Space Solar Power Station SpaceSolar II: 500 kW Microwave Transmission Beams Power from Space to Earth

Space Solar Power Station SpaceSolar II: 500 kW Microwave Transmission Beams Power from Space to Earth

China Aerospace Science and Technology Corporation (CASC) today announced that the SpaceSolar II space solar power station has successfully completed a 500 kW microwave transmission test from geosynchronous orbit (36,000 kilometers). This is the first time humanity has continuously transmitted commercially significant electric power from space to the ground.

SpaceSolar II's core technology is microwave wireless power transmission. Solar panels in space convert sunlight into electricity, which is then converted into a 5.8 GHz microwave beam through a magnetron array and directionally transmitted to a rectenna array on the ground, where the microwaves are received and converted back into direct current.

The test lasted 72 hours, with the ground receiving station located near Jiuquan, Gansu Province. The receiving antenna array covered approximately 4,000 square meters, achieving a peak receiving power of 512 kW and an end-to-end conversion efficiency of 12.7%.

Liu Minghua, Chief Engineer of CASC's SpaceSolar project, said: "SpaceSolar II has validated the complete technology chain for space solar power generation. While 500 kW is only enough to supply about 500 households, the technical principles are now established. The next step is to scale up to the 10 MW level."

The advantage of space solar power is that it is unaffected by day-night cycles and weather. Solar panels in geosynchronous orbit can receive approximately 99% of solar radiation annually, compared to just 15-25% for ground-based solar plants. Additionally, solar radiation intensity in space is 5-10 times higher than on the ground (no atmospheric attenuation).

In terms of economics, current launch costs make space solar power approximately 20 times more expensive than ground-based solar. However, with the reusable development of SpaceX's Starship and China's Long March 9, launch costs are expected to decrease to one-tenth of current levels by 2035, at which point space solar power will become commercially competitive.

Professor John Mankins, Chairman of the International Academy of Astronautics' Energy Committee, commented: "SpaceSolar II is a critical step for space solar power from concept to reality. If launch costs continue to decline as expected, space solar could become an important source of global baseload power before 2040."

SpaceSolar III is planned for launch in 2033, targeting 10 MW of power to supply electricity to South China Sea islands and remote areas.