What if we could get our electricity from space? Our world desperately needs clean energy. It is now not just a preference but a necessity. With rising demands for electricity consumption, any way to produce cleaner energy is appreciated.
That’s where Solar-Based Solar Power (SBSP) comes into play. The core vision of SBSP is to capture solar energy in space where sunlight is uninterrupted, more intense, and unaffected by weather or night. Then, you take the harvested energy and transmit it wirelessly to Earth for use.
On Earth, solar power is limited by a number of factors that were mentioned above. For example, solar irradiation on the ground rarely reaches the theoretical maximum (~1,386 W/m² above the atmosphere), and after all the atmospheric losses are accounted for, typical solar panels get on the order of a few hundred W/m². This output can also be much lower depending on the panels’ location. Many panels, for example, in Ireland average around 20-50 W/m² over time under real conditions.
Therefore, the optimal place to locate our solar panels is the equator, but still, the atmosphere drastically decreases the power transmitted drastically and the day/night cycle still plays a crucial role.
In contrast, a satellite in high orbit (especially in geostationary orbit) could face the Sun nearly continuously, avoiding nights and weather, so panels located here could deliver far higher and far more stable energy outputs per square meter than ground-based arrays.
That continuous high-intensity energy is then converted via photovoltaics into electricity. Then it is converted into a microwave or a laser beam by a transmitter on the satellite, sent to Earth, and captured on a ground-based receiving station. This isn’t that easy, however, because the beam travels an immense distance to reach Earth, and by the time it does, the beam is kilometres wide. This means the receiving station would need to be massive to capture the beam.
However, the result would be a constant independent source of clean energy, immune to all the drawbacks Earth-based production faces.
The original idea for this system was introduced in the 1970s, and it was enormous. The size was 10 by 5 kilometres, and the mass was on the order of 50,000 tons. According to the information at the time, such a satellite would convert around 12% of incoming sunlight into electricity, delivering around 8,5 gigawatts of electrical power.
After power conversion and microwave-beaming losses, such a satellite might deliver around 5 GW of usable electricity to Earth. If we put that to scale, one of these could power five cities the size of Boston, continuously, day and night.
This idea was scrapped due to it being too challenging to get into operation and too expensive to make. However, modern scientists are starting to get back into this idea, making updated and modern designs.
For example, a newer design called CASSIOPeiA is much smaller - around 1,348 tons -, yet it produces around 1 GW of power. The big issue in the 1970s was the sheer amount of astronauts that would be needed to construct this satellite. It would take hundreds of people working in shifts for months on time to make this enormous project happen. The modern designs have abandoned this idea and are now looking at robots. If the individual parts of the solar array would be launched one by one, there would be small robots running on electric thrust engines waiting to connect them together.
Also, recent academic modelling suggests that SBSP could supply a large fraction of real-world energy demand. A 2025 paper from researchers at King's College London (KCL) found that integrating SBSP into a pan-Europe energy model could displace up to 80% of Europe’s intermittent wind and solar power needs.
Under that scenario, the overall cost of Europe’s power system could fall by 7-15%, and battery storage needs could drop by over 70%. SBSP has the potential to generate gigawatts of baseload electricity, enough to significantly offset or even replace large portions of terrestrial renewable and conventional energy infrastructure, at continental scales.
The concept of space-based solar power dates back to 1968, when American engineer Peter Glaser proposed using large geostationary solar collectors together with microwave transmitters.
In the 1970s and 80s, the system was considered severely impractical, mostly due to its enormous size and mass, which would also require an enormous amount of rocket launches, which at that time was around ~ US$10,000 per kilogram launched. Such a system would require hundreds of launches per year, and the Space Shuttle (which was meant to be able to perform hundreds of launches per year) was not able to keep up with such a cadence.
Today, our cost per kilogram launched into space has been reduced significantly from the 1970s; however, the cost is still too high for any company to be interested.
Technologies such as roll-out thin-film solar arrays dramatically reduce the mass and volume of solar panels, easing launch constraints. Today, some projections (mainly focused on the promises of SpaceX’s Starship) are saying that in the following years, the cost per kilogram is going to be as low as a few hundred dollars. This means that the cost to get CASSIOPeiA, for example, to be operational would be 4-5 billion USD.
This now compares to building a new nuclear power plant from scratch, which people would still rather do, because it is proven and working technology. No one will want to invest in such a system, because of its level of uncertainty and even if it has many pros and is, after becoming operational, fully emissionless, when they can build a power plant that produces a lot of emissions, but is proven and certain.
That’s why you probably haven’t heard a single thing about such technologies, but in the background, a lot of people are working to make such a satellite happen, and for as little money as possible. Who knows, maybe in the next few decades our electricity will come from space.
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