For half a century, the economics of powering satellites have been dictated by exotic, expensive materials — a constraint so entrenched it was rarely questioned. Researchers at the University of Surrey have now done the questioning, modeling whether the humble silicon solar cell that covers rooftops worldwide might serve equally well in orbit, and finding that it could reduce power costs by up to 90%. The study does not merely propose a cheaper component; it suggests the industry has been solving the wrong problem, and that the path forward runs through a material space abandoned in 1977.
UK Study: Silicon Solar Cells Could Slash Satellite Power Costs by 90%
Once you put silicon behind space glass, the glass is what you're paying for.
Mark
So the study is saying silicon could cut costs by 90%. That's a staggering number. What's actually driving that?
Mimi
The price difference is enormous. Current space cells cost $250 to $450 per watt. Silicon costs tens of cents. But here's the thing—the study found that once you account for the protective glass you need in orbit, the savings are still 85 to 90%. The glass is the real expense now.
Luke
Wait. So the headline is "silicon cuts costs by 90%," but the actual finding is "silicon plus necessary shielding cuts costs by 85 to 90%." That's different. The glass is still a significant cost.
Mimi
Right. And that's actually the most important part of the study. Richards says the question isn't whether silicon is cheaper—it obviously is. The question is how to make silicon radiation-tolerant enough that you need less glass.
Mark
So the real work is still ahead. This isn't a solution; it's a direction.
Mimi
Exactly. The study proves the economics work if you can solve the radiation problem. But solving that is an engineering challenge, not a materials one.
Luke
How much of that 85-90% savings is from the silicon itself versus from the glass being thinner? The study doesn't seem to break that out clearly.
Mimi
The paper doesn't give a precise split, no. But Richards's point is that if you improve radiation tolerance, you get both benefits at once—lower cost and lower weight.
Mark
And lower weight means cheaper launches, which multiplies the savings.
Mimi
Exactly. A lighter satellite needs less fuel. That's a second-order benefit that makes the whole ecosystem cheaper.
Luke
The study modeled two specific spacecraft. How confident should we be that these savings would hold across different satellite designs?
Mimi
That's fair to question. They tested a CubeSat and a Micro Sat, which are relatively small. Larger satellites might have different economics. But the principle should hold.
O Pulso
- The price of powering a satellite has long been locked between $250 and $450 per watt — a cost so steep it shapes which missions get built and which never leave the drawing board.
- Silicon solar cells, refined by decades of terrestrial investment, now achieve efficiencies between 27.8% and 34.85%, quietly closing the gap that once made exotic triple-junction cells worth their price.
- The Surrey team's models across a CubeSat and a MicroSat showed 85–90% cost savings even after accounting for the protective glass silicon requires in orbit — a finding that reframes the entire economics of satellite power.
- The real obstacle is no longer the silicon cell itself but the heavy, expensive radiation-shielding glass wrapped around it, shifting the engineering challenge from materials competition to radiation hardening.
- If engineers can make silicon cells more radiation-tolerant — requiring less shielding — lighter satellites, cheaper launches, and expanded services from weather forecasting to disaster response could follow in rapid succession.
For half a century, the economics of powering satellites have been dictated by exotic, expensive materials — a constraint so entrenched it was rarely questioned. Researchers at the University of Surrey have now done the questioning, modeling whether the humble silicon solar cell that covers rooftops worldwide might serve equally well in orbit, and finding that it could reduce power costs by up to 90%. The study does not merely propose a cheaper component; it suggests the industry has been solving the wrong problem, and that the path forward runs through a material space abandoned in 1977.
A research team at the University of Surrey has spent months asking a question the aerospace industry largely stopped asking decades ago: could ordinary silicon solar cells — the kind found on residential rooftops — replace the exotic, costly materials that have powered satellites for fifty years? Their answer, published in Acta Astronautica, is a striking yes, with potential cost reductions of 85 to 90%.
For decades, spacecraft have depended on triple-junction cells made from gallium, indium, and germanium. These materials handle the radiation environment of orbit well, but they carry a punishing price — between $250 and $450 per watt. Silicon, by contrast, costs tens of cents per watt. And the efficiency gap that once justified the premium has narrowed considerably: modern silicon heterojunction cells reach 27.8% efficiency, while perovskite-silicon tandem designs have climbed to 34.85%.
The Surrey team modeled these economics against real hardware — one face of a 3U CubeSat and a MicroSat built by Surrey Satellite Technology Limited. Even with the protective space-qualified glass that silicon arrays need to survive radiation exposure, the projected savings held firm. That is not incremental progress; it is a structural shift in what it costs to put power in orbit.
