As grids race to decarbonize, a bold idea is returning with renewed credibility: capturing sunlight in space and sending it to Earth as microwaves. In 2026, space-based solar power is being studied by space agencies, utilities, and start-ups as a way to deliver clean, around-the-clock power, and microwave wireless power transfer sits at the heart of almost every proposed architecture. What once sounded like science fiction now has working prototypes in orbit and detailed techno-economic models suggesting that, under the right conditions, it could become a significant pillar of renewable energy systems.

Space-Based Solar Power Comes Of Age

The physics case for space solar is straightforward. In geostationary orbit, solar arrays receive nearly continuous sunlight, unbroken by night or clouds. Satellites can convert that light into DC power, feed it into a phased-array transmitter, and beam microwaves to a ground rectenna, which reconverts the energy into electricity for the grid. Recent analyses show that such systems could, in principle, deliver large amounts of firm renewable power with lower variability than wind and ground solar.Wjarr

The last several years have produced concrete milestones. The Caltech SSPD-1 mission demonstrated that a lightweight modular spacecraft could transmit power in space and send a detectable microwave beam to Earth, closing key technology gaps in phased-array control, power conversion, and in-space verification. California Institute of Technology+1 NASA’s 2024 space solar report documents parallel work by the U.S. Naval Research Laboratory and international partners, including in-space power beaming tests and high-fidelity simulations of orbital power satellites.NASA

In Europe and the United Kingdom, public agencies and start-ups are investing heavily. A study led by King’s College London suggests that if NASA-style space solar systems were integrated into Europe’s grid, they could ultimately supply a large share of renewable electricity while reducing overall system costs and storage requirements, assuming launch and hardware costs continue to fall. The Guardian UK-based Space Solar, meanwhile, has completed engineering design and Harrier demonstrator trials for a modular microwave power-beaming system, including a 360-degree steerable RF beam intended for future orbital platforms.

Why Microwaves Dominate The Architecture

Space solar concepts usually consider three options for transmitting power: microwaves, millimeter waves, or lasers. Recent technical assessments conclude that microwave transmission remains the most mature and robust option for large-scale space-to-Earth systems, largely because it combines reasonably compact antennas with low atmospheric attenuation and established safety models.Wjarr

At typical design frequencies around 2.45 GHz or 5.8 GHz, beams can penetrate clouds and heavy rain with only a few percent loss, and decades of rectenna research provide a strong foundation for building large receiving arrays with high RF-to-DC efficiency. Cambridge University Press & Assessment These rectenna farms would likely resemble low-rise fields of metal elements and diodes, with power densities at ground level kept comparable to or lower than midday sunlight.

Microwaves also benefit from modularity. Phased arrays made of many identical tiles can be manufactured at scale and launched in pieces, then assembled robotically in orbit. Individual modules can be switched off or reconfigured without compromising the rest of the aperture, making maintenance and upgradability far easier than monolithic systems.NASA

Economics, Use Cases And Military Interest

For now, the economics of space-based solar power are challenging. Launch costs, in-space assembly, and the expense of building gigawatt-class antenna arrays keep levelized costs high in most models. However, forward-looking analyses highlight specific applications where early SBSP systems could be competitive even at premium prices: remote mining operations, isolated communities, disaster zones, or defense installations where shipping fuel is expensive or risky.NASA

Defense organizations are taking notice for additional reasons. Persistent power beaming from orbit could keep surveillance drones or high-altitude platforms aloft, extend mission duration for electric aircraft, or supply temporary power to forward bases without fuel convoys. This dual-use potential raises complex geopolitical and regulatory questions but also accelerates funding and early deployment opportunities.NASA Technical Reports Server

Safety, Governance And Public Perception

Space-to-Earth microwave beams pose unique governance challenges. Even when designed with low power densities and multiple shutoff mechanisms, they occupy spectrum, cross borders, and raise questions about health and security. Existing RF exposure standards such as IEEE C95.1 and national guidelines provide a starting point, but regulators will need new frameworks for orbital power infrastructure, including coordination with aviation, satellite operators, and local authorities under the beam footprint.Kolegite+2Federal Communications Commission

Public acceptance will likely hinge on transparent risk communication and inclusive international governance. Space-based solar power, like undersea cables and global satellite constellations, could become a transnational critical infrastructure. That implies multinational ownership structures, shared standards, and dispute-resolution mechanisms, particularly if power beams can be redirected between countries in response to demand.NASA

Closing Thoughts And Looking Forward

In 2026, space-based solar power remains an audacious vision rather than a commercial reality, but microwave WPT has given it a technical backbone that earlier generations lacked. Successful in-orbit demonstrations, ground-based 360-degree beaming tests, and detailed energy-system modeling are turning a once speculative idea into a serious option on the table for governments facing decarbonization deadlines and energy security concerns.

The next decade will be defined by pilot projects: larger in-space demonstrators, ground rectenna test sites, and perhaps the first small-scale SBSP plants serving remote customers. If launch prices continue to decline and phased-array manufacturing scales, the economics may converge more quickly than skeptics expect. Microwave WPT is central to that trajectory, translating sunlight harvested in orbit into controllable power flows on Earth. Whether SBSP ultimately becomes a dominant energy source or a specialized complement, its development will push microwave WPT into new frontiers of scale, reliability, and regulatory sophistication.

References

Space-Based Solar Power: Unlocking Continuous, Global Clean Energy – World Journal of Advanced Research and Reviews – https://wjarr.com/sites/default/files/WJARR-2024-3323.pdf Wjarr

Solar Panels In Space Could Provide 80% Of Europe’s Renewable Energy By 2050 – The Guardian – https://www.theguardian.com/environment/2025/aug/21/solar-panels-in-space-could-provide-80-of-europes-renewable-energy-by-2050 The Guardian

Space Solar Power Project Ends First In-Space Mission With Successes And Lessons – Caltech – https://experts.caltech.edu/news/space-solar-power-project-ends-first-in-space-mission-with-successes-and-lessons Experts Guide

UK Startup Building Solar Power Beaming Tech For Space Applications – pv magazine – https://www.pv-magazine.com/2025/05/15/uk-startup-building-solar-power-beaming-tech-for-space-applications

Space-Based Solar Power: Final Report – NASA – https://www.nasa.gov/wp-content/uploads/2024/01/otps-sbsp-report-final-tagged-approved-1-8-24-tagged-v2.pdf NASA

Author and Co-Editor: Benoit Lafrance – Wireless Power Transfer Technologies, Montreal,  Peter Jonathan Wilcheck, Co-Editor, Miami, Florida.

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