Solar power has an unavoidable weakness: it can't generate electricity at night, it's at the mercy of weather, and it faces grid congestion barriers. Space-based solar power aims to overcome these limits with the idea of "generating power continuously in orbit and beaming it wirelessly to wherever it's needed on the ground." Following a panel discussion held in San Francisco in April 2026, this concept has begun moving toward concrete contract talks.
Virtus Solis revealed it had signed contract terms, Overview Energy disclosed a capacity reservation agreement with Meta, and Reach Power described its ground-based operational deployment along with a 2027 NASA demonstration plan—according to a PowerMag report dated July 9, 2026. However, an independent NASA estimate shows a roughly 20-fold variation depending on the assumptions used. The ambitious targets the industry cites barely align with the most optimistic end of that estimate.
At SF Climate Week 2026, three companies moved toward the commercial phase
Three different types of progress—500MW, 1GW, and already-implemented ground-based wireless power transmission—were discussed at "Energy from Space," an event held in San Francisco on April 21, 2026. The panel, part of SF Climate Week 2026, was co-hosted by the YPE (Young Professionals in Energy) SF Bay Area chapter and the Space Frontier Foundation, with sponsorship from Reach Power. Speakers included Virtus Solis CEO John Bucknell, Overview Energy CCO Abdullah Al-Shakarchi, and Reach Power CEO Chris Davlantes. PowerMag reported on this content on July 9, 2026.
Bucknell, a former SpaceX engineer, said that for the initial deployment contract for space-based solar power (SBSP), his company had signed terms for a 500MW-scale agreement. While the counterparty and financial details were not disclosed, the company aims to begin pilot operations within 24 months. Six days after the panel, on April 27, Overview Energy officially announced a capacity reservation agreement with Meta for up to 1GW. The plan calls for an in-orbit demonstration in 2028 and the start of commercial supply in 2030.
What Reach Power described was progress of a different nature from the other two companies. The company's ground-based wireless power transmission system is already operational, with the Department of Defense as an actual customer for robotics, defense, and remote-operation applications. As for orbital space-based solar power, the company is at the stage of planning a relay satellite launch with NASA in 2027, and has not yet signed commercial supply contracts like those of Virtus Solis or Overview Energy.
The fact that three distinct types of progress—signed contract terms for 500MW, a 1GW capacity reservation, and already-implemented ground-based wireless power transmission—were discussed on the same stage is itself a sign that this field is moving beyond a purely demonstration-focused stage. However, the "weight" of these contracts is not uniform. The most concrete official announcement is Overview Energy's capacity reservation agreement with Meta for up to 1GW (which grants early access rights and is explicitly described as not being a final power supply contract), while Virtus Solis leads in signed contract terms and Reach Power leads in commercializing ground-based technology.
How satellites send power to the ground
The basic principle of space-based solar power is simple. By placing a satellite equipped with unfurled solar panels in Earth orbit—choosing an orbit that minimizes time in Earth's shadow—it can keep generating power with almost no effect from the atmosphere, clouds, or nighttime darkness. However, even in NASA's reference designs, the annual hours of possible power generation vary by design approach, and it is not the case that generation is uninterrupted regardless of which method is used. While ground-based solar panels see large output fluctuations depending on weather even during daylight hours, the advantage in orbit is that sunlight can be received almost continuously and stably.
The generated electricity is converted into microwaves or lasers and transmitted wirelessly to a ground-based receiving facility. In November 2025, Overview Energy succeeded in a demonstration transmitting power from a laser oscillator mounted on a Cessna Caravan flying at an altitude of 5,000 meters to a fixed solar cell on the ground, becoming one of the few cases confirming power transmission technology from a moving transmission source to the ground using an actual flight vehicle. On the ground side, microwave receiving antennas called "rectennas" are laid out across a large plot of land, converting the received radio waves into electricity and feeding it into the power grid. This receiving facility is said to span several kilometers in scale, making it as much of a construction hurdle as the power-generating satellite itself.
The land area required for the ground receiving facility is expected to be comparable in size to a solar power plant of similar scale. In addition to satellite launches, the cost of securing land and constructing the receiving side must also be factored into business plans. Microwaves and lasers each have their own advantages and disadvantages: lasers offer high directionality and allow for tightly focused beams, but are more susceptible to attenuation from the atmosphere and clouds. The reason Overview Energy chose a laser for its Cessna demonstration appears to be to leverage this high directionality in verifying precision power transmission control.
