In space, as one Caltech researcher put it, it’s “always noon on a sunny day.”
The basic idea isn’t new—space-based solar power was mentioned in a sci-fi story in 1941, and NASA began studying it in the 1970s. Historically, it hasn’t been financially feasible. But some engineers working on the technology believe that has now changed.
“More than 50 years ago, the physics were proved out,” says Ed Tate, cofounder and chief technology officer at Virtus Solis, an early-stage startup that announced today that it aims to pilot its space-based solar tech in orbit in 2027. “In the past couple of years, the engineering has been accepted as being possible. The real transition here is the economics—we think that now, with all the trends that are there, that the economics are viable.”
The company plans to put solar panels in medium Earth orbit, and then use robots to automatically assemble them into large arrays—ultimately, hundreds of thousands of satellites connected together like Lego blocks. Each hexagonal satellite, around five feet wide, has built-in solar panels on one side, electronics in the middle, and antennas on the other side. Instead of moving the power through electrons in wires, it would be sent back to Earth using photons in a beam of invisible light. “We take the sunlight and we convert it into radio frequency beams,” says Tate. “The beams then are transmitted very narrowly to a target on the ground.”
It’s safe, the company says, because the intensity is far less than sunlight, and the beam would target a point that’s fenced off on the ground. (Still, it’s not clear whether it might be hard to get public acceptance; conspiracy theorists already blamed the 2018 California wildfires on “space lasers” that didn’t yet exist.)
The company has already demonstrated the wireless power transfer on the ground, using a receiver across the length of a football field. Next, it will be building prototype satellites and testing them on the ground to validate that they work together in the way that models predict. In a partnership with another startup called Orbital Robotics, it then plans to test a system for robotic assembly in space. The 2027 pilot is designed to be small, sending just a kilowatt of power back to Earth. But by 2030, the startup hopes to have its first commercial system in orbit. The first full system will be hundreds of feet wide, sending power to even larger receivers on the ground. Then the power will be converted to DC power and sent into the grid or used directly at sites like data centers or green hydrogen factories.
The system is more efficient than building out solar power and transmission infrastructure on Earth, Tate says. “Building a space-based solar power plant, we can move power from one end of the continent to the other because we’re just making a small change of where the beam goes,” he says. “And we use about as much material to move from one end of the continent to the other as if you need to move about 100 miles on the ground. That’s a massive savings in what you need to commit to infrastructure and what you need to commit to resources to make it work.”
A recent NASA report argued that space-based solar tech still isn’t commercially viable, though the startup says the report’s assumptions about cost are outdated. The cost of satellite launches has steeply dropped and will drop further. Robotic assembly is possible. “Robotics completely changes the equations and drops the cost radically for building anything in space,” says Tate. The technology for wireless energy transfer has also fallen in cost. Because the system is efficient, at a large scale, the company believes that it will be cheaper than solar on the ground.
Others are working toward the same goal, including Space Solar, a company in the U.K. Solaris, a program run by the European Space Agency, is studying the technology and plans to put out a report about the feasibility next year. Japan aims to build a solar power system in space as early as next year. The Chinese government plans to demonstrate the tech in 2028. At Caltech, where researchers have been developing a version of the technology for a decade, a prototype sent into space last year sent a tiny amount of energy back to the team’s lab in Pasadena.
It’s still too early to predict whether large projects will succeed. But the potential is huge: If it can commercialize, it could theoretically scale up to provide all of the power that humans need.
According to fastcompany.com