Silicon is not a newcomer to space — it was the standard from 1958 to 1977, before gallium arsenide cells proved more efficient and radiation-resistant. What has changed is the sophistication of modern silicon manufacturing, shaped by billions of dollars of terrestrial solar investment that space technology never received.
The study's sharpest insight, however, is about where cost actually lives. Lead author Tommy Richards noted that once a silicon cell is wrapped in space-qualified protective glass, the glass becomes the dominant expense — the cell itself almost incidental. This reframes the challenge entirely: rather than asking whether silicon can compete with gallium, engineers should be asking how to make silicon more radiation-tolerant so that thinner, lighter shielding becomes sufficient.
The consequences extend well beyond aerospace budgets. Lighter satellites require less fuel, enabling cheaper launches. Lower hardware and launch costs together make previously unaffordable satellite networks viable — networks that underpin weather forecasting, global communications, agricultural monitoring, and disaster response. The material that space left behind half a century ago may be returning, not because it has changed, but because the world built around it has.
A team of researchers at the University of Surrey has spent months modeling a deceptively simple question: what if satellites used the same silicon solar cells that power rooftops on Earth instead of the exotic, expensive materials that have dominated space for the past fifty years? The answer, laid out in a new study published in Acta Astronautica, suggests the aerospace industry may have been looking in the wrong direction all along.
For decades, spacecraft have relied on triple-junction solar cells made from gallium, indium, and germanium—materials that deliver superior performance in the harsh radiation environment of orbit but come with a brutal price tag. A single watt of power from these cells costs between $250 and $450. Silicon, by contrast, costs tens of cents per watt. As of late 2025, the three leading silicon designs on the market—PERC, TOPCon, and heterojunction cells—averaged between $0.275 and $0.39 per watt. The efficiency gap that once justified the expense has also narrowed. Modern silicon heterojunction cells now reach 27.8% efficiency, while perovskite-silicon tandem designs have climbed to 34.85%.
The Surrey team tested these economics against real spacecraft. They modeled two scenarios: one side of a 3U CubeSat and a Micro Sat built by Surrey Satellite Technology Limited. Even accounting for the protective space-qualified glass that silicon arrays require to survive radiation exposure, the potential savings ran between 85% and 90%. That is not a marginal improvement. That is a fundamental reshaping of the cost structure for putting power in orbit.
Silicon is not new to space. From 1958 to 1977, it was the standard material for spacecraft solar arrays. The industry abandoned it when gallium arsenide cells proved more efficient and radiation-resistant, and the switch made sense at the time. What has changed is not silicon itself but the sophistication of how engineers now manufacture it. The cells available today are products of decades of refinement driven by the terrestrial solar industry, which has poured billions into optimization. Space technology, by contrast, has remained locked into a smaller, more specialized supply chain.
The real insight from the Surrey study, however, is not that silicon is cheap—it is where the remaining cost actually lives. Tommy Richards, a Ph.D. student and the study's lead author, put it plainly: once you wrap a silicon cell in space-qualified protective glass, the glass becomes the dominant expense. The cell itself is almost incidental. That reframes the entire problem. Instead of asking whether silicon can compete with gallium, engineers should be asking how to make silicon tougher against radiation so that thinner, lighter protective layers become sufficient. A cell that can tolerate more radiation damage means less shielding required, which means lower cost and lower weight simultaneously.
The implications ripple outward quickly. Lighter satellites need less fuel to reach orbit, which means cheaper launches. Cheaper hardware and cheaper launches together make it economically viable to deploy satellite networks that were previously too expensive to justify. Weather forecasting, global communications, navigation systems, Earth monitoring for agriculture and disaster response—all of these services depend on satellite infrastructure. Lower costs do not just benefit aerospace companies; they enable the expansion of services that cities use to prepare for extreme weather, that farmers use to optimize crops, that emergency responders use to coordinate rescue operations.
The next phase of work is not about materials science or fundamental physics. It is engineering: how to harden silicon cells against space radiation without adding cost and weight. For companies planning large satellite constellations or scientific missions, solving that problem could open the door to launch cadences and system affordability that seemed impossible just a few years ago. The material that space abandoned half a century ago may be about to return, not because it has changed, but because the world around it has.
Citações Notáveis
The interesting finding for us was not that silicon is cheaper but where the remaining cost sits. Once you put silicon cells behind space-qualified glass, the glass is what you are paying for.— Tommy Richards, Ph.D. student and lead author of the study
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