Overview Energy's Al-Shakarchi explained the advantage of this approach at the panel as follows: "The real power of space-based solar power lies in being able to switch transmission destinations geographically. A single satellite can dynamically transmit power to San Francisco, Santiago, Spain, and Texas." The idea is that even if a ground grid is congested or disaster-stricken, the same satellite can redirect power to a different receiving site—a flexibility that fixed ground-based power plants don't have.
NASA's estimates showed more than a 20-fold variation
Despite the momentum behind these contracts, the numbers representing actual costs paint very different pictures depending on whether you look at the industry or at NASA. According to PowerMag, the space-based solar power industry's overall LCOE (Levelized Cost of Energy—a metric that averages the total cost of building, operating, and decommissioning a power facility across its generation output, converted to a per-kilowatt-hour unit price) target is around $50-100/MWh. Meanwhile, an independent estimate compiled by NASA's Office of Technology, Policy, and Strategy (OTPS) in January 2024 shows results that vary surprisingly widely depending on the assumptions.
The NASA OTPS report calculates multiple scenarios for two types of reference designs: an innovative deployable heliostat swarm and a mature planar array. Under a baseline scenario extrapolating current technology, the LCOE is $0.61-1.59/kWh ($610-1,590/MWh). In a sensitivity analysis that varies conditions such as launch cost one at a time, this drops to $0.20-0.50/kWh ($200-500/MWh). And in a combined scenario meeting all six conditions—launch cost of $50 million per flight, solar cell efficiency of 50%, lower-cost servicing/debris-removal vehicles, learning-curve improvements from mass production, equipment lifespan of 15 years, and orbital repositioning via electric propulsion—the LCOE drops to $0.03-0.08/kWh ($30-80/MWh). Comparing the baseline and combined scenarios within the same design, there is roughly a 20-fold difference (0.61÷0.03) for the innovative deployable heliostat swarm and roughly a 20-fold difference (1.59÷0.08) for the mature planar array.
The level closest to the industry's stated $50-100/MWh target is this combined scenario's $30-80/MWh range. In other words, the industry's target is not a figure that NASA dismisses as fantasy, but rather sits within the best-case scenario that NASA itself acknowledges is achievable only "if all six conditions are met." The focus now shifts to how realistic it actually is, today, to bring down these six conditions—particularly launch cost—to around $50 million per flight. As a point of comparison, the NASA report also cites NREL's projected 2050 LCOE for ground-based renewable energy (geothermal, hydropower, solar-plus-storage, onshore wind) and nuclear power, at $0.02-0.05/kWh ($20-50/MWh)—leaving open the possibility that even if the combined scenario is realized, it may not be cheaper than this benchmark.
There is also a point of comparison regarding transmission efficiency. NASA's report explicitly states, for its own reference design, efficiencies for the segment from the satellite's emitted energy to its arrival at the ground receiving facility: 90% antenna radiation efficiency, 98% atmospheric transmission efficiency, and 95% beam capture efficiency—which together multiply to approximately 84%. The 85% transmission efficiency that Bucknell cited at the panel appears to refer to this same segment, putting it at roughly the same level as NASA's assumptions. However, the overall efficiency—including the satellite's internal DC-RF conversion (assumed at 70% in NASA's premise) and the ground-side DC conversion—is a separate figure. Since Virtus Solis uses its own proprietary satellite design, a simple comparison isn't possible, and no independent verification of this figure currently exists. For now, the enthusiasm behind these contracts and the scrutiny of the underlying numbers are proceeding at different speeds.
Nearly 60 years after it was first proposed in 1968, why now?
The concept of space-based solar power itself is not new. Aerospace engineer Peter Glaser first proposed it in the journal Science in 1968, and in the 1970s NASA and the Department of Energy jointly studied its feasibility. Documents from that era stated that for the concept to be economically viable, launch costs would need to be kept below $50 per kilogram, and estimated that operating a dedicated heavy-lift launch vehicle (HLLV) for 300 flights could bring costs down to about $30 (in 1979 dollars). However, the uncertainty around transportation costs was significant, and even that same document did not draw a definitive conclusion on profitability.
Yet that same document estimated the launch cost using the Space Shuttle—then under development—at $850 per kilogram, a gap of 17 to 28 times compared to the $30-50 assumed for a dedicated rocket. The economics of SPS (Solar Power Satellites) depended on a dedicated heavy-lift rocket, but that rocket was never built, and the concept remained stuck at the research level for nearly half a century.
