Space solar panels sound like science fiction, but according to a new study, they could make a big difference pretty soon. According to the study, which focused on Europe, they could reduce the continent’s battery needs by more than 70% by 2050. Especially if you work with something called a heliostat swarm.
In the late 1960s, an engineer named Peter Glaser floated a wild idea: what if we launched giant solar panels into orbit and beamed the power back to Earth? At the time, it sounded like something out of a pulp science magazine, up there with moon colonies and nuclear-powered cars. But then again, so did ground-based solar panels until not that long ago.
Ten years ago, solar panels provided just around 1% of the global electricity. Now, they provide over 7%, and are already the most affordable form of energy in most parts of the world. In fact, globally, solar power has gone from an outlier to the cheapest form of energy in history and shows no signs of slowing down; in fact, it’s accelerating so much that the biggest problem now isn’t energy generation, but storage.
But why would we move them in space?
The appeal is straightforward. Solar panels on Earth depend on weather. They shut down at night, sulk under clouds, and fade during winter. In contrast, a solar array parked 36,000 kilometers above the equator would bask in nearly uninterrupted sunlight.
“In space, you potentially have the ability to position solar panels to always face the sun, which means power generation can be nearly continuous compared to the daily pattern on Earth,” says Wei He, senior lecturer in engineering at King’s College London and lead author of the study. “And, because it’s in space, the solar radiation is higher than on the Earth’s surface.”
The study examined two NASA-designed concepts. One, called the heliostat swarm, uses thousands of mirror-like reflectors to concentrate sunlight onto a central collector. This design (currently too ambitious for current tech) could deliver near-constant power with 99.7% annual availability. The second, a simpler planar array design, works more like a giant orbiting sheet of panels. It’s closer to being technically feasible but would only capture sunlight about 60% of the time.
When plugged into a model of Europe’s 2050 energy grid, the heliostat design emerged as a game-changer. It not only displaced massive amounts of wind and solar but also reduced the need for expensive batteries by more than 70%. “Space-based solar power is a potential technology and can provide continuous solar power as a renewable energy source,” He says.
Can this actually work?
Researchers say space panels will likely play an important role within two decades. But it won’t be easy. To get the power back to Earth, satellites would convert sunlight into microwaves and beam it down to vast receiving stations called rectennas. These ground stations, stretching several square kilometers, would then feed the electricity into the grid. The authors note that lightweight rectenna designs could allow some land co-use, but it’s not hard to imagine the public backlash against living next to a microwave beam.
Then there’s the orbital traffic jam. As He puts it during an interview with The Guardian: “There are some risks to consider, such as how the satellite in space could have too many solar panels. Could it cause collisions or be damaged by debris in space?”
The cost hurdles are even steeper. Right now, building and launching such systems is one to two orders of magnitude too expensive. For the heliostat design to make economic sense, its costs would need to drop to about 14 times the projected price of terrestrial solar by 2050. The planar array would need to fall to around 9 times that cost.
Despite these obstacles, the researchers argue that Europe has a unique advantage. The continent already runs one of the most integrated electricity grids in the world and has decades of experience with multinational space projects under the European Space Agency. That combination could make a joint SBSP venture not just possible but attractive.
“Now is the time,” He insists. The models suggest that by 2050, if costs drop as projected, space-based solar could displace not just fossil fuels but also much of the land-based renewable buildout. That means fewer wind turbines sprouting across landscapes, fewer solar farms carpeting fields, and less reliance on long-term battery banks.
Other nations are not waiting. Japan has already folded SBSP into its national energy and space strategy. China, India, Russia, and the U.S. are running their own programs. Europe risks falling behind if it hesitates.
Science fiction? Not for long
It’s easy to be skeptical. After all, the idea of giant solar stations in orbit still sounds like something that belongs in a Neal Stephenson novel. But the economics of space are changing fast. Reusable rockets are cutting launch costs. Orbital robotics are advancing. Even small-scale experiments in wireless power transmission have succeeded.
The study’s message is not that we should start building orbital power plants tomorrow. It’s that the time has come to take the idea seriously — to begin the experiments, set the policies, and test the risks. Because if the technology matures, the payoff could be enormous: a clean, constant power source that doesn’t care if the wind blows or the clouds roll in.
As the researchers write, space-based solar is no longer just a “blue-sky idea.” It might one day be the power plant that hangs above the sky itself.
The findings appeared in the journal Joule.
