Space Solar (UK Based)

Technology

Space Solar's power beaming system is capable of operating in several orbits, adding flexibility, particularly in the early stages of implementation. Their final model will be in a geosynchronous orbit, allowing continuous power to each ground station. The core of the system consists of a sun-pointing satellite, called CASSIOPeiA, with a diameter of 1,400 m and mass of 800 tonnes, delivering 600+ MW to markets on Earth. This satellite beams radio frequency energy onto a 3.5 kilometer diameter rectenna on the ground that converts the energy back into electricity. The satellite has large primary mirrors at the top and bottom, always pointing at the sun, reflecting its light onto the PV receivers that collect the power. A helical structure in the middle, called the power core, consists of a spiral staircase with thin, step-like structures. Each small "step," or power module, is covered in PV cells on both sides and contains RF MMICs, amplifier circuitry, and antennas used for power transmission. The billions of antennas within the power core create a transmitting area which is a constant aperture size whatever orientation the satellite is with respect to Earth. This creates a solar aperture with the combined area of the two mirrors and an RF aperture formed from the array of antennas. 

Creating a collimated beam of radio waves at 5.8 GHz enables energy beaming through the atmosphere and weather with negligible loss, enabling 24/7 energy generation and transmission. The structure will be assembled in orbit through autonomous robotic systems.

Timeline

Space Solar has already demonstrated the ability to steer an energy beam through 360 degrees without moving parts and built the core of the CASSIOPeiA satellite. They have defined all necessary subsystems and built early prototype demonstrators of the beaming technology. In late June 2025, they completed CASSIDi, a project designed to “advance the design maturity” of the CASSIOPeiA satellite. Led by Space Solar in collaboration with 22 engineering organisations, it advanced the design of several key components, including power beaming technology, in-space assembly, and the ground receiver. It also confirmed that the “solar power satellite mass targets are achievable.”

Their five-year, hardware-intensive roadmap includes a plan to launch an in-space demonstration by 2028, followed by a complete end-to-end demonstration by 2030. Shortly after, they will have launched and commissioned the first commercial, revenue generating product, with an energy client already secured. The first model will be in a Low Earth Orbit, about 1,200 km, delivering a few megawatts of intermittent power. Using ultracapacitors and batteries, this can produce around 200 kilowatts of continuous power. By 2033, they will have commissioned a 100-megawatt geosynchronous system baseload and dispatchable power to global markets.

Building out manufacturing supply chains is one of the biggest challenges involved in the production process. They have begun sourcing the right materials and components and identifying reliable suppliers. Once this process is ironed out, they will be capable of building several gigawatt-scale systems every year.

Applications

Space-based solar power fills a critical niche in the energy ecosystem. It can serve as a baseload power source because, unlike ground-based solar, it is unaffected by weather or time of day. The power it produces can be easily modulated, allowing it to serve as a grid balancer and supply energy during peak price times. With international standards, the rectenna could be interoperable with other space-based solar power systems. Eventually, rectennas will likely be operated by power utilities, with the ability to receive power beamed from any number of in-space satellites. This will allow Space Solar to bid into the market much like any other energy provider.

In areas with limited energy infrastructure, Space Solar’s power supply model could give remote areas reliable power and with complete energy independence. The rectenna is a comparatively low impact structure and can provide up to 600 megawatts of power at a fraction of the land use required for an equivalent wind farm. This can revolutionize power access in less developed nations, as little complex, permanent, ground-based infrastructure is needed.

Space Solar’s system is also notable for its scalability. The system is highly modular, allowing new power collection systems to be built easily and quickly, enabling adaptation to growing energy demand.

Costs and Funding

Space Solar has received about $7 million in government grants and angel investment, and recently signed an agreement with Reykjavik Energy to deliver power to Iceland. Launch costs are also critical for financial viability. They estimate that at today’s $1,500 per kilogram, putting the structure in orbit accounts for around 70 percent of total CAPEX. Even at this cost, this would allow them to provide energy at about $30 per MWh, far below ground solar’s current price. When launch costs drop below $150 per kilogram, energy costs could fall to $10 per MWh. A study by Imperial College London found that integrating just 8 GW of SBSP into the UK energy grid would save £4.1 billion per year due to grid optimization, reducing the over-building of wind and solar capacity.

Policy

Since its founding, Space Solar, alongside the Space Energy Initiative, has been actively involved in developing a legal framework for SBSP in the UK. As securing global spectrum for radio-frequency power beaming is a pressing issue, Space Solar is working with international organisations and regulators to address the challenge. They are also promoting international regulations on in-orbit assembly and orbital debris prevention. Because energy is part of critical national infrastructure, they are addressing cyber and physical security aspects for SBSP. 

In addition to addressing spectrum management, Space Solar is conducting public outreach to explain and promote space-based solar power to the public. They are also coordinating with experts on space weather to ensure the RF beam will not be disrupted by the ionosphere and are performing environmental impact assessments.