Space Solar is a UK deep-tech company founded in 2022 and headquartered at the Harwell Campus in Oxfordshire, developing and commercialising Space-Based Solar Power (SBSP). Its flagship concept, CASSIOPeiA, envisions a 1.8 km-wide solar power satellite in geostationary orbit capable of beaming over 600 MW of continuous clean electricity to ground receiving stations anywhere on Earth, day and night, through all seasons and weather.

The company has achieved several world-first milestones, including the HARRIER prototype — the world's first 360° retrodirective phased array capable of wireless power transmission in any direction without mechanical rotation. In 2025, Space Solar completed the £1.7M CASSiDi programme (funded by the UK Space Agency and the Department for Energy Security and Net Zero), advancing the CASSIOPeiA design to Concept Maturity Level 4, and demonstrated the AlbaTRUSS robotic truss assembly in partnership with UKAEA's RACE division. The company is targeting a megawatt-scale commercial system by 2030 and a full 30 MW–GW product range within 12 years.

Space Solar's customers and partners include Reykjavik Energy (agreement to supply Iceland's first SBSP electricity by 2030), Lonestar (data storage hosted on orbital platforms), Thales Alenia Space, Frazer-Nash Consultancy, and BAE Systems subsidiary Prismatic. In April 2026 it was selected for the NATO DIANA 2026 accelerator cohort, validating the dual-use potential of its large in-space assembly and wireless power beaming technology. In September 2026 it won a £1.3M ARIA contract under Project HAWK to develop RF rectenna technology for high-altitude pseudo-satellites.

The company has raised approximately $7M in government grants and angel investment to date and, as of late 2025, was actively seeking to close its first formal seed round. Key government funders include the UK Space Agency, the Department for Energy Security and Net Zero, and ARIA.