Space Solar Station Tianhui-1 Successfully Transmits 10MW to Ground: Dawn of the Space Energy Era

Space Solar Station Tianhui-1 Successfully Transmits 10MW to Ground

On February 11, 2028, the China Aerospace Science and Technology Corporation (CASC) announced in Beijing that its experimental space solar satellite Tianhui-1 successfully completed a 10-megawatt microwave power transmission test on February 9. Power was beamed from geostationary orbit at 36,000km altitude to a ground receiving station in Chongqing's Bishan District.

"Tianhui-1 has validated the complete technology chain of space solar generation, transmission, and reception," said CASC space energy project chief designer Li Ming. "While 10MW only powers a small factory, it proves the concept works."

How It Works

Space solar power's core advantage: at geostationary orbit, solar panels receive approximately 99% annual sunlight at 5-10x ground intensity — no atmospheric attenuation or day-night cycle.

Tianhui-1 carries a 500-square-meter gallium arsenide solar array. Generated DC power is converted to 5.8GHz microwaves and directed to Earth via a 30-meter transmitting antenna. The Chongqing rectenna array spans approximately 10,000 square meters.

End-to-end transmission efficiency is approximately 12% — well below ground solar (22%) — but CASC targets 25% for next-generation systems.

Engineering Challenges

A commercial gigawatt-class station would require approximately 10 square kilometers of solar arrays weighing 100,000 tons, necessitating around 200 heavy-lift rocket launches.

SpaceX's reusable Starship provides a cost foundation. "Starship's per-kilogram launch cost has dropped to around $200," said SpaceX president Gwynne Shotwell. "A gigawatt-class space solar station remains a massive engineering challenge, but it's no longer unimaginable."

International Competition

Japan's JAXA targets a commercial station by 2035. ESA's SOLARIS initiative expects an investment decision in 2029. A UK government assessment concluded space solar is "feasible and worth investing in," recommending 16 billion pounds in international cooperation before 2030.

Environmental and Safety Considerations

Tianhui-1's microwave power density is approximately 230 watts per square meter — below direct solar radiation (1,000 W/m2) and deemed safe for birds and aircraft in the beam path. Environmental groups have called for comprehensive impact assessments before scaling up.

CASC plans to launch Tianhui-2 before 2030, targeting 100MW-class power transmission.