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Emerging projects suggest technologies that could supply the grid, datacenters, and other energy-hungry facilities with electricity from space could be here within five years.
Credit: bombermoon / Getty Images
It has taken the best part of a century, but the notion of collecting the Sun’s energy in outer space and beaming it to collectors on Earth to generate electricity 24 hours a day—an idea hatched by science fiction author Isaac Asimov in 1940—is edging towards reality and could arrive early next decade.
The realization of viable space-based solar power (SBSP) systems has long been stymied by a lack of enabling technologies, but thanks to a clutch of successful ground and orbital power-beaming tests, and advances in reusable, heavy-lift rocketry and in-space assembly robots, entrepreneurs and nation-states alike now believe SBSP is becoming economically and technically possible, and a number of varied power-beaming-from-space projects are now in the planning.
Startup Overview Energy (Ashburn, VA), for example, in late April announced plans for a constellation of SBSP satellites that, sometime in 2030, will begin beaming a gigawatt of power to Meta’s AI datacenters. Unlike other SBSP approaches, Overview’s technology beams power from space to existing solar panels on the ground, using a near-infrared, laser-based power beaming technique that it is currently patenting. This choice of wavelength lends Overview an ability to deliver energy to solar panels at night, giving companies like Meta extra hours of solar power from terrestrial infrastructure that normally lies idle when the sun is not out.
“Under our agreement, Meta has 24/7 access to the beam capacity,” said Laura Wetzel, an Overview Energy representative. “Since they have a lot of solar projects in different places around the world, they’ll be able to use the beam somewhere at any given time.”
Overview Energy also has struck a deal with the U.S. Air Force to supply power from space to remote bases in Alaska and the Pacific.
British startup Space Solar (Harwell, Oxfordshire), for example, plans to beam between 200 kilowatts and several megawatts of power from space to an isolated science research base in the Antarctic. Said Sam Adlen, co-CEO of Space Solar, “Our current baseline plan sees the polar power project going live in six years, followed by a 30-megawatt system for Iceland, but in practice it will depend on how financing comes together.”
Speaking of demand, Adlen said, “As AI workloads surge and datacenters proliferate globally, electricity demand is growing at a pace that threatens to outstrip supply. So the race is on to secure energy which can accommodate AI’s exponential growth.” He said space-based solar power satellites can provide datacenters the “continuous, clean, and abundant source of power” they’ll need, as ground antennas can be built on top of them, allowing them to receive “low cost, reliable, continuous gigawatt scale power directly.”
In the U.S., a raft of startups are focused on SBSP. John Bucknell, CEO of Virtus Solis (Troy, MI), is planning a full end-to-end service for energy suppliers. “We’ll deliver complete power plants, including the inverters, grid connection, space launch, everything. As we look like a solar farm from a construction perspective, any solar developer can stand up a SBSP ground station,” Bucknell said.
Others have more focused SBSP ideas. Cowboy Space Corp. (San Carlos, CA), for instance, formerly called Aetherflux, is planning a system to provide on-demand, beamed power to remote military bases, to populations suffering sustained power outages after natural disasters, and to datacenters in space. Mantis Space (Albuquerque, NM), aims to beam power from orbit to light-starved satellites that are eclipsed in Earth’s shadow.
On top of these private sector ventures, China, Japan, and the U.K. are investigating SBSP technology with the aim of launching kilometer-scale satellites in the mid-2030s and beyond as a means of generating gigawatts of power to help reach net-zero-carbon targets by 2050. The 27-nation EU is also undertaking feasibility studies.
The broad idea behind most SBSP projects is to harvest solar power in outer space, rather than on Earth. Thanks to the day-night cycle, clouds, rain, and the vagaries of the seasons, even the biggest commercial solar farms sprawled across fields and deserts on Earth can only deliver intermittent power, while in space, SBSP systems are expected to deliver power continually, as long as they have technology to beam energy through Earth’s moisture-laden atmosphere.
