pursue a comprehensive space solar power development program.
Image | NASA
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