China plans to build huge space solar power station

China plans to build a huge solar power station 36,000 kilometres above the ground in an attempt to battle smog, cut greenhouse gases and solve energy crisis, much on the lines of an idea first floated in 1941 by fiction writer Isaac Asimov, state media reported today.
If realised, it will surpass the scale of the Apollo project and the International Space Station, and be the largest-ever space project.
The power station would be a super spacecraft on a geosynchronous orbit equipped with huge solar panels. The electricity generated would be converted to microwaves or lasers and transmitted to a collector on Earth, state-run Xinhua news agency reported.

In 1941, American science fiction writer Isaac Asimov had published a short story "Reason", in which a space station transmits energy collected from the sun using microwave beams.
Wang Xiji, an academician of the Chinese Academy of Sciences and an International Academy of Astronautics member, says Asimov's fiction has a scientific basis.
After devoting over 50 years to space technology research, Wang, 93, is an advocate for the station: "An economically viable space power station would be really huge, with the total area of the solar panels reaching 5 to 6 sq km."

That would be equivalent to 12 of Beijing's Tian'anmen Square, the largest public square in the world, or nearly two New York Central Parks. "Maybe people on Earth could see it in the sky at night, like a star," says Wang.

Wang says the electricity generated from the ground-based solar plants fluctuates with night and day and the weather, but a space generator collects energy 99 per cent of the time.
Space-based solar panels can generate ten times as much electricity as ground-based panels per unit area, says Duan Baoyan, a member of the Chinese Academy of Engineering.
"If we have space solar power technology, hopefully we could solve the energy crisis on Earth," Duan said.
Wang says whoever obtains the technology first "could occupy the future energy market. So it's of great strategic significance."
Countries such as the US and Japan have studied space solar power station. Japan leads the development of wireless power transmission technology.

However, many hurdles lie ahead: A commercially viable space power station would weigh 10,000 tons. But few rockets can carry a payload of over 100 tons to low Earth orbit.
"We need a cheap heavy-lift launchvehicle," says Wang, who designed China's first carrier rocket more than 40 years ago.
"We also need to make very thin and light solar panels. The weight of the panel must be less than 200 grams per square metre."
Li Ming, vice president of the China Academy of Space Technology, says, "China will build a space station in around 2020, which will open an opportunity to develop space solar power technology."

"When space solar energy becomes our main energy, people will no longer worry about smog or the greenhouse effect," concludes Wang.