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.

Labels: Japan, Solar Energy, Solar News, Solar Technology

posted by Ertai at 9:31 AM