In most SBSP architectures, the idea is that a satellite with kilometer-long solar arrays in geostationary orbit harvests gigawatts of solar energy 24/7 and transmits it, in the form of a safe, low-intensity microwave power beam, to a five-kilometer-wide ground antenna, which converts it to electricity for the grid. As microwave wavelengths are not absorbed by water, the power beam always reaches the ground antenna, whatever the weather.
Key to making this an efficient process has been the integration of the SBSP spacecraft’s solar panels with semiconductor microwave amplifiers, so the combination operates as one so-called “sandwich” module—with low losses compared to previous designs that fed electricity from the solar panels to separate microwave oscillators.
The ground antenna is formally known in SBSP circles as a “rectenna”—short for rectifying antenna—as its role is to receive the alternating microwave signal by inducing currents in an array of simple, cheap dipole antennas. Diodes then rectify the AC to direct current, and the DC signal is then used to energize inverters that produce AC at the local grid frequency.
Explained Space Solar’s Adlen, “These antennas are comprised of a transparent, mesh-like structure. They can be sited to enable crops to grow underneath, or allow areas to be re-wilded, or they can be sited over a terrestrial solar farm or datacenter. They take up about 40% of the land area of terrestrial solar for an equivalent energy output.”
The microwave beam, spread out over 5km, has only 25% of the power density of the midday Sun at the Equator, which SBSP proponents say presents no risk to people, animals, or vehicles passing through it.
Asimov described the broad idea of SBSP in the 1941 short story Reason, but gave no clues on how it might be accomplished.
In a 1968 Science article, Peter Glaser, head of engineering sciences at Arthur D. Little (Cambridge, MA), proposed the use of a microwave power beam as the weatherproof downlink for SBSP. While actually putting it into practice was infeasible in 1968, advances in technology have yielded thinner, increasingly efficient solar cells, semiconductor microwave amplifiers, solid-state phased array transmitters, and carbon fiber spacecraft construction that make SBSP possible.
On the energy transmission front, NASA in 1975 demonstrated power beaming with a 2.4-GHz microwave signal transmitted 1.5 kilometers through air, delivering 34 kilowatts to a receiver fitted with gallium arsenide semiconductor conversion circuits. In 2021, researchers at the U.S. Naval Research Laboratory successfully tested conversion of solar-derived electric power to microwaves in an experiment mounted on a U.S. Space Force spacecraft.
In 2023, an experiment successfully tested microwave beam generation and beam steering in space, using a system developed by a team at Caltech using phased array antennas. Caltech’s experiment also proved that a tension-loaded ultralight carbon-fiber structure designed to support solar panels and power beaming transmitters could self-deploy in orbit.
Recent developments in self-deploying large solar panel arrays by U.S.-based spaceflight contractor Redwire also look set to make SBSP satellites a feasible orbital build, as they unfurl themselves using stored strain energy in the material, rather than power-hungry motors.
SBSP proponents appear to have the hardware they need to ship and assemble in orbit kilometer-scale solar collecting and beaming spacecraft.
On the software side, autonomous guidance, navigation, and control algorithms will keep the spacecraft tracking the Sun so solar panels remain energized, but they will also have to securely seek out and lock onto ground antennas to steer power beams to them without spilling the signal outside them, wasting energy. Said Paul Jaffe, vice-president of systems engineering at Overview Energy, “We use a ground-based beacon the size of a shipping container to tell the satellite where to point, and coarse and fine tracking loops to home in on the receiver.”
Added Jaffe, who ran the SBSP orbital tests on the U.S. Space Force’s X-37B spaceplane for the U.S. Defense Department’s Naval Research Laboratory, “There might be a challenge in making our computing resources both extremely cheap and [space] radiation-tolerant for long periods of time, but any challenge in that area is probably negligible compared to doing the same for the photovoltaics in orbit.”
What is the timeline for an active SBSP system? Space Solar plans to beam microwave power to the Rothera Research Station on Adelaide Island on the Antarctic Peninsula in the early 2030s. The hope is that Space Solar’s SBSP satellite, which will have 20,000 solar panel layers arranged in a helix, with a large solar reflector capping each end of a DNA-like spiral, will provide the base with a sustainable source of power, at least 200 kilowatts of electricity, possibly more.
