China seems ready to build a space solar power plant

China seems ready to build a space solar power plant

Photo taken on June 5, 2022 shows the Zhuri ground verification facility at the South Campus of Xidian University in Xi'an, northwest China's Shaanxi Province.  (Xidian University/Handout via Xinhua)

Photo taken on June 5, 2022 shows the Zhuri ground verification facility at the South Campus of Xidian University in Xi’an, northwest China’s Shaanxi Province. (Xidian University/Handout via Xinhua)

China has made a breakthrough in its effort to build an in-space solar power plant to convert sunlight in space into electrical power to drive orbiting satellites or transmit power to Earth.

A research team from Xidian University this month completed the first full-system chain-scale ground-truthing for a space-based solar power plant, displaying several key know-hows for the futuristic project known as the name of Zhuri or chasing the sun.

The Space Solar Power Station (SSPS), a hotspot technology, is a space-based power generation system used to collect solar energy before converting it into electricity and then into microwaves. Sunlight is brightest outside the atmosphere and shines most of the day.

Then the microwave energy must be transmitted and collected by the receiving antenna either in space or on the surface of the Earth, which converts the microwaves back into electricity.

Key technologies verified include light concentration and high efficiency photoelectric conversion, microwave conversion, microwave emission at 55 meters and waveform optimization, measurement and control of microwave beam aiming, microwave reception and rectification, and the design of intelligent mechanical structures.


On the southern campus of the Xi’an-based university stands a 75-meter-tall steel structure. This is Zhuri’s ground check facility.

The team led by Duan Baoyan, the 67-year-old antenna expert from Xidian University, is tasked with simulating the generation and transmission of electricity on the ground. The main technological challenge is to minimize energy loss during energy changes of different forms.

First, the researchers worked to adjust the angles of the huge collector lens based on solar altitude. At the center of the lens are arrays of solar cells connected to transmitting antennas. They tested these antennas that transmit microwaves remotely to receivers.

The experiments were both investigative work and hard work. To carry a 200 kilogram antenna, Duan had to recruit students as temporary porters.

“You have to try again and again on the scene,” Duan said. “The computer simulation does not work.”

More than 100 researchers and students participated in the project. Thanks to their hard work, the audit successfully passed the exams on June 5, about three years ahead of schedule.


American aerospace scientist and engineer Peter Edward Glaser came up with the idea of ​​using satellites to transmit solar energy from space to Earth in 1968.

John C. Mankins, a former NASA physicist, proposed in 2012 an approach called SPS-ALPHA (Solar Power Satellite via Arbitrarily Large Phased Array). In 2015, Northrop Grumman Corporation in the United States sponsored a three-year US$17.5 million research for the development of the Space Solar Power Initiative (SSPI).

Duan proposed at the end of 2013 to launch China’s own initiative, then his team proposed the Chinese OMEGA technological approach.

“Compared to ALPHA, OMEGA’s power generation efficiency has increased by about 24%, and it is easily controlled and has better heat dissipation,” Duan said.

Japan has included space solar energy technology in its national space development plan. Its scientists tested microwave transmission at a distance of 55 meters in 2015, showing its technical advantage in wireless power transmission.

However, Japan’s experiment is not a complete chain because it lacks the light-to-electricity conversion test, Duan said.


In addition, engineers from the China Academy of Space Technology, the country’s state-owned spacecraft manufacturer, revealed earlier this month in a study published in the journal China Space Science and Technology a plan to promote this revolutionary technology.

A space high voltage transfer and wireless power transmission experiment is scheduled to be carried out in low Earth orbit in 2028, according to his plan.

The satellite will be capable of generating 10 kilowatts and carrying a quarter of a solar cell array, a microwave transmission antenna, a low power laser transmission payload and a transmission array of a few meters, in order to test power transmission over distances of 400 kilometers from orbit.

By 2030, they plan to expand the solar array to generate more than 100 kilowatts and test medium-power laser transmission over distances of 36,000 kilometers.

By 2035, the microwave transmission antenna is expected to be expanded to around 100 meters plus a power generation of 10 megawatts. The goal in 2050 is to build a commercially operated solar power plant that generates two gigawatts of electricity with an antenna about a kilometer long and a complex array of solar cells to be assembled in space.

“Space-earth transmission is our end goal, and it requires years of work,” Duan said. “But we can achieve some short-term goals.”

Duan said solar power in space can first be used to charge medium to small-sized satellites. “Now they have to be launched with huge payloads of solar panels and the panels are unable to harvest power from shadow regions as they orbit behind the Earth.”

In the near future, these satellites are expected to be equipped with foldable receiving antennas while launching these solar panels, according to Duan.

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