The tide turned in 2023, when Caltech's orbital demonstration mission SSPD-1 succeeded in transmitting microwave power in orbit. The solar cell performance evaluation (ALBA) and microwave wireless power transmission (MAPLE) were separate payloads, with power supplied from the host satellite—meaning it was not an integrated demonstration combining generation and transmission. Some deployment mechanisms also malfunctioned, so the demonstration cannot be called a complete success. Still, achieving the world's first successful orbital microwave wireless power transmission carries major significance. In less than three years since that demonstration, three U.S. startups have simultaneously reached the stage of discussing contracts and demonstration plans.
The biggest factor behind this decades-stalled concept suddenly moving forward in recent years is the drop in launch costs enabled by the practical realization of reusable rockets. The level assumed in 1970s estimates—"$30-50 per kg with a dedicated rocket"—has still not itself been achieved. But the emergence of reusable rockets has lowered the cost of actual, available launch means, and this is what underpins the current contract-driven momentum.
Japan's JAXA and METI are also moving, but targets are not aligned uniformly
Japan's public and private sectors are also in motion. The Japan Space Systems (JSS), a general incorporated foundation supported by the Ministry of Economy, Trade and Industry (METI), plans to conduct a demonstration of a ground receiving facility within fiscal year 2026, aiming to be the first such demonstration in the world.
However, Japan's targets are not monolithic. In a 2011 technical report, Mitsubishi Heavy Industries set a goal of achieving commercial operation of a 400MW-class system—equivalent to a single thermal power plant—around 2030. This is a technical document from 15 years ago, and it cannot be confirmed whether this target is still maintained as part of a current roadmap. Meanwhile, JAXA had previously presented estimates for achieving a 1GW-class system in the 2030s at a supply cost of ¥8 per kilowatt-hour, but the agency has now pushed back its realization target to "the latter half of the 21st century or beyond" and states it is no longer producing such cost estimates.
Converting that past estimate of ¥8/kWh at ¥150 to the dollar (as of July 2026) yields the equivalent of $53/MWh—a figure that, even back then, was close to the $50-100/MWh range the industry cites today. But since JAXA no longer presents this estimate itself, this conversion should be treated only as a reference point.
While U.S. startups push forward aggressively through contracts, Japan's public institutions have instead revised their own outlooks in a more cautious direction. Domestic research institutions, including JAXA, have a long track record in microwave transmission component technologies, having repeatedly verified transmission efficiency at the ground-experiment level even before Caltech's demonstration. The ground receiving facility demonstration JSS plans for fiscal year 2026 represents a step toward bringing this accumulated knowledge closer to the implementation stage.
Three conditions that must be met before this becomes reality
Whether space-based solar power transitions from concept to business hinges on whether three conditions are met simultaneously. The first is a further reduction in launch costs. How close actual launch expenses can get to the "$50 million per flight" level assumed in NASA's combined scenario will be the first hurdle.
The second is assembly technology for large structures in orbit—whether Virtus Solis and Overview Energy can solve, at full scale, the deployment mechanism challenges revealed by Caltech's demonstration. The third is third-party verification of overall transmission efficiency, including internal DC-RF conversion within the satellite—whether the 85% figure Bucknell cited remains merely a claim about the beam transmission segment, or whether it holds up even when DC-RF conversion losses are included, as determined through independent institutional measurement. If even one of these three conditions—launch cost, assembly technology, and overall transmission efficiency—remains unresolved, supply commensurate with the contracts will not begin.
Overview Energy's planned 2028 orbital demonstration and Reach Power's planned 2027 relay satellite launch with NASA represent, at minimum, the first opportunities related to on-the-ground verification of transmission efficiency. Neither company's announcements include descriptions of testing large-structure assembly in orbit within their scope, so it remains unclear for now when this challenge will actually be tested. The ground receiving demonstration JSS plans for fiscal year 2026 also occupies the same corner of transmission efficiency verification. Once measured data from these efforts comes together, it will finally become possible to judge numerically whether the industry's targets truly reach NASA's combined scenario, or whether they remain closer to the high costs of the baseline scenario.
Looking only at the number of contracts, space-based solar power is already in its commercialization phase. But the unit prices at which the 500MW and 1GW contracts were signed have not been disclosed, and whether those prices are closer to NASA's combined scenario ($30-80/MWh) or its baseline scenario ($610-1,590/MWh) is a question that the demonstration results planned between 2026 and 2028 will answer.