If the Iceland installation works as planned, Space Solar will build a bigger satellite to feed a ground antenna 1.5 kilometers across with 30 megawatts of electricity for Reykjavik Energy. Both the Antarctic and Icelandic satellites will only deliver intermittent power because the elliptical orbits needed to reach their respective northern and southerly latitudes mean the satellites will only dwell over their targets for a few hours a day. Space Solar says that will be enough to charge batteries until the next orbital pass.
Overview Energy plans to beam near-infrared laser light to standard terrestrial solar farms. The company will offer power producers running conventional ground-based solar farms the ability to enable their arrays to continue to capture energy after the sun sets, since a gap in the atmosphere’s water absorption spectrum allows a small range of near-infrared wavelengths to cut through the moisture unharmed.
Cowboy Space has noticed this as well. The company is planning to beam energy from low Earth orbit SBSP satellites via near-infrared lasers to circa-10-meter-diameter ground receivers at military bases in remote areas where it is risky to deliver fuel, and also in disaster zones where hospitals, first-responder organizations, and cellphone networks need power.
Earth is not the only target for SBSP. Just as Mantis Space plans to beam laser light to satellites in the dark of Earth’s shadow to keep them powered up, an infrared-laser SBSP project in the works from Volta Space Technologies is targeting the Moon. During the two-week-long lunar night, temperatures plummet to minus 130 Celsius (-202 degrees F), which can embrittle and fracture batteries and critical electronic systems. Volta is planning a constellation of SBSP satellites in lunar orbit that will beam power to warm the electronics of lunar rovers, landers, and surface science equipment to help them survive the lunar night.
During an interview on Late Night with David Letterman in October 1980, Asimov took credit for inventing space-based solar power, and hinted at a lunar offshoot: “I talked about space stations getting energy down to Earth in 1940 and I got that almost right, but I put it in Mercury’s orbit, instead of the Moon’s orbit, to get it closer to the Sun. But maybe someday we’ll do that.”
AS SBSP PREPARES FOR LIFTOFF, SATELLITE
CONGESTION PRESENTS POTENTIAL THREATS
Plans for Space-Based Solar Power (SBSP) satellites are being laid at an exceptionally challenging time in the history of spaceflight, as Earth orbits are becoming ever more dangerously congested with satellites thanks to the advent of the “megaconstellations” that now deliver broadband Internet to digitally underserved, remote areas from low Earth orbit. California-based SpaceX, a pioneer of this technology, has in the last five years launched 10,000 of the 42,000 satellites it says its Starlink orbital Internet service will ultimately require. That has increased the orbital population from 4,000 satellites five years ago to 14,000 today.
Starlink’s success has prompted commercial and nation-state rivals, such as Amazon, OneWeb, and the Chinese government, to plan their own large orbital Internet constellations—to the extent that the regulator, the UN’s International Telecommunication Union, says spaceflight operators have now applied to launch no less than 1.7 million satellites by 2030. This is regarded as unsustainable by astronomers at the European Southern Observatory, which has said that such numbers will have “devastating consequences.”
It does not end at broadband provision, however. On top of the orbital Internet, firms such as SpaceX, and startups Starcloud (Redmond, WA) and Orbital Compute (Los Angeles, CA), are planning to evade the power demands of datacenters on Earth by launching millions of small GPU compute clusters into orbit on what SpaceX founder Elon Musk called ‘AI satellites’. Each spacecraft alone does not pack much compute power, but by using laser links to connect them with other AI satellites, they might collectively be able to offer datacenter-like performance on inference tasks. Once again, the spacecraft numbers here are very high: SpaceX wants to fly 1 million AI satellites, Starcloud 88,000, and Orbital Compute 100,000.
Such vast satellite numbers raise a litany of so-far unresolved issues. First, they threaten the dark skies that optical astronomers need to scan the heavens, not least for potential incoming near-Earth asteroids. Second, the radio signals from these satellites can interfere with radio astronomy, too. Third, the end-of-life reentry of these satellites (they run out of fuel after five years) deposits aluminum oxide in the upper atmosphere which, ongoing research suggests, could deplete Earth’s radiation-protective ozone layer. Fourth, the reentries present a threat to civil aviation, as debris could strike pressurized aircraft if a falling satellite does not burn up completely.
A fifth issue—possibly the space industry’s biggest fear related to having millions of satellites packed into low Earth orbits below 2,000 kilometers—is a runaway phenomenon called Kessler Syndrome. Named after a former NASA engineer, Don Kessler, who in 1978 predicted what could happen when a satellite in an overly-packed orbit suffers a failure and collides with another, or simply suffers an in-orbit breakup, perhaps due to a fuel tank explosion. This, Kessler predicted, would create a blizzard of space debris, which could then strike other satellites, creating a collision cascade in which more and more debris is created in a chain reaction that could leave low Earth orbit an unnavigable scrapyard of hypersonic metal, threatening not only commercial satellite operations but also the lives of astronauts in crewed spacecraft and space stations.
Research is ongoing into mitigating the threat to dark skies, reentry ozone depletion, civil aviation risks and the space situational awareness that could limit Kessler Syndrome risks, but whether regulation can be put in place in time in remains to be seen.—Paul Marks
Paul Marks is a technology, aviation, and spaceflight journalist, writer, and editor based in London, U.K.
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Emerging projects suggest technologies that could supply the grid, datacenters, and other energy-hungry facilities with electricity from space could be here within five years.
It’s taken the best part of a century, but the notion of collecting the Sun’s energy in outer space and beaming it to collectors on Earth to generate electricity 24 hours a day—an idea hatched by science fiction author Isaac Asimov in 1940—is edging towards reality and could arrive early next decade.
The fruition of space-based solar power (SBSP) has long been stymied by a lack of enabling technologies, but thanks to a clutch of successful ground and orbital power-beaming tests, and advances in reusable, heavy-lift rocketry and in-space assembly robots, entrepreneurs and nation-states now believe SBSP is becoming economically and technically possible, and a number of varied power-beaming-from-space projects are now in the planning.
Startup Overview Energy (Ashburn, VA), for example, in late April announced plans for a constellation of SBSP satellites that, sometime in 2030, will begin beaming a gigawatt of power to Meta’s AI datacenters. Unlike other SBSP approaches, Overview’s technology beams power from space to existing solar panels on the ground, using a near-infrared, laser-based power beaming technique that it is currently patenting. This choice of wavelength lends Overview an ability to deliver energy to solar panels at night, giving companies like Meta extra hours of solar power from terrestrial infrastructure that normally lies idle when the sun is not out.
“Under our agreement, Meta has 24/7 access to the beam capacity,” said Laura Wetzel, an Overview Energy representative. “Since they have a lot of solar projects in different places around the world, they’ll be able to use the beam somewhere at any given time.”
Overview Energy also has struck a deal with the U.S. Air Force to supply power from space to remote bases in Alaska and the Pacific.
British startup Space Solar (Harwell, Oxfordshire), for example, plans to beam between 200 kilowatts and several megawatts of power from space to an isolated science research base in the Antarctic. Said Sam Adlen, co-CEO of Space Solar, “Our current baseline plan sees the polar power project going live in six years, followed by a 30-megawatt system for Iceland, but in practice it will depend on how financing comes together.”
Speaking of demand, Adlen said, “As AI workloads surge and datacenters proliferate globally, electricity demand is growing at a pace that threatens to outstrip supply. So the race is on to secure energy which can accommodate AI’s exponential growth.” He said space-based solar power satellites can provide datacenters the “continuous, clean, and abundant source of power” they’ll need, as ground antennas can be built on top of them, allowing them to receive “low cost, reliable, continuous gigawatt scale power directly.”
In the U.S., a raft of startups are focused on SBSP. John Bucknell, CEO of Virtus Solis (Troy, MI), is planning a full end-to-end service for energy suppliers. “We’ll deliver complete power plants, including the inverters, grid connection, space launch, everything. As we look like a solar farm from a construction perspective, any solar developer can stand up a SBSP ground station,” Bucknell said.
Others have more focused SBSP ideas. Cowboy Space Corp. (San Carlos, CA), for instance, formerly called Aetherflux, is planning a system to provide on-demand, beamed power to remote military bases, to populations suffering sustained power outages after natural disasters, and to datacenters in space. Mantis Space (Albuquerque, NM), aims to beam power from orbit to light-starved satellites that are eclipsed in Earth’s shadow.
On top of these private sector ventures, China, Japan and the United Kingdom are investigating SBSP technology with the aim of launching kilometer-scale satellites in the mid-2030s and beyond as a means of generating gigawatts of power to help reach net-zero-carbon targets by 2050. The 27-nation EU is also undertaking feasibility studies.
Why Use Space-Based Solar Power?
The broad idea behind most SBSP projects is to harvest solar power in outer space, rather than on Earth. Thanks to the day-night cycle, clouds, rain, and the vagaries of the seasons, even the biggest commercial solar farms sprawled across fields and deserts on Earth can only deliver intermittent power, while in space, SBSP systems are expected to deliver power continually, as long as they have technology to beam energy through Earth’s moisture-laden atmosphere.
In most SBSP architectures, the idea is that a satellite with kilometer-long solar arrays in geostationary orbit harvests gigawatts of solar energy 24/7 and transmits it, in the form of a safe, low-intensity microwave power beam, to a five-kilometer-wide ground antenna, which converts it to electricity for the grid. As microwave wavelengths are not absorbed by water, the power beam always reaches the ground antenna, whatever the weather.
Explained Space Solar’s Adlen, “These antennas are comprised of a transparent, mesh-like structure. They can be sited to enable crops to grow underneath, or allow areas to be re-wilded, or they can be sited over a terrestrial solar farm or datacenter. They take up about 40% of the land area of terrestrial solar for an equivalent energy output.”
The microwave beam, spread out over 5km, has only 25% of the power density of the midday Sun at the Equator, which SBSP proponents say presents no risk to people, animals, or vehicles passing through it.
SBSP’s Multi-Decade Technological Evolution
Asimov described the broad idea of SBSP in a 1941 short story “Reason,” but gave no clues on how it might be accomplished.
In a 1968 Science article, Peter Glaser, head of engineering sciences at Arthur D. Little (Cambridge, MA), proposed the use of a microwave power beam as the weatherproof downlink for SBSP. While actually putting it into practice was infeasible in 1968, advances in technology have yielded thinner, increasingly efficient solar cells, semiconductor microwave amplifiers, solid-state phased array transmitters, and carbon fiber spacecraft construction that make SBSP possible.
On the energy transmission front, NASA in 1975 demonstrated power beaming with a 2.4-GHz microwave signal transmitted 1.5 kilometers through air, delivering 34 kilowatts to a receiver fitted with gallium arsenide semiconductor conversion circuits. In 2021, researchers at the U.S. Naval Research Laboratory successfully tested conversion of solar-derived electric power to microwaves in an experiment mounted on a U.S. Space Force spacecraft.
In 2023, an experiment successfully tested microwave beam generation and beam steering in space, using a system developed by a team at Caltech using phased array antennas. Caltech’s experiment also proved that a tension-loaded ultralight carbon-fiber structure designed to support solar panels and power beaming transmitters could self-deploy in orbit.
Recent developments in self-deploying large solar panel arrays by U.S.-based spaceflight contractor Redwire also look set to make SBSP satellites a feasible orbital build, as they unfurl themselves using stored strain energy in the material, rather than power-hungry motors.
SBSP proponents appear to have the hardware they need to ship and assemble in orbit kilometer-scale solar collecting and beaming spacecraft.
On the software side, autonomous guidance, navigation, and control algorithms will keep the spacecraft tracking the Sun so solar panels remain energized, but they will also have to securely seek out and lock onto ground antennas to steer power beams to them without spilling the signal outside them, wasting energy. Said Paul Jaffe, vice-president of systems engineering at Overview Energy, “We use a ground-based beacon the size of a shipping container to tell the satellite where to point, and coarse and fine tracking loops to home in on the receiver.”
Added Jaffe, who ran the SBSP orbital tests on the U.S. Space Force’s X-37B spaceplane for the U.S. Defense Department’s Naval Research Laboratory, “There might be a challenge in making our computing resources both extremely cheap and [space] radiation-tolerant for long periods of time, but any challenge in that area is probably negligible compared to doing the same for the photovoltaics in orbit.”
First Light for SBSP
What is the timeline for an active SBSP system? Space Solar plans to beam microwave power to the Rothera Research Station on Adelaide Island on the Antarctic Peninsula in the early 2030s. The hope is that Space Solar’s SBSP satellite, which will have 20,000 solar panel layers arranged in a helix, with a large solar reflector capping each end of a DNA-like spiral, will provide the base with a sustainable source of power, at least 200 kilowatts of electricity, possibly more.
If the Iceland installation works as planned, Space Solar will build a bigger satellite to feed a ground antenna 1.5 kilometers across with 30 megawatts of electricity for Reykjavik Energy. Both the Antarctic and Icelandic satellites will only deliver intermittent power because the elliptical orbits needed to reach their respective northern and southerly latitudes mean the satellites will only dwell over their targets for a few hours a day. Space Solar says that will be enough to charge batteries until the next orbital pass.
Overview Energy plans to beam near-infrared laser light to standard terrestrial solar farms. The company will offer power producers running conventional ground-based solar farms the ability to enable their arrays to continue to capture energy after the sun sets, since a gap in the atmosphere’s water absorption spectrum allows a small range of near-infrared wavelengths to cut through the moisture unharmed.
Cowboy Space has noticed this as well. The company is planning to beam energy from low Earth orbit SBSP satellites via near-infrared lasers to circa-10-meter-diameter ground receivers at military bases in remote areas where it is risky to deliver fuel, and also in disaster zones where hospitals, first-responder organizations, and cellphone networks need power.
Space-to-Space Energy
Earth is not the only target for SBSP. Just as Mantis Space plans to beam laser light to satellites in the dark of Earth’s shadow to keep them powered up, an infrared-laser SBSP project in the works from Volta Space Technologies is targeting the Moon. During the two-week-long lunar night, temperatures plummet to minus 130 Celsius (-202 degrees F), which can embrittle and fracture batteries and critical electronic systems. Volta is planning a constellation of SBSP satellites in lunar orbit that will beam power to warm the electronics of lunar rovers, landers, and surface science equipment to help them survive the lunar night.
During an interview on Late Night with David Letterman in October 1980, Asimov took credit for inventing space-based solar power, and hinted at a lunar offshoot: “I talked about space stations getting energy down to Earth in 1940 and I got that almost right, but I put it in Mercury’s orbit, instead of the Moon’s orbit, to get it closer to the Sun. But maybe someday we’ll do that.”
Paul Marks is a technology, aviation, and spaceflight journalist, writer, and editor based in London, U.K.
Submit an Article to CACM
CACM welcomes unsolicited submissions on topics of relevance and value to the computing community.
You Just Read
© 2026 ACM 0001-0782/26/5
News
Space-Based Solar Power Is On Its Way
Architecture and Hardware
News
Testing Asimov’s Idea for Power From Space
Architecture and Hardware
News
Solar Energy Turns a New Leaf
Architecture and Hardware
News
In Space, No One Can Fix Your Sign Errors
Architecture and Hardware
Advertisement
Advertisement
LLMs Make Mathematics Easier. Now Raise the Bar
AI Monitoring of Animals Gets Wild
The Code Optimization Flywheel Won’t Spin Itself
ACM encourages its members to take a direct hand in shaping the future of the association. There are more ways than ever to get involved.
By opening CACM to the world, we hope to increase engagement among the broader computer science community and encourage non-members to discover the rich resources ACM has to offer.
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