Japan Plans To Launch Solar Power Station In Space By 2040
Tokyo (AFP) Jan. 31, 2001
Undaunted by its less than glorious track record in space, Japan's ministry of economy, trade and industry (METI) has ambitious plans to launch a giant solar power station by 2040.
"We are starting research for a solar power generation satellite from fiscal year 2001 in April," Osamu Takenouchi, of METI's airplane, weapons and space industry division told AFP.
"We are planning to start operating the system in 2040," Takenouchi added.
"On Earth, clouds absorb sunlight, reducing (solar) power generation.
But in space, we will be able to generate electric power even at night," Takenouchi said.
METI plans to launch a satellite capable of generating one million kilowatts per second -- equivalent to the output of a nuclear plant -- into geostationary orbit, about 36,000 kilometers (22,320 miles) above the earth's surface.
The satellite will have two gigantic solar power-generating wing panels, each measuring three kilometers by a 1,000 meter diameter power transmission antenna between them, Takenouchi said.
The electricity produced will be sent back to earth in the form of microwaves with a lower intensity than those emitted by mobile phones.
"We intend to ensure the microwaves will not interrupt mobile phone and other telecommunications," Takenouchi said.
The receiving antenna on the ground, several kilometers in diameter, would probably be set up in a desert or at sea, and the electricity relayed from there along conventional cables he said.
The satellite is projected to weigh about 20,000 tonnes and the total construction cost is estimated at around two trillion yen (17 billion dollars), at current prices.
One economic hurdle so far is that it would cost about 23 yen per kilowatt hour to generate power in space compared to nine yen for thermal or nuclear power generation.
"But we will consider ways to lower the costs," Takenouchi said.
A similar plan was aired by the United States' National Aeronautics and Space Administration (NASA) but nothing has so far come of it.
One of the reasons for pursuing the dream of beaming power back to Earth is that scientists believe it could help reduce global warming.
"Solar power generation will not emit carbon dioxide, and so would benefit the environment compared to thermal power," Takenouchi said.
Besides, "the safety and other issues associated with nuclear power generation will disappear," Takenouchi said.
Honorary professor of space science at Tokyo University, Jun Nishimura said launching such a huge satellite was theoretically possible, adding the investment on research and development was money well spent.
Satellites being put into orbit nowadays weigh between 20 and 30 tonnes on average, Nishimura noted. "But 20 to 30 years earlier, satellites weighing only 100 kilograms could be launched."
"The International Space Station will also be huge."
While the lead time needed to develop the technology to build large-scale structures in space made 2040 a realistic target date, "the real question is cost performance," he said.
"Solar power generation in space can be realized only if the same amount of electricity can be generated at the same cost" as conventional means of power generation including construction costs, Nishimura said.
Japan started its space development programme in 1969 and has launched more than 30 rockets. But the programme has been blighted by a series of embarrassing failures.
Last November, the National Space Development Agency of Japan was forced to explode an H-2 rocket and satellite by remote control when it veered off course after lift-off.
In February 1998, a satellite was lost in space despite a successful separation from an H-2 rocket because it was released at the wrong altitude and sent into an elliptical orbit.
The H-2 is intended to be Japan's answer to Europe's Ariane commercial satellite launch vehicle.
Editor's Note: METI is the new name for what was formerly the Ministery of International Trade and Industry - the all powerful MITI.
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Conceptual Study of A Solar Power Satellite, SPS 2000
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