Tuesday, May 18, 2010

Japan Solar Sail


Today the Japan Aerospace Exploration Agency (JAXA) is set to launch the first spacecraft that will speed across the solar system using a hybrid solar sail—one propelled partly by solar pressure, partly by traditional solar power.

Dubbed Ikaros—for Interplanetary Kite-Craft Accelerated by Radiation of the Sun—the experimental craft will launch from the Tanegashima Space Center at 5:44 p.m. ET (6:44 a.m. Tuesday, local time).

Ikaros is hitching a ride into space aboard an H-IIA rocket, piggybacking with JAXA's Akatsuki Venus Climate Orbiter mission.

Once in space, the cylindrical, 677-pound (307-kilogram) craft will separate from the rocket and spin itself to unfurl its roughly 46-foot-wide (14-meter-wide) solar sail. (Related blog: "Tiny Solar Sail Pitched to Clean Up Space Junk.")

First proposed in the 1920s, solar sails are large reflective membranes that allow a spacecraft to be pushed by radiation pressure from sunlight, negating the need for heavy onboard fuel. (Explore a time line of space travel milestones.)

"It's the space equivalent of a yacht sailing on the sea," said Yuichi Tsuda, deputy project manager for Ikaros. Like wind filling a boat's sails, particles of light—or photons—streaming from the sun bounce onto a mirrorlike aluminized solar sail.

As each photon strikes, its momentum is transmitted to the spacecraft, which begins to gather speed in the almost frictionless environment of space. A solar sail can eventually reach speeds five to ten times greater than a rocket powered by conventional fuels.

Source: National Geographic

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Tuesday, November 11, 2008

Ota Solar City in Japan



By Mayumi Negishi

OTA, Japan (Reuters) - Solar panels glisten across Ota City's tiny Pal Town neighbourhood, nestled among strawberry fields in one of Japan's sunniest spots, a testament to the allure of renewable energy in this resource-poor country.

Three-quarters of Pal Town's homes are covered by solar panels, which are distributed for free and have become one of the main draw-cards for residents keen to minimise their power bills.


A great example for other countries to follow, even in a country were the sun doesn't most of the year. Mediterranean Europe and the south states of USA are the perfect locations for this model city to be built.

Full news article at Reuters

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