Sun-rider: Japanese solar sail propelled by sun's photons
And these ones do more than just generate power – they’re able to help maneuver and accelerate the unmanned spacecraft to which they’re attached.
The so-called Ikaros solar sail is literally being pushed by sunlight, the space agency said on its website Friday. Particles of light from the sun known as photons exert pressure when they fall on the solar sail’s super-reflective panels, which are embedded into the sail.
The small but ongoing thrust exerts about 0.0002 pounds of force on the nearly 700-pound Ikaros. The kite-like drone, which can spin at up to 20 revolutions per minute, has thin-film solar cells built into its 46-feet-wide, 66-feet-diagonal frame.The craft was launched in May from the Tanegashima Space Center. Ikaros, which stands for Interplanetary Kite-craft Accelerated by Radiation of the Sun, was launched with the Akatsuki drone bound for orbit around Venus.
Soon, scientists expect to be able to control the Ikaros’ velocity, according to the nonprofit Planetary Society of Pasadena, which is tracking the drone's progress.
The society is planning its own solar sail launch for about a year from now. The LightSail 1 will be lighter – around 10 pounds - and cost under $2 million.
The Japanese space agency already has other grand plans to collect solar power in space by 2030 and beam the energy down to Earth using projects covering several square miles and costing billions of dollars.
"The main direction of all of this is that it’s a future propulsion method for planetary, interplanetary and maybe even interstellar missions,” said Louis Friedman, executive director of the Planetary Society. “Basically, it allows you to fly around the solar system without any fuel.”
Now that’s true space-age energy efficiency.
Photos: The Ikaros sail photographed by a tiny camera onboard. Credit: Japan Aerospace Exploration